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Show HN: My $1k self-install, off-grid solar backup build for renters

236 points by nikodunk 2y ago

thot_experiment 2y ago
I have 1.2kW of used Sunpower panels I bought for $70/pop about 3 years ago. Buying decommissioned commercial install panels is insanely cost effective. It's crazy how cheap they go.
- dvdbloc 2y ago
  Any tips or guides on the best ways to get them? I’m interested
- greazy 2y ago
  Do they maintain efficiency?
  - nikodunk 2y ago
    Yeah! The Sunpower T5s mentioned above are still performing at near-max performance as far as I can tell. Things like shading or dust will influence modern panels way more than their age at this point IMO. Past 20 years I don't know - but for the next 10 years, it's seems to be a pretty good hack :)
    - arrowsmith 2y ago
      Why were they decommissioned if they're still at near-max performance?
      - thot_experiment 2y ago
        Because capitalism is a helluva drug.
      - nikodunk 2y ago
        Ya re-upping gov/state incentives is the theory I’ve heard in a few places. See e-bikes/EVs/general combustion leases where the same happens. Luckily, same as housing and transportation it dumps a bunch of lightly used but performant gear into the market for people like me.
      - sangnoir 2y ago
        I suppose the same reason companies get rid of perfectly serviceable laptops and servers: depreciation and chasing after fractionally larger efficiencies.
- ryjiao 2y ago
  Do you have any ideas for where I could get a similar deal?
- voisin 2y ago
  Where did you source them?
  - nikodunk 2y ago
    See links on https://sunboxlabs.com https://sunboxlabs.com
  - SkyPuncher 2y ago
    I was considering purchasing from this company: https://www.santansolar.com/product-category/solar-panels/ https://www.santansolar.com/product-category/solar-panels/
- hinkley 2y ago
  Do you buy “end of life” panels or panels removed during a remodel?
  - SkyPuncher 2y ago
    I've looked into it. My understanding is commercial installs are more sensitive to efficiency than consumers. I believe it's far more economical for them to squeeze everything they can out of an acreage than it is to simply build new. Between panels losing efficiency and newer, more efficient panels coming on the market, commercial installs tend to cycle out panels well before the end of their life. This leaves a second-hand market with some pretty crazy discounts.
    - 35mm 2y ago
      Also the cost of the structure supporting the panels is usually a lot more than the panels.
coyotespike 2y ago
I love how clear and to the point this page/guide is. Beautifully summarizes the downsides as well as the upsides. The system is even tempting to me as a homeowner not renter, but a similarly simple system that doesn't require running wires through the house might work better.
arrowsmith 2y ago
"We don't even notice power outages or public safety shut-offs anymore" I don't notice these where I live, because they literally never happen. Are there really places in the first world in 2024 where blackouts still happen frequently?
- loloquwowndueo 2y ago
  Yes. They are very common in parts of Canada during winter. They get fixed relatively quickly for sure but it’s a yearly occurrence.
  - moooo99 2y ago
    I’m curious as to what the reasons for such regular shutoffs are. I’m now 24 years old and I cannot recall ever experiencing a power outage, ever. So either I’m extraordinarily lucky or they aren’t as common here
    - bryanlarsen 2y ago
      Freezing rain and tornadoes. https://en.wikipedia.org/wiki/January_1998_North_American_ice_storm https://en.wikipedia.org/wiki/January_1998_North_American_ic...
    - loloquwowndueo 2y ago
      Recent examples: https://en.m.wikipedia.org/wiki/2023_Canada_ice_storm https://en.m.wikipedia.org/wiki/2023_Canada_ice_storm And https://www.msn.com/en-ca/weather/topstories/more-than-126000-still-without-power-as-spring-storm-rolls-through-quebec/ar-BB1l4aV9 https://www.msn.com/en-ca/weather/topstories/more-than-12600...
    - beeeeerp 2y ago
      I live in rural CO, and we get them pretty regularly. Extreme weather is pretty common out here, and the infrastructure isn’t as redundant for the mountain communities (I assume due to the cost/benefit ratio of building new lines). It’s not just power - we had a forest fire one year that burned a microwave tower & killed our cell phones _and_ internet for a week. The local businesses struggled for a day or two, because no one really carries cash anymore. I should add that kind of like the OP, I added an enphase LiFePO4 house battery and panels. They’ll keep critical loads running basically indefinitely, which has been a welcome change. We have gas heat, but I used to get nervous in the winter when the power went out (our boiler requires electricity to run).
bryanlarsen 2y ago
I've lost 2 freezers worth of food in the last 25 years due to power outages. I have since purchased a battery that can run a freezer in summer for a few hours or a furnace fan in winter for several days for the next outage. Adding a solar panel so I can use that battery continuously wouldn't pay for the battery, but it'd sure offset it considerably.
- neilv 2y ago
  Were they the lid on top freestanding freezers? How long were the outages, and what was the environment?
  - bryanlarsen 2y ago
    Yes, lid on top. 4 day outages in both cases.
    - lolinder 2y ago
      Would a few hours of runtime actually save your freezer food in the event of another 4 day outage?
      - Retric 2y ago
        It’s likely, freezers don’t operate continuously.
      - coffeebeqn 2y ago
        It’s not a few hours. It’s all sunlight hours plus a few hours from the battery per day
        lolinder 2y ago
        TFA's system, yes, but OP just bought a battery and is now considering adding a solar system.
      - briffle 2y ago
melenaboija 2y ago
I love this. I have been waiting for some sort of off grid solar kit that I can install "Ikea" install, i.e. with almost no idea about the matter take the instructions, plug and play.
- bryanlarsen 2y ago
  For more money and less effort you can purchase a "solar generator". It's a funny name for something that's basically a battery + inverter + mppt, but "solar generator" is the best thing to punch into Google.
- newsclues 2y ago
  These exist, multiple brands make and sell battery and solar ecosystems.
neilv 2y ago
The HTML title starts "The Landlord-Friendly...". It really depends on the landlord. I like the idea of solar, and of backups, and of figuring out how to live comfortably in rentals, and of being mobile, but... I'm pretty sure that my own real-life landlord would flip out, if he came to the door, and saw that charger box bolted to the wall, and the bare terminals of an Alibaba special "SCREMOWER" large lithium battery pack. Before he even saw that cabling. Which I think (with those lengths, and tacked up like that) would be an electrical code violation here. Would insurance even cover a fire? Also, if there's later an expensive roof leak, there'd be questions about whether it had been caused by installation of the panels (even though no holes were drilled). And is there a liability risk if the panel gets blown off. And would insurance cover any of that? Were I in landlord's position myself, I'd have much of the same concerns.
- cmclaughlin 2y ago
  I just left a similar comment. We were probably composing a the same time. Good point about the possibility of a roof leak and placing blame. I didn’t think of that.
  - hinkley 2y ago
    Years ago I fantasized about making a transformer designed to pass through a window. One coil on the outside, one on the inside. Unfortunately I don’t think you can split the core of a transformer and still get anywhere near the efficiency Also more recently I learned that these things can vibrate. Which would not be good for a window. You’d be better off passing a wire ribbon around the sash.
    - Animats 2y ago
      Split transformers for power transmission exist, but are rare. Here's a 3 KW system used for non-contact charging of electric forklifts, industrial mobile robots, and such.[1] 93% efficiency claimed. Probably not worth the trouble just to get power through a window. [1] https://www.wiferion.com/us/ https://www.wiferion.com/us/
brudgers 2y ago
Read your lease because most landlords are not going to be down with renters putting stuff on the roof...anyway… These days, $1k will buy a fair bit of a China made power brick. No need for solar access — for when the power goes out in a storm and/or at night. A big brick or several small ones is also less work; can live out of the way when not in use; and can be used when tailgating or car camping. For food cooling a small chest freezer has broad utility and unpowered will stay cool through a moderate outage.
