14 ms·

I made my blog solar-powered, then things escalated

307 points by jandeboevrie 4y ago

spraveenitpro 4y ago
[dead]
bar000n 4y ago
east facing window gets light in the morning, not afternoon/evening…
- cfn 4y ago
  That's what I thought throughout the article. I wonder if it is a typo or the author is confused about East and West?
  - rmetzler 4y ago
    If you search for east on the page, it comes up 4 or 5 times. That doesn’t seem to be a typo. And since the time is written in 24h notation, I also don’t think there is a typo there.
- blkhawk 4y ago
  in flat country with no trees and other houses around yes. all it takes is a shadow and you might get more power in the afternoon from the white wall of a house across the street.
  - blkhawk 4y ago
    I just checked - the panel on my toy system faces directly east but only gets about 2ish hours of non-optimal light a day (between 10ish and 12ish - after that there are chimney shadows) due to houses being in the way. This is peak in summer - for the rest of the year i get less because the sun is lower longer.
- ajuc 4y ago
  It's funny seeing this mistake crop up once in a while, when in my native language "east"="sunrise" and "west"="sunset" :) You distinguish between them with prepositions ("in sunrise" vs "at sunrise").
- louwrentius 4y ago
  I mixed east and west, now fixed in the blog.
newaccount74 4y ago
It seems that a major cost of solar installations is the inverter. Power electronics that generate >100W AC power are big and expensive. Now that more and more devices use USB-C PD for power, I wonder whether it would be possible to forego the AC inverter, and just power everything with small USB-C power supplies that have 12V input and can be powered directly from the battery. Or maybe you could use a 110V inverter instead of a 230V inverter? Switched mode power supplies usually accept either.
- blkhawk 4y ago
  yes - my small inverter was 30EUR - its only capable of delivering about 180W. That was a significant portion of the total system cost for my toy system (with a 180W panel).
- amatecha 4y ago
  Yeah, inverters are pretty inefficient too. I've got a 12v battery and I power some stuff directly, and then a couple things from a 12v->5v buck converter. So far so good, even though the applications are limited. My setup is ultra-humble though lol (I don't even have a solar charge controller yet!)
- bityard 4y ago
  12v DC power systems is a sub-niche in both the RV and ham radio communities. I know of someone locally who has most of his house on 12v lighting and some appliances, to be able to take advantage of solar without the high expense and hassle of a grid-tied system.
- goodpoint 4y ago
  Yes. The setup in the article is pretty inefficient.
- _heimdall 4y ago
  The really big costs start to pipe up with batteries if you want the system to be functional at night and on rainy days Inverters aren't cheap, but as your inverter size goes up your battery capacity likely scales even faster to account for times when you don't have much sun for 2-3 days. Hopefully that'll change soon! Lifepo4 batteries are the best we have on the market today, but they're not cheap and still require a lot of hard to find natural resources to produce
blkhawk 4y ago
I run a similar toy system with a 180w panel and it makes about 110wh a day on an average from march to October - due to a similar bad position the monitoring plug would use more power than the panel makes the rest of the year :P It runs an inverter and offsets my electricity use. I plan adding a battery this year but my MPPT charger has been stuck in Hannover for 3 weeks now - I suspect a customs issue.
quaintdev 4y ago
> Although that sounds like a very light load, if you run it for 24 hours, it's equivalent to using 84 Watts continuously for one hour. Its called 84 watt-hours and this is energy consumed in 24 hrs. 3.5 watts is energy consumption rate and is called as power(joules/sec). 84 Wh is not actually lot. I made a calculator for raspberry pi energy consumption https://tinyurl.com/nwu6sn4s https://tinyurl.com/nwu6sn4s
- walrus01 4y ago
  For a comparison, 50W doesn't seem like much, right? Maybe if you're older you had 50W incandescent light bulbs in your house. Normal thing. Let's say a WISP wanted to run a very basic off grid relay site with some radios that are 8-12W DC load each and a router that's 15W. Total around 50W 24x7x365. ((50 x 24 x 31)) / 1000 That's 37.2 kWh per month. You need a surprisingly large amount of solar panels to generate a reliable 45-50 kwH per month to refill a battery bank every day when the sun comes up, in November, December, January, February at latitude 45N or above. Like, really, a lot more than you might think. Four or more 370W 72-cell.
  - jakewins 4y ago
    PVwatts says a 4-module array of 370w panels, including AC losses, will produce about 100kWh in January at 45N FWIW
    - walrus01 4y ago
      That's assuming perfect sun exposure on a roof or ground moving with no shadowing at any time of the day and at the optimal tilt. Pvwatts says that usable energy from a 1480W system at 43.6N in Boise ID might be more like 77kWh a month in December, the shortest sunlight month of the year. An off grid system generally needs to be calculated to survive December. January will be a few percent better as days start getting longer. Realistically, to get through entire week long periods of snow and overcast, if I had a load that was 50kWh a month I would want a 75-80kWh a month predicted PV production system to make it worry free in December.
  - 4y ago
ThatPlayer 4y ago
> If you ever intend to build some kind of solar setup yourself, consider a 24 Volt or ideally an 48 Volt system to reduce currents and thus save on cabling cost. I sort of regret going with a 48V system because it prevents me from plugging in a lot of devices directly to the battery. I have a few USB-C PD fast charging modules I would want to use directly. Also a battery-to-battery charger such as an iCharger or ISDT product won't do 48V as input or output. Not a big deal if you just want to connect an inverter all the time. A more relevant issue may be that your solar panel's voltage will have to be > 48V. Actual voltage will depend on your MPPT charger. Victron seems to require battery voltage + 5V. Mine requires a minimal of 60V from the panels, so I have 3 24V panels wired in series, and cannot downsize. I think 24V would've been a good sweet spot. The USB-C PD modules only step-down, so they cannot output 19V with 12V power.