complexworld 2y ago
When the battery is full where does the power produced by the panels go?
- repiret 2y ago
  Solar panels can sit in the sun without producing any power at all just fine. The sun will cause a voltage to develop on the solar panels output terminals, but if that voltage is not enough to cause current to flow, for example, because of battery charge controller is not drawing current, or because they’re not connected to anything, nothing bad happens.
- epistasis 2y ago
  Exactly the same place the power would go if the panels were in sun but the wires weren't connected to anything
- ThatPlayer 2y ago
  I don't know if OP's inverter supports it (looking at the manual real quick shows that it should), but the one I have will let you set any loads to use the battery when it's fully charged. Then set a point when it'll switch off battery, say 90%, and use the excess solar (after loads) to charge the battery again. So keeping the battery between 90%-100%, while still using most of the solar. I don't have any loads setup on mine because I don't want to run cables everywhere like that, so my battery just sits fully charged until I need it.
cmclaughlin 2y ago
I’m surprised the landlord is ok with this. I understand the panels might be rated to withstand some amount of wind, but there’s a huge liability if this project lead to injury. A good job was done considering the load on the indoor wiring, but the exposed wires on the outside of a building concern me. Typically wires have some level of insulation and/or conduit that reduces and contains the spread of fire. If wind did move the panels around, those wires could pull loose and start a fire. SF does not perform frequent building inspection, but if an inspector saw this they would almost certainly cite that this violates building code. In the event of injury, insurance might not pay out given how this is setup.
- avar 2y ago
  Around the 2 minute mark in the video you can see he's ratchet strapped the panels together, and in turn that strap is attached to the roof (looks to be looped around a pipe?). So he's not just relying on the wind rating of the panels. A better and perhaps code compliant way to do this (this is sometimes done this way here in NL, no idea about the US) is to bolt the panels to e.g. an aluminum frame, which you'd then hold to the roof with ballast, e.g. cinder blocks or heavy yard tiles. Depending on the panel area, frame and amount of ballast you can easily prove that there's no way the result would move due to weather, unless you were experiencing such apocalyptic winds that the house itself would be destroyed anyway.
_pdp_ 2y ago
If this is legal, it is excellent. When I remodelled our home some years ago, I had to rewire everything, including putting ethernet cables everywhere. It is not such a big deal if you are in the middle of it.
smallerfish 2y ago
Tangent: can anybody recommend a hybrid invertor that can prioritize solar over grid _without also_ prioritizing battery over grid when solar isn't available? Context: I have a solar + battery system for backup power purposes. We have long enough grid outages every so often that make it worthwhile, and I need to keep the batteries charged in preparation for those outages. However, 98% of the time the batteries are charged and the solar power is just being wasted (there is no grid tie back here); I'd like to actually use it. The invertor (which is cheap chinese) can prioritize "renewable over grid" and thus use the solar during the day, but in this mode it then uses the batteries at night, and recharges them from grid when it runs them down; this means lots of battery cycles and also potential for backup to be foiled if the grid goes down at the wrong time.
- jonnycoder 2y ago
  Check out the EG4 specs from signature solar. They have been reviewed a lot by Will Prowse on youtube and it’s what I would buy.
  - nikodunk 2y ago
    Seconded. The thing I’m using here is basically an EG4 knock off and I copied the wiring from the Will Prowse EG4 3000W mobile solar power guide (linked under how to) - which makes me think it’s the same board inside.
  - mcbishop 2y ago
    I like that their 3K inverter works with a 48-volt battery bank. They seem incredibly low cost for the value.
  - ThatPlayer 2y ago
    I have a similar Growatt from siganture solar. I'm pretty sure they're made by the same manufacturer as EG4. The cheaper one can do it, in a solar > utility > battery priority mode. But depending on your solar panel and consistent power draw, I'd maybe use the solar > battery > utility mode. It'll let you set a point to switch from battery to utility, the highest at 95%. That way when your usage is below your solar generation, you can still use the solar to charge the battery. A bit more wear and tear on the battery, but even less solar wasted. Assuming you can handle the batteries only being at 95% if you have an outage. If your usage is less than your solar generation, could even set it lower. I've been looking at something similar but different. My grid is fine, but I want to be able to use the batteries based on my time-of-use plan prices. I have less solar panels, but would want to charge my battery using grid power when prices are lower.
kshacker 2y ago
I do not want to fight with the utility or the insurance for such work, but this made me think: Can I set up something (I have a house) in my backyard + frontyard to just charge my EV? Catch the sun when it can, and then charge the car when connected. My PG&E bill says 56% of my usage is from midnight to 6 AM which is just EV + fridge. Although I pay a low rate on that, but imagine dropping half of your usage. I specifically pick out the EV as an example because by definition my system would never need to connect to the house or the grid, so I guess all I have is a disconnected battery (powerwall) to insure.
- jonnycoder 2y ago
  Yes very easy with a ground mount with 4 panels, a battery and inverter. I should write an article about it because I had planned to build something myself and keep all equipment outside and build a small wooden enclosure away from the house for it.
  - thechao 2y ago
    My EV lives outside & right beneath the only safely accessible part of my roof to put solar on... so an explanation would be grand! My only issue is that I need solar->battery->car, as the car is at work 3/7 days...
- yummypaint 2y ago
  You might consider something on the opposite end of the spectrum, specifically net metering. If your grid connection is reliable, it's even more economical to get a solar system without batteries that feeds the grid. Where I'm located people pay the difference between the two without regard for when the power was generated or consumed. It also means your system is more efficient because there are no battery losses.
  - mcbishop 2y ago
    Net metering is no longer available in PG&E territory.
winter_blue 2y ago
It sounds like the author of this piece lives in a jurisdiction without net metering. (The UK, perhaps?) If you have net metering, being able to push power back into the grid is a major plus.
- Toutouxc 2y ago
  It’s also a major pain in the ass in places where the grid isn’t exactly prepared for that. My parents are allowed to sell power from their EV installation. Their neighbor, who built a much smaller one a few months later, got denied.
- FireBeyond 2y ago
  I pity the poor linemen if you hook this contraption to feed back into the grid.
- epistasis 2y ago
  The bigger factor is that he's renting, and therefore whether the jurisdiction has net metering or not doesn't matter. But he's in San Francisco and California does not have net metering. I've been considering doing something like this as any grid-tied system is about $3/W for power, plus $500/kWh for storage. But an off-grid system done on your own is about $0.60/W plus $200/kWh for storage.
  - winter_blue 2y ago
    Wow, California’s NEM 3.0 seems absolutely horrible. I hope it gets repealed.
pbnjay 2y ago
As someone living in NC and paying only $0.09/kwh, that $0.55/kwh in SF is just nuts to me! This setup has a 12 year payoff here...
- worstspotgain 2y ago
  The rate schedules are complex. I'm paying ~$0.43/kWh, itemized as $0.13/kWh generation (Clean Power SF) and $0.30/kWh distribution (PG&E). If you use very little on the residential schedule I think it can drop pretty low, probably around $0.15/kWh.
  - pbnjay 2y ago
    My power is resold by the city so they don’t break it out, but a nearby county is 4.55c per kWh distribution charge and 5.96c per kWh generation charge.
  - danans 2y ago
    > If you use very little on the residential schedule I think it can drop pretty low, probably around $0.15/kWh. The lowest price on the PG&E tiered rate plan E1 (implied by the words "If you use very little ...") is $0.42/kWh. Even the most variable rate EV2A plan has an off-peak price of $0.35/kWh. I don't see any way to get a price of $0.15 kWh.
    - worstspotgain 2y ago
      I stand corrected, it's been a while since I last looked at rates. I think the ~$0.15/kWh I remembered was from SVP in Santa Clara, not PG&E. https://www.siliconvalleypower.com/residents/rates-and-fees https://www.siliconvalleypower.com/residents/rates-and-fees
      - worstspotgain 2y ago
        BTW, the actual lowest rates for SF are closer to ~$0.26/kWh, and may be lower during the winter months at the lowest usage tier ("below baseline.") https://www.pge.com/assets/pge/docs/account/alternate-energy-providers/cleanpowersf_rateclasscomparison.pdf https://www.pge.com/assets/pge/docs/account/alternate-energy... I can't work it out exactly without doing more research than is worth. As I said, the schedules are complex, maybe someone more versed in this can chime in. Hopefully SF will finally manage to force PG&E to sell it the city's grid. I doubt it will lead to rates as low as Santa Clara's, though. https://sfpuc.org/about-us/news/its-high-time-san-francisco-buy-pges-grid-city https://sfpuc.org/about-us/news/its-high-time-san-francisco-...
millebe 2y ago
This is dangerous and illegal everywhere in the United States. DO NOT DO THIS! All 50 states have adopted NFPA 70, the National Electric Code, and the linked article shows a bunch of things that absolutely DO require a permit and would absolutely FAIL to be approved: First and foremost, running bare high voltage DC wires through an open window is in violation of a pile of building codes and very dangerous. The linked solar panels have an open circuit voltage of 64.8V, so with four of them in parallel there can be 260V of direct current. This can and will kill you, especially if you touch it in such a way where muscular tetanus prevents you from releasing the cable. Electrical extension cords are intended to be temporary, and the article's use of them violates a bunch of codes. Here are some of the relevant ones: 400.10 Uses Permitted (A) Uses Flexible cords and flexible cables shall be used only for the following: (1) Pendants. (2) Wiring of luminaires. (3) Connection of portable luminaires, portable and mobile signs, or appliances. (4) Elevator cables. (5) Wiring of cranes and hoists. (6) Connection of utilization equipment to facilitate frequent interchange. (7) Prevention of the transmission of noise or vibration. (8) Appliances where the fastening means and mechanical connections are specifically designed to permit ready removal for maintenance and repair, and the appliance is intended or identified for flexible cord connection. (9) Connection of moving parts. (10) Where specifically permitted elsewhere in this Code. (11) Between an existing receptacle outlet and an inlet, where the inlet provides power to an additional single receptacle outlet. The wiring interconnecting the inlet to the single receptacle outlet shall be a Chapter 3 wiring method. The inlet, receptacle outlet, and Chapter 3 wiring method, including the flexible cord and fittings, shall be a listed assembly specific for this application. 400.12 Uses Not Permitted Unless specifically permitted in 400.10, flexible cables, flexible cord sets, and power supply cords shall not be used for the following: (1) As a substitute for the fixed wiring of a structure (2) Where run through holes in walls, structural ceilings, suspended ceilings, dropped ceilings, or floors (3) Where run through doorways, windows, or similar openings (4) Where attached to building surfaces Exception to (4): Flexible cord and flexible cable shall be permitted to be attached to building surfaces in accordance with 368.56(B). (5) Where concealed by walls, floors, or ceilings or located above suspended or dropped ceilings Exception to (5): Flexible cord and flexible cable shall be permitted if contained within an enclosure for use in Other Spaces Used for Environmental Air as permitted by 300.22(C)(3). (7) Where subject to physical damage 400.17 Protection From Damage Flexible cords and flexible cables shall be protected by bushings or fittings where passing through holes in covers, outlet boxes, or similar enclosures. You absolutely cannot and should not run bare wires through a window. This manages to violate basically all of Chapter 3 of the NEC: 300.3 Conductors (A) Single Conductors Single conductors specified in Table 310.104(A) shall only be installed where part of a recognized wiring method of Chapter 3. 300.4 Protection Against Physical Damage Where subject to physical damage, conductors, raceways, and cables shall be protected. 300.6 Protection Against Corrosion and Deterioration Raceways, cable trays, cablebus, auxiliary gutters, cable armor, boxes, cable sheathing, cabinets, elbows, couplings, fittings, supports, and support hardware shall be of materials suitable for the environment in which they are to be installed. 300.11 Securing and Supporting (A) Secured in Place Raceways, cable assemblies, boxes, cabinets, and fittings shall be securely fastened in place. 300.12 Mechanical Continuity — Raceways and Cables Raceways, cable armors, and cable sheaths shall be continuous between cabinets, boxes, fittings, or other enclosures or outlets. 310.10 Uses Permitted (C) Wet Locations Insulated conductors and cables used in wet locations shall comply with one of the following: Be moisture-impervious metal-sheathed Be types MTW, RHW, RHW-2, TW, THW, THW-2, THHW, THWN, THWN-2, XHHW, XHHW-2, or ZW Be of a type listed for use in wet locations (D) Locations Exposed to Direct Sunlight Insulated conductors or cables used where exposed to direct rays of the sun shall comply with (D)(1) or (D)(2): Conductors and cables shall be listed, or listed and marked, as being sunlight resistant Conductors and cables shall be covered with insulating material, such as tape or sleeving, that is listed, or listed and marked, as being sunlight resistant Both the solar panels and the inverter are listed products and are required to be installed in accordance with their listings. In particular, this means they must be permanently fastened to the structure in the manner of the manufacturer's instructions. 110.3 Examination, Identification, Installation, Use, and Listing (Product Certification) of Equipment (B) Installation and Use Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling. The solar panels must be fastened to the structure in a way that resists wind and weather loads. There are entire sections of the NEC and various IBC codes devoted to this. Other various code sections that this would fail: 110.8 Wiring Methods Only wiring methods recognized as suitable are included in this Code. The recognized methods of wiring shall be permitted to be installed in any type of building or occupancy, except as otherwise provided in this Code. 110.12 Mechanical Execution of Work Electrical equipment shall be installed in a neat and workmanlike manner. 110.13 Mounting and Cooling of Equipment (A) Mounting Electrical equipment shall be firmly secured to the surface on which it is mounted. Wooden plugs driven into holes in masonry, concrete, plaster, or similar materials shall not be used. 110.26 Spaces About Electrical Equipment Access and working space shall be provided and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment. (A) Working Space Working space for equipment operating at 1000 volts, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized shall comply with the dimensions of 110.26(A)(1), (A)(2), (A)(3), and (A)(4) or as required or permitted elsewhere in this Code. (B) Clear Spaces Working space required by this section shall not be used for storage. When normally enclosed live parts are exposed for inspection or servicing, the working space, if in a passageway or general open space, shall be suitably guarded. (E) Dedicated Equipment Space All switchboards, switchgear, panelboards, and motor control centers shall be located in dedicated spaces and protected from damage. (1) Indoor Indoor installations shall comply with 110.26(E)(1)(a) through (E)(1)(d). (a) Dedicated Electrical Space. The space equal to the width and depth of the equipment and extending from the floor to a height of 1.8 m (6 ft) above the equipment or to the structural ceiling, whichever is lower, shall be dedicated to the electrical installation. No piping, ducts, leak protection apparatus, or other equipment foreign to the electrical installation shall be located in this zone. (2) Outdoor Outdoor installations shall comply with 110.26(E)(2)(a) through (c). (a) Installation Requirements. Outdoor electrical equipment shall be the following: (1) Installed in identified enclosures 110.27 Guarding of Live Parts (A) Live Parts Guarded Against Accidental Contact Except as elsewhere required or permitted by this Code, live parts of electrical equipment operating at 50 to 1000 volts, nominal shall be guarded against accidental contact by approved enclosures or by any of the following means: (1) By location in a room, vault, or similar enclosure that is accessible only to qualified persons. (3) By location on a balcony, gallery, or platform elevated and arranged so as to exclude unqualified persons. (4) By elevation above the floor or other working surface as follows: A minimum of 2.5 m (8 ft) for 50 volts to 300 volts between ungrounded conductors (B) Prevent Physical Damage In locations where electrical equipment is likely to be exposed to physical damage, enclosures or guards shall be so arranged and of such strength as to prevent such damage.
Cheer2171 2y ago
> It's not wired into the meter, doesn't require a permit, etc. This is 100% a fire hazard and would get your home insurance voided.
valianteffort 2y ago
You can buy 256Wh battery banks for around $150 now. You can pair them with a timer for charging/topping off at night when electricity is cheap. They even accept solar input. Throw one in every room and between appliances like the fridge or oven. Now you have a UPS for your whole house and the cheapest energy rates throughout the day.
- epistasis 2y ago
  Do those have an inverter built in? If not, at $600/kWh very pricy compared to what this guy used at $190/kWh for batteries, or $360/kWh including the inverter: https://www.amazon.com/dp/B08G81TKC6?ie=UTF8&th=1&linkCode=sl1&tag=gridlesskits-20&linkId=33ade7afc845a76a2271b39f1e6ed35a&language=en_US&ref_=as_li_ss_tl https://www.amazon.com/dp/B08G81TKC6?ie=UTF8&th=1&linkCode=s... Also, $190/kWh is so cheap. Its hard to believe how fast costs are falling for energy storage.
  - ianburrell 2y ago
    If is he talking power bank, then big ones, usually called power stations, have inverters. But they can’t be used as UPS since they cut power when switching sources.
- grobbyy 2y ago
  My experience is that power banks and UPSes fail more often than my power. I keep a couple charged, but with nothing plugged in. I sometimes plug things in before a major storm, planned outage, or after an unplanned one.
  - smeej 2y ago
    This is funny to me because mine just died unceremoniously during a snowstorm and it made me realize there should really be a testing cycle built in.
- xyzzy123 2y ago
  Hm fridge sure, but oven? 256Wh is going to power an electric oven for like, 5 minutes. Doesn't seem useful.
happytiger 2y ago
What’s the status in insurance for this thing? Generally this doesn’t seem like it would be covered under renters insurance. I can’t imagine a landlord in existence that wouldn’t throw a fit about something like this.
cameldrv 2y ago
All of the code/safety/landlord issues notwithstanding, the price is pretty incredible. If I plug my address into the PVWatts calculator, given the insane price increases from PG&E over the past few years, the payback period is one year. Beyond the fantastic economics, you're getting a decent emergency backup system that should cover at least your fridge, lights, and various electronics.
deeth_starr_v 2y ago
This reminds me of the time when I built a battery stereo power amplifier and then only used it a few times because I didn’t want to risk burning the apartment complex down. It was fun building it though.
magicbuzz 2y ago
The all-in-one 3kW inverter/controller that he uses is for 110V AC output (using the 48V battery). In the article he linked to, the system uses an EG4 3000EHV-48 that also outputs 110V AC. Are there equivalent all-in-ones that would provide 230/240V AC for use in Australia/New Zealand?
- avar 2y ago
  If you search for the manufacturer shown (PowMr) it looks like they make both 110v and 220v variants. This looks to be the same or similar product for 220v: https://a.aliexpress.com/_EwlP4Cf https://a.aliexpress.com/_EwlP4Cf
  - mcbishop 2y ago
    I think this is single phase. 230V is a common single-phase voltage outside North America.
- mcbishop 2y ago
  I don't know of a 3kW inverter that outputs split phase. But you could get the higher-rated EG4 6000XP.
  - Scoundreller 2y ago
    AU/NZ 240V wouldn't be split phase
threemux 2y ago
The quality of the components in this system is suspect. Check out Mobile Solar Power/ Will Prowse for unbiased, in depth reviews for this stuff
selfie 2y ago
How is self install possible if you are not a licensed electrician. Something like this could shock someone if not earthed properly, for example.
ricardobeat 2y ago
Hmm.. I wouldn't trust that "2,500W power distribution strip", or the extension cord itself, to actually be safe when you have a fridge, living room appliances and the induction cooktop pulling 1.2KW all at once. Fire waiting to happen.
- chgs 2y ago
  Do US cables not have appropriate fuses? If it’s a 10A cable then have a 10A fuse. Pull more than that and the fuse goes.
  - ricardobeat 2y ago
    Guess you're from the UK? I think it's one of the only places in the world that does that. No, usually not, though better power strips will have one. But you don't need to go over the specified amps to cause a fire, there are multiple places that could overheat - extension cable, connections, solder points - while still being under the fuse rating if this thing is running at max power for a long time. The main job of a fuse is to protect against power surges / short circuits.
  - Havoc 2y ago
    That's only necessarily in the UK because of the ring circuits https://en.wikipedia.org/wiki/Ring_circuit https://en.wikipedia.org/wiki/Ring_circuit
    - chgs 2y ago
      Sounds like it’s neccersary in the us too if you have cables rates at lower power than the circuit. I have lights with cables rated at well under 3A, they plug into the same outlet that a 10A cable can plug into. How do you stop a fault which draws 7A?
asdefghyk 2y ago
About under rated extension cords. My question is if in a house a person plugs in a under rated extension cord into a normal powerpoint and connects equipment to the other end, such that the current exceeds the extension cords current rating , and a FIRE results, would the insurance company pay??? ( ie this is in a house without any of the this DIY solar. cables or battery etc) . would be interesting question.
- zo1 2y ago
  No idea of the specifics. But a good heuristic to go off of is to assume that no they won't pay out if they can find anything that is remotely plausible to have been the cause or contributing factor.
choilive 2y ago
Wow... This should be added to the FAQ's under "Whats the catch?": At least a dozen code violations that risks burning down your/your landlord's property, serious injury or worse - loss of life - and opens yourself to VERY large liabilities. A more proper way to do this would be to have one self contained outdoor box rated to contain high energy batteries, have your inverter and PDU as part of that package and then plug your the panels to that. When you have a power outage go out and grab your backup battery box. This eliminates the bulk of the issues. Although, that raises the obvious solution that you could just spend a bit more money and get one of those self contained "battery generators", which have been properly engineered and designed, and are also pretty portable. Another thing I would add is adding some sandbags to the solar panels so that they don't fly off the roof in a high wind scenario. Theres a reason why when doing a rooftop installation code will specify this if not being directly bolted. (Technically a structural engineer will need to do a load calculation, but for this size of install the risks are minimal compared to the risks inherent in the rest of the system)
turtlebits 2y ago
Forget the landlord (who is already unlikely to give roof access, let alone run electrical wires outside), this immediately fails the WAF (wife acceptance factor) due to the hideous cable install.
- stbenjam 2y ago
  I know right? I love the caption on one of those photos about “relatively neat” cable runs.
ProllyInfamous 2y ago
You should absolutely NEVER place solar panels directly upon a roof as many of the linked website photographs demonstrate. Solar cells need ventilation on their undersides, and without it will rapidly be damaged (i.e. become more inefficient). Long-term, water trapped underneath may encourage shinglerot.
anonymousiam 2y ago
Nice Project! I did a similar project in 2003, but obviously the technology has improved a lot since then. I've previously posted some details here: https://news.ycombinator.com/item?id=36000824 https://news.ycombinator.com/item?id=36000824 The thing that stood out to me about this project was the lack of any hardware to secure the panels to the roof, which is absolutely necessary to prevent wind damage.
35mm 2y ago
Any tips for going through doors with the cabling?

236 points by nikodunk 2y ago

I have 1.2kW of used Sunpower panels I bought for $70/pop about 3 years ago. Buying decommissioned commercial install panels is insanely cost effective. It's crazy how cheap they go.

dvdbloc 2y ago
Any tips or guides on the best ways to get them? I’m interested
greazy 2y ago
Do they maintain efficiency?
- nikodunk 2y ago
  Yeah! The Sunpower T5s mentioned above are still performing at near-max performance as far as I can tell. Things like shading or dust will influence modern panels way more than their age at this point IMO. Past 20 years I don't know - but for the next 10 years, it's seems to be a pretty good hack :)
  - arrowsmith 2y ago
    Why were they decommissioned if they're still at near-max performance?
    - thot_experiment 2y ago
      Because capitalism is a helluva drug.
    - nikodunk 2y ago
      Ya re-upping gov/state incentives is the theory I’ve heard in a few places. See e-bikes/EVs/general combustion leases where the same happens. Luckily, same as housing and transportation it dumps a bunch of lightly used but performant gear into the market for people like me.
    - sangnoir 2y ago
      I suppose the same reason companies get rid of perfectly serviceable laptops and servers: depreciation and chasing after fractionally larger efficiencies.
ryjiao 2y ago
Do you have any ideas for where I could get a similar deal?
voisin 2y ago
Where did you source them?
- nikodunk 2y ago
  See links on https://sunboxlabs.com https://sunboxlabs.com
- SkyPuncher 2y ago
  I was considering purchasing from this company: https://www.santansolar.com/product-category/solar-panels/ https://www.santansolar.com/product-category/solar-panels/
hinkley 2y ago
Do you buy “end of life” panels or panels removed during a remodel?
- SkyPuncher 2y ago
  I've looked into it. My understanding is commercial installs are more sensitive to efficiency than consumers. I believe it's far more economical for them to squeeze everything they can out of an acreage than it is to simply build new. Between panels losing efficiency and newer, more efficient panels coming on the market, commercial installs tend to cycle out panels well before the end of their life. This leaves a second-hand market with some pretty crazy discounts.
  - 35mm 2y ago
    Also the cost of the structure supporting the panels is usually a lot more than the panels.

coyotespike 2y ago

I love how clear and to the point this page/guide is. Beautifully summarizes the downsides as well as the upsides. The system is even tempting to me as a homeowner not renter, but a similarly simple system that doesn't require running wires through the house might work better.

arrowsmith 2y ago

"We don't even notice power outages or public safety shut-offs anymore" I don't notice these where I live, because they literally never happen. Are there really places in the first world in 2024 where blackouts still happen frequently?

loloquwowndueo 2y ago
Yes. They are very common in parts of Canada during winter. They get fixed relatively quickly for sure but it’s a yearly occurrence.
- moooo99 2y ago
  I’m curious as to what the reasons for such regular shutoffs are. I’m now 24 years old and I cannot recall ever experiencing a power outage, ever. So either I’m extraordinarily lucky or they aren’t as common here
  - bryanlarsen 2y ago
    Freezing rain and tornadoes. https://en.wikipedia.org/wiki/January_1998_North_American_ice_storm https://en.wikipedia.org/wiki/January_1998_North_American_ic...
  - loloquwowndueo 2y ago
    Recent examples: https://en.m.wikipedia.org/wiki/2023_Canada_ice_storm https://en.m.wikipedia.org/wiki/2023_Canada_ice_storm And https://www.msn.com/en-ca/weather/topstories/more-than-126000-still-without-power-as-spring-storm-rolls-through-quebec/ar-BB1l4aV9 https://www.msn.com/en-ca/weather/topstories/more-than-12600...
  - beeeeerp 2y ago
    I live in rural CO, and we get them pretty regularly. Extreme weather is pretty common out here, and the infrastructure isn’t as redundant for the mountain communities (I assume due to the cost/benefit ratio of building new lines). It’s not just power - we had a forest fire one year that burned a microwave tower & killed our cell phones _and_ internet for a week. The local businesses struggled for a day or two, because no one really carries cash anymore. I should add that kind of like the OP, I added an enphase LiFePO4 house battery and panels. They’ll keep critical loads running basically indefinitely, which has been a welcome change. We have gas heat, but I used to get nervous in the winter when the power went out (our boiler requires electricity to run).

bryanlarsen 2y ago

I've lost 2 freezers worth of food in the last 25 years due to power outages. I have since purchased a battery that can run a freezer in summer for a few hours or a furnace fan in winter for several days for the next outage. Adding a solar panel so I can use that battery continuously wouldn't pay for the battery, but it'd sure offset it considerably.

neilv 2y ago
Were they the lid on top freestanding freezers? How long were the outages, and what was the environment?
- bryanlarsen 2y ago
  Yes, lid on top. 4 day outages in both cases.
  - lolinder 2y ago
    Would a few hours of runtime actually save your freezer food in the event of another 4 day outage?
    - Retric 2y ago
      It’s likely, freezers don’t operate continuously.
    - coffeebeqn 2y ago
      It’s not a few hours. It’s all sunlight hours plus a few hours from the battery per day
      - lolinder 2y ago
        TFA's system, yes, but OP just bought a battery and is now considering adding a solar system.
    - briffle 2y ago

melenaboija 2y ago

I love this. I have been waiting for some sort of off grid solar kit that I can install "Ikea" install, i.e. with almost no idea about the matter take the instructions, plug and play.

bryanlarsen 2y ago
For more money and less effort you can purchase a "solar generator". It's a funny name for something that's basically a battery + inverter + mppt, but "solar generator" is the best thing to punch into Google.
newsclues 2y ago
These exist, multiple brands make and sell battery and solar ecosystems.

neilv 2y ago

The HTML title starts "The Landlord-Friendly...". It really depends on the landlord. I like the idea of solar, and of backups, and of figuring out how to live comfortably in rentals, and of being mobile, but... I'm pretty sure that my own real-life landlord would flip out, if he came to the door, and saw that charger box bolted to the wall, and the bare terminals of an Alibaba special "SCREMOWER" large lithium battery pack. Before he even saw that cabling. Which I think (with those lengths, and tacked up like that) would be an electrical code violation here. Would insurance even cover a fire? Also, if there's later an expensive roof leak, there'd be questions about whether it had been caused by installation of the panels (even though no holes were drilled). And is there a liability risk if the panel gets blown off. And would insurance cover any of that? Were I in landlord's position myself, I'd have much of the same concerns.

cmclaughlin 2y ago
I just left a similar comment. We were probably composing a the same time. Good point about the possibility of a roof leak and placing blame. I didn’t think of that.
- hinkley 2y ago
  Years ago I fantasized about making a transformer designed to pass through a window. One coil on the outside, one on the inside. Unfortunately I don’t think you can split the core of a transformer and still get anywhere near the efficiency Also more recently I learned that these things can vibrate. Which would not be good for a window. You’d be better off passing a wire ribbon around the sash.
  - Animats 2y ago
    Split transformers for power transmission exist, but are rare. Here's a 3 KW system used for non-contact charging of electric forklifts, industrial mobile robots, and such.[1] 93% efficiency claimed. Probably not worth the trouble just to get power through a window. [1] https://www.wiferion.com/us/ https://www.wiferion.com/us/

brudgers 2y ago

Read your lease because most landlords are not going to be down with renters putting stuff on the roof...anyway… These days, $1k will buy a fair bit of a China made power brick. No need for solar access — for when the power goes out in a storm and/or at night. A big brick or several small ones is also less work; can live out of the way when not in use; and can be used when tailgating or car camping. For food cooling a small chest freezer has broad utility and unpowered will stay cool through a moderate outage.

complexworld 2y ago

When the battery is full where does the power produced by the panels go?

repiret 2y ago
Solar panels can sit in the sun without producing any power at all just fine. The sun will cause a voltage to develop on the solar panels output terminals, but if that voltage is not enough to cause current to flow, for example, because of battery charge controller is not drawing current, or because they’re not connected to anything, nothing bad happens.
epistasis 2y ago
Exactly the same place the power would go if the panels were in sun but the wires weren't connected to anything
ThatPlayer 2y ago
I don't know if OP's inverter supports it (looking at the manual real quick shows that it should), but the one I have will let you set any loads to use the battery when it's fully charged. Then set a point when it'll switch off battery, say 90%, and use the excess solar (after loads) to charge the battery again. So keeping the battery between 90%-100%, while still using most of the solar. I don't have any loads setup on mine because I don't want to run cables everywhere like that, so my battery just sits fully charged until I need it.

cmclaughlin 2y ago

I’m surprised the landlord is ok with this. I understand the panels might be rated to withstand some amount of wind, but there’s a huge liability if this project lead to injury. A good job was done considering the load on the indoor wiring, but the exposed wires on the outside of a building concern me. Typically wires have some level of insulation and/or conduit that reduces and contains the spread of fire. If wind did move the panels around, those wires could pull loose and start a fire. SF does not perform frequent building inspection, but if an inspector saw this they would almost certainly cite that this violates building code. In the event of injury, insurance might not pay out given how this is setup.

avar 2y ago
Around the 2 minute mark in the video you can see he's ratchet strapped the panels together, and in turn that strap is attached to the roof (looks to be looped around a pipe?). So he's not just relying on the wind rating of the panels. A better and perhaps code compliant way to do this (this is sometimes done this way here in NL, no idea about the US) is to bolt the panels to e.g. an aluminum frame, which you'd then hold to the roof with ballast, e.g. cinder blocks or heavy yard tiles. Depending on the panel area, frame and amount of ballast you can easily prove that there's no way the result would move due to weather, unless you were experiencing such apocalyptic winds that the house itself would be destroyed anyway.

_pdp_ 2y ago

If this is legal, it is excellent. When I remodelled our home some years ago, I had to rewire everything, including putting ethernet cables everywhere. It is not such a big deal if you are in the middle of it.

smallerfish 2y ago

Tangent: can anybody recommend a hybrid invertor that can prioritize solar over grid _without also_ prioritizing battery over grid when solar isn't available? Context: I have a solar + battery system for backup power purposes. We have long enough grid outages every so often that make it worthwhile, and I need to keep the batteries charged in preparation for those outages. However, 98% of the time the batteries are charged and the solar power is just being wasted (there is no grid tie back here); I'd like to actually use it. The invertor (which is cheap chinese) can prioritize "renewable over grid" and thus use the solar during the day, but in this mode it then uses the batteries at night, and recharges them from grid when it runs them down; this means lots of battery cycles and also potential for backup to be foiled if the grid goes down at the wrong time.

jonnycoder 2y ago
Check out the EG4 specs from signature solar. They have been reviewed a lot by Will Prowse on youtube and it’s what I would buy.
- nikodunk 2y ago
  Seconded. The thing I’m using here is basically an EG4 knock off and I copied the wiring from the Will Prowse EG4 3000W mobile solar power guide (linked under how to) - which makes me think it’s the same board inside.
- mcbishop 2y ago
  I like that their 3K inverter works with a 48-volt battery bank. They seem incredibly low cost for the value.
- ThatPlayer 2y ago
  I have a similar Growatt from siganture solar. I'm pretty sure they're made by the same manufacturer as EG4. The cheaper one can do it, in a solar > utility > battery priority mode. But depending on your solar panel and consistent power draw, I'd maybe use the solar > battery > utility mode. It'll let you set a point to switch from battery to utility, the highest at 95%. That way when your usage is below your solar generation, you can still use the solar to charge the battery. A bit more wear and tear on the battery, but even less solar wasted. Assuming you can handle the batteries only being at 95% if you have an outage. If your usage is less than your solar generation, could even set it lower. I've been looking at something similar but different. My grid is fine, but I want to be able to use the batteries based on my time-of-use plan prices. I have less solar panels, but would want to charge my battery using grid power when prices are lower.

kshacker 2y ago

I do not want to fight with the utility or the insurance for such work, but this made me think: Can I set up something (I have a house) in my backyard + frontyard to just charge my EV? Catch the sun when it can, and then charge the car when connected. My PG&E bill says 56% of my usage is from midnight to 6 AM which is just EV + fridge. Although I pay a low rate on that, but imagine dropping half of your usage. I specifically pick out the EV as an example because by definition my system would never need to connect to the house or the grid, so I guess all I have is a disconnected battery (powerwall) to insure.

jonnycoder 2y ago
Yes very easy with a ground mount with 4 panels, a battery and inverter. I should write an article about it because I had planned to build something myself and keep all equipment outside and build a small wooden enclosure away from the house for it.
- thechao 2y ago
  My EV lives outside & right beneath the only safely accessible part of my roof to put solar on... so an explanation would be grand! My only issue is that I need solar->battery->car, as the car is at work 3/7 days...
yummypaint 2y ago
You might consider something on the opposite end of the spectrum, specifically net metering. If your grid connection is reliable, it's even more economical to get a solar system without batteries that feeds the grid. Where I'm located people pay the difference between the two without regard for when the power was generated or consumed. It also means your system is more efficient because there are no battery losses.
- mcbishop 2y ago
  Net metering is no longer available in PG&E territory.

winter_blue 2y ago

It sounds like the author of this piece lives in a jurisdiction without net metering. (The UK, perhaps?) If you have net metering, being able to push power back into the grid is a major plus.

Toutouxc 2y ago
It’s also a major pain in the ass in places where the grid isn’t exactly prepared for that. My parents are allowed to sell power from their EV installation. Their neighbor, who built a much smaller one a few months later, got denied.
FireBeyond 2y ago
I pity the poor linemen if you hook this contraption to feed back into the grid.
epistasis 2y ago
The bigger factor is that he's renting, and therefore whether the jurisdiction has net metering or not doesn't matter. But he's in San Francisco and California does not have net metering. I've been considering doing something like this as any grid-tied system is about $3/W for power, plus $500/kWh for storage. But an off-grid system done on your own is about $0.60/W plus $200/kWh for storage.
- winter_blue 2y ago
  Wow, California’s NEM 3.0 seems absolutely horrible. I hope it gets repealed.

pbnjay 2y ago

As someone living in NC and paying only $0.09/kwh, that $0.55/kwh in SF is just nuts to me! This setup has a 12 year payoff here...

worstspotgain 2y ago
The rate schedules are complex. I'm paying ~$0.43/kWh, itemized as $0.13/kWh generation (Clean Power SF) and $0.30/kWh distribution (PG&E). If you use very little on the residential schedule I think it can drop pretty low, probably around $0.15/kWh.
- pbnjay 2y ago
  My power is resold by the city so they don’t break it out, but a nearby county is 4.55c per kWh distribution charge and 5.96c per kWh generation charge.
- danans 2y ago
  > If you use very little on the residential schedule I think it can drop pretty low, probably around $0.15/kWh. The lowest price on the PG&E tiered rate plan E1 (implied by the words "If you use very little ...") is $0.42/kWh. Even the most variable rate EV2A plan has an off-peak price of $0.35/kWh. I don't see any way to get a price of $0.15 kWh.
  - worstspotgain 2y ago
    I stand corrected, it's been a while since I last looked at rates. I think the ~$0.15/kWh I remembered was from SVP in Santa Clara, not PG&E. https://www.siliconvalleypower.com/residents/rates-and-fees https://www.siliconvalleypower.com/residents/rates-and-fees
    - worstspotgain 2y ago
      BTW, the actual lowest rates for SF are closer to ~$0.26/kWh, and may be lower during the winter months at the lowest usage tier ("below baseline.") https://www.pge.com/assets/pge/docs/account/alternate-energy-providers/cleanpowersf_rateclasscomparison.pdf https://www.pge.com/assets/pge/docs/account/alternate-energy... I can't work it out exactly without doing more research than is worth. As I said, the schedules are complex, maybe someone more versed in this can chime in. Hopefully SF will finally manage to force PG&E to sell it the city's grid. I doubt it will lead to rates as low as Santa Clara's, though. https://sfpuc.org/about-us/news/its-high-time-san-francisco-buy-pges-grid-city https://sfpuc.org/about-us/news/its-high-time-san-francisco-...

millebe 2y ago

This is dangerous and illegal everywhere in the United States. DO NOT DO THIS! All 50 states have adopted NFPA 70, the National Electric Code, and the linked article shows a bunch of things that absolutely DO require a permit and would absolutely FAIL to be approved: First and foremost, running bare high voltage DC wires through an open window is in violation of a pile of building codes and very dangerous. The linked solar panels have an open circuit voltage of 64.8V, so with four of them in parallel there can be 260V of direct current. This can and will kill you, especially if you touch it in such a way where muscular tetanus prevents you from releasing the cable. Electrical extension cords are intended to be temporary, and the article's use of them violates a bunch of codes. Here are some of the relevant ones: 400.10 Uses Permitted (A) Uses Flexible cords and flexible cables shall be used only for the following: (1) Pendants. (2) Wiring of luminaires. (3) Connection of portable luminaires, portable and mobile signs, or appliances. (4) Elevator cables. (5) Wiring of cranes and hoists. (6) Connection of utilization equipment to facilitate frequent interchange. (7) Prevention of the transmission of noise or vibration. (8) Appliances where the fastening means and mechanical connections are specifically designed to permit ready removal for maintenance and repair, and the appliance is intended or identified for flexible cord connection. (9) Connection of moving parts. (10) Where specifically permitted elsewhere in this Code. (11) Between an existing receptacle outlet and an inlet, where the inlet provides power to an additional single receptacle outlet. The wiring interconnecting the inlet to the single receptacle outlet shall be a Chapter 3 wiring method. The inlet, receptacle outlet, and Chapter 3 wiring method, including the flexible cord and fittings, shall be a listed assembly specific for this application. 400.12 Uses Not Permitted Unless specifically permitted in 400.10, flexible cables, flexible cord sets, and power supply cords shall not be used for the following: (1) As a substitute for the fixed wiring of a structure (2) Where run through holes in walls, structural ceilings, suspended ceilings, dropped ceilings, or floors (3) Where run through doorways, windows, or similar openings (4) Where attached to building surfaces Exception to (4): Flexible cord and flexible cable shall be permitted to be attached to building surfaces in accordance with 368.56(B). (5) Where concealed by walls, floors, or ceilings or located above suspended or dropped ceilings Exception to (5): Flexible cord and flexible cable shall be permitted if contained within an enclosure for use in Other Spaces Used for Environmental Air as permitted by 300.22(C)(3). (7) Where subject to physical damage 400.17 Protection From Damage Flexible cords and flexible cables shall be protected by bushings or fittings where passing through holes in covers, outlet boxes, or similar enclosures. You absolutely cannot and should not run bare wires through a window. This manages to violate basically all of Chapter 3 of the NEC: 300.3 Conductors (A) Single Conductors Single conductors specified in Table 310.104(A) shall only be installed where part of a recognized wiring method of Chapter 3. 300.4 Protection Against Physical Damage Where subject to physical damage, conductors, raceways, and cables shall be protected. 300.6 Protection Against Corrosion and Deterioration Raceways, cable trays, cablebus, auxiliary gutters, cable armor, boxes, cable sheathing, cabinets, elbows, couplings, fittings, supports, and support hardware shall be of materials suitable for the environment in which they are to be installed. 300.11 Securing and Supporting (A) Secured in Place Raceways, cable assemblies, boxes, cabinets, and fittings shall be securely fastened in place. 300.12 Mechanical Continuity — Raceways and Cables Raceways, cable armors, and cable sheaths shall be continuous between cabinets, boxes, fittings, or other enclosures or outlets. 310.10 Uses Permitted (C) Wet Locations Insulated conductors and cables used in wet locations shall comply with one of the following: Be moisture-impervious metal-sheathed Be types MTW, RHW, RHW-2, TW, THW, THW-2, THHW, THWN, THWN-2, XHHW, XHHW-2, or ZW Be of a type listed for use in wet locations (D) Locations Exposed to Direct Sunlight Insulated conductors or cables used where exposed to direct rays of the sun shall comply with (D)(1) or (D)(2): Conductors and cables shall be listed, or listed and marked, as being sunlight resistant Conductors and cables shall be covered with insulating material, such as tape or sleeving, that is listed, or listed and marked, as being sunlight resistant Both the solar panels and the inverter are listed products and are required to be installed in accordance with their listings. In particular, this means they must be permanently fastened to the structure in the manner of the manufacturer's instructions. 110.3 Examination, Identification, Installation, Use, and Listing (Product Certification) of Equipment (B) Installation and Use Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling. The solar panels must be fastened to the structure in a way that resists wind and weather loads. There are entire sections of the NEC and various IBC codes devoted to this. Other various code sections that this would fail: 110.8 Wiring Methods Only wiring methods recognized as suitable are included in this Code. The recognized methods of wiring shall be permitted to be installed in any type of building or occupancy, except as otherwise provided in this Code. 110.12 Mechanical Execution of Work Electrical equipment shall be installed in a neat and workmanlike manner. 110.13 Mounting and Cooling of Equipment (A) Mounting Electrical equipment shall be firmly secured to the surface on which it is mounted. Wooden plugs driven into holes in masonry, concrete, plaster, or similar materials shall not be used. 110.26 Spaces About Electrical Equipment Access and working space shall be provided and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment. (A) Working Space Working space for equipment operating at 1000 volts, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized shall comply with the dimensions of 110.26(A)(1), (A)(2), (A)(3), and (A)(4) or as required or permitted elsewhere in this Code. (B) Clear Spaces Working space required by this section shall not be used for storage. When normally enclosed live parts are exposed for inspection or servicing, the working space, if in a passageway or general open space, shall be suitably guarded. (E) Dedicated Equipment Space All switchboards, switchgear, panelboards, and motor control centers shall be located in dedicated spaces and protected from damage. (1) Indoor Indoor installations shall comply with 110.26(E)(1)(a) through (E)(1)(d). (a) Dedicated Electrical Space. The space equal to the width and depth of the equipment and extending from the floor to a height of 1.8 m (6 ft) above the equipment or to the structural ceiling, whichever is lower, shall be dedicated to the electrical installation. No piping, ducts, leak protection apparatus, or other equipment foreign to the electrical installation shall be located in this zone. (2) Outdoor Outdoor installations shall comply with 110.26(E)(2)(a) through (c). (a) Installation Requirements. Outdoor electrical equipment shall be the following: (1) Installed in identified enclosures 110.27 Guarding of Live Parts (A) Live Parts Guarded Against Accidental Contact Except as elsewhere required or permitted by this Code, live parts of electrical equipment operating at 50 to 1000 volts, nominal shall be guarded against accidental contact by approved enclosures or by any of the following means: (1) By location in a room, vault, or similar enclosure that is accessible only to qualified persons. (3) By location on a balcony, gallery, or platform elevated and arranged so as to exclude unqualified persons. (4) By elevation above the floor or other working surface as follows: A minimum of 2.5 m (8 ft) for 50 volts to 300 volts between ungrounded conductors (B) Prevent Physical Damage In locations where electrical equipment is likely to be exposed to physical damage, enclosures or guards shall be so arranged and of such strength as to prevent such damage.

Cheer2171 2y ago

> It's not wired into the meter, doesn't require a permit, etc. This is 100% a fire hazard and would get your home insurance voided.

valianteffort 2y ago

You can buy 256Wh battery banks for around $150 now. You can pair them with a timer for charging/topping off at night when electricity is cheap. They even accept solar input. Throw one in every room and between appliances like the fridge or oven. Now you have a UPS for your whole house and the cheapest energy rates throughout the day.

epistasis 2y ago
Do those have an inverter built in? If not, at $600/kWh very pricy compared to what this guy used at $190/kWh for batteries, or $360/kWh including the inverter: https://www.amazon.com/dp/B08G81TKC6?ie=UTF8&th=1&linkCode=sl1&tag=gridlesskits-20&linkId=33ade7afc845a76a2271b39f1e6ed35a&language=en_US&ref_=as_li_ss_tl https://www.amazon.com/dp/B08G81TKC6?ie=UTF8&th=1&linkCode=s... Also, $190/kWh is so cheap. Its hard to believe how fast costs are falling for energy storage.
- ianburrell 2y ago
  If is he talking power bank, then big ones, usually called power stations, have inverters. But they can’t be used as UPS since they cut power when switching sources.
grobbyy 2y ago
My experience is that power banks and UPSes fail more often than my power. I keep a couple charged, but with nothing plugged in. I sometimes plug things in before a major storm, planned outage, or after an unplanned one.
- smeej 2y ago
  This is funny to me because mine just died unceremoniously during a snowstorm and it made me realize there should really be a testing cycle built in.
xyzzy123 2y ago
Hm fridge sure, but oven? 256Wh is going to power an electric oven for like, 5 minutes. Doesn't seem useful.

happytiger 2y ago

What’s the status in insurance for this thing? Generally this doesn’t seem like it would be covered under renters insurance. I can’t imagine a landlord in existence that wouldn’t throw a fit about something like this.

cameldrv 2y ago

All of the code/safety/landlord issues notwithstanding, the price is pretty incredible. If I plug my address into the PVWatts calculator, given the insane price increases from PG&E over the past few years, the payback period is one year. Beyond the fantastic economics, you're getting a decent emergency backup system that should cover at least your fridge, lights, and various electronics.

deeth_starr_v 2y ago

This reminds me of the time when I built a battery stereo power amplifier and then only used it a few times because I didn’t want to risk burning the apartment complex down. It was fun building it though.

magicbuzz 2y ago

The all-in-one 3kW inverter/controller that he uses is for 110V AC output (using the 48V battery). In the article he linked to, the system uses an EG4 3000EHV-48 that also outputs 110V AC. Are there equivalent all-in-ones that would provide 230/240V AC for use in Australia/New Zealand?

avar 2y ago
If you search for the manufacturer shown (PowMr) it looks like they make both 110v and 220v variants. This looks to be the same or similar product for 220v: https://a.aliexpress.com/_EwlP4Cf https://a.aliexpress.com/_EwlP4Cf
- mcbishop 2y ago
  I think this is single phase. 230V is a common single-phase voltage outside North America.
mcbishop 2y ago
I don't know of a 3kW inverter that outputs split phase. But you could get the higher-rated EG4 6000XP.
- Scoundreller 2y ago
  AU/NZ 240V wouldn't be split phase

threemux 2y ago

The quality of the components in this system is suspect. Check out Mobile Solar Power/ Will Prowse for unbiased, in depth reviews for this stuff

selfie 2y ago

How is self install possible if you are not a licensed electrician. Something like this could shock someone if not earthed properly, for example.

ricardobeat 2y ago

Hmm.. I wouldn't trust that "2,500W power distribution strip", or the extension cord itself, to actually be safe when you have a fridge, living room appliances and the induction cooktop pulling 1.2KW all at once. Fire waiting to happen.

chgs 2y ago
Do US cables not have appropriate fuses? If it’s a 10A cable then have a 10A fuse. Pull more than that and the fuse goes.
- ricardobeat 2y ago
  Guess you're from the UK? I think it's one of the only places in the world that does that. No, usually not, though better power strips will have one. But you don't need to go over the specified amps to cause a fire, there are multiple places that could overheat - extension cable, connections, solder points - while still being under the fuse rating if this thing is running at max power for a long time. The main job of a fuse is to protect against power surges / short circuits.
- Havoc 2y ago
  That's only necessarily in the UK because of the ring circuits https://en.wikipedia.org/wiki/Ring_circuit https://en.wikipedia.org/wiki/Ring_circuit
  - chgs 2y ago
    Sounds like it’s neccersary in the us too if you have cables rates at lower power than the circuit. I have lights with cables rated at well under 3A, they plug into the same outlet that a 10A cable can plug into. How do you stop a fault which draws 7A?

asdefghyk 2y ago

About under rated extension cords. My question is if in a house a person plugs in a under rated extension cord into a normal powerpoint and connects equipment to the other end, such that the current exceeds the extension cords current rating , and a FIRE results, would the insurance company pay??? ( ie this is in a house without any of the this DIY solar. cables or battery etc) . would be interesting question.

zo1 2y ago
No idea of the specifics. But a good heuristic to go off of is to assume that no they won't pay out if they can find anything that is remotely plausible to have been the cause or contributing factor.

choilive 2y ago

Wow... This should be added to the FAQ's under "Whats the catch?": At least a dozen code violations that risks burning down your/your landlord's property, serious injury or worse - loss of life - and opens yourself to VERY large liabilities. A more proper way to do this would be to have one self contained outdoor box rated to contain high energy batteries, have your inverter and PDU as part of that package and then plug your the panels to that. When you have a power outage go out and grab your backup battery box. This eliminates the bulk of the issues. Although, that raises the obvious solution that you could just spend a bit more money and get one of those self contained "battery generators", which have been properly engineered and designed, and are also pretty portable. Another thing I would add is adding some sandbags to the solar panels so that they don't fly off the roof in a high wind scenario. Theres a reason why when doing a rooftop installation code will specify this if not being directly bolted. (Technically a structural engineer will need to do a load calculation, but for this size of install the risks are minimal compared to the risks inherent in the rest of the system)

turtlebits 2y ago

Forget the landlord (who is already unlikely to give roof access, let alone run electrical wires outside), this immediately fails the WAF (wife acceptance factor) due to the hideous cable install.

stbenjam 2y ago
I know right? I love the caption on one of those photos about “relatively neat” cable runs.

ProllyInfamous 2y ago

You should absolutely NEVER place solar panels directly upon a roof as many of the linked website photographs demonstrate. Solar cells need ventilation on their undersides, and without it will rapidly be damaged (i.e. become more inefficient). Long-term, water trapped underneath may encourage shinglerot.

anonymousiam 2y ago

Nice Project! I did a similar project in 2003, but obviously the technology has improved a lot since then. I've previously posted some details here: https://news.ycombinator.com/item?id=36000824 https://news.ycombinator.com/item?id=36000824 The thing that stood out to me about this project was the lack of any hardware to secure the panels to the roof, which is absolutely necessary to prevent wind damage.

35mm 2y ago

Any tips for going through doors with the cabling?