- jnsaff2 4y ago
  For off-grid setups (which I consider the OP's setup) I would also consider 24V. I would consider ElectroDacus [0] which would replace the need for an MPPT and a BMS for lithium batteries. So besides a panel, battery and inverter this is all you need. [0] - https://electrodacus.com/ https://electrodacus.com/
- louwrentius 4y ago
  > I sort of regret going with a 48V system because it prevents me from plugging in a lot of devices directly to the battery I think there are plenty of 48->12 volt DC-DC converters that will alleviate this issue.
  - asolidtime1 4y ago
    You can still have a 12-volt bus, but since you're not plugging directly into the battery you'll suffer some conversion losses (buck converters are generally 80 to 95 percent efficient, depending on the operating conditions and cost)
amatecha 4y ago
Tip to OP (I think they already have this idea, based on the post): when that lead-acid battery dies, replace it with a LiFePo4, which is substantially more efficient, lasts 3x as long, has a higher energy density, provides a usable voltage far further into its discharging %, etc. etc... A couple pages that describe the differences linked below... tl;dr if you are starting a solar battery project, LiFePo4 is the clear choice by far, unless you're going for the absolute cheapest possible build due to immediate budget constraints. https://www.canbat.com/a-detailed-comparison-of-lead-acid-batteries-and-lithium-iron-batteries/ https://www.canbat.com/a-detailed-comparison-of-lead-acid-ba... https://www.power-sonic.com/blog/lithium-vs-lead-acid-batteries/ https://www.power-sonic.com/blog/lithium-vs-lead-acid-batter...
- walrus01 4y ago
  I don't disagree with you but lifepo4 have a high upfront one time purchase cost for something equivalent in capacity to a 12V 100Ah AGM, like easily $450-500 per unit or more. They do pay for themselves over time with their much greater longevity. Might be more than the blog owner wants to spend for what is just a fun hobby project. There are some 3U rackmount size nominal 48vdc 50Ah lifepo4 (approx 4.8kWh capacity) with built in bms and LVD you can get from china now.
  - amatecha 4y ago
    Yeah, there's def the upfront cost, which not everyone can justify. Though, at the same time, a lower-amp-hour battery can provide as much actually-usable energy as a higher-amp-hour-rated SLA battery (so you could purchase a LiFePo4 battery with a lower amp-hour rating than the equivalent SLA battery but still get the same run time). I wouldn't know how much lower you can go though offhand.
  - sgt 4y ago
    With lead acids you just have to make sure you don't go below 40% charge. They don't tend to like that. The deep cycle ones are a bit better but I've experienced them deteriorating quickly too once you go too low. The other disadvantage is that they are quite heavy and might end up taking up lots of space. I'm personally still using lead acid, but with plans to go LiFePo4.
deleted 4y ago
[deleted]
YarickR2 4y ago
So; how much did the whole setup cost ?
- nivenkos 4y ago
  It says 2000 EUR at the bottom.
choeger 4y ago
Cool project. I think we really need some free software sensor/controller libraries/frameworks for solar setups. The reason is that here in Germany, and presumably elsewhere in Europe, these "balcony powerplants" are taking off. You are allowed to plug up to 600W (soon up to 800W) into your socket without further trouble. But unfortunately, most people will waste a lot of energy this way. Very few people will have permanent usage of 100W or more. Instead, consumers like refrigerators will turn on and off multiple times per hour. So the ideal setup would consist of one or more load-measuring sensors, a smallish long-lasting battery (LiFe?), some oversized panels (say up to 2kW) and a converter that hooks everything up. The controller should ensure that you feed power into your grid only when you need it and otherwise charge your battery. I think that such a setup could easily get you 4kWh/day of consumption in spring and summer. And potentially still 1kWh during most winter days.
- tcfhgj 4y ago
  It's not wasted energy. The country (perhaps even the continent) still benefits from it by having to burn less gas and coal
  - _heimdall 4y ago
    With regards to the wasted energy that is potentially made by the panel but unused, that doesn't offset any other power production since the power wasn't going to be used anyway
    - tcfhgj 4y ago
      Of course the power is used. It's in the grid, and every power source has to be compensated by a power sink, otherwise you have instable grid = blackout if the deviation is too big
      - _heimdall 4y ago
        Are you assuming the panels are grid-tied? I may have missed that in the article, the setup sounded very off-grid to me at which point the power potential is lost if not used immediately.
ofisboy 4y ago
Hey peeps. Sorry for hijacking the topic. I also live in the Netherlands and my backyard perfecty faces south, which means i get huge sunlight on that side of the house. But because my house has a glass-roofed extension on the ground floor, all solar companies i spoke say they can’t install panels on the roof because they can’t build scaffold on that side. Here’s an image to explain a bit better. [image](https://imgur.com/a/WE1Qojf https://imgur.com/a/WE1Qojf) So the red area is the glass-roofed extension on the ground floor. And blue area is the space on the roof that solar panels should be placed. Green is a dormer (which they said they can’t also put panels on top) I was wondering any dutchies might know a solution/advice a company about this? Also is there any portable panels that i can put on top of the glass extension? Thanks
- hellweaver666 4y ago
  I replied about this on another comment but have a look at "We Do Solar" their product is designed for installing on balconies but I guess there is nothing to stop you installing it where ever you like! (You might just need to add a bit of a frame to support them?)
  - jacquesm 4y ago
    Beware, those tend to be ballasted, for mounting on a light roofing structure you really want something that isn't ballasted.
- bartislartfast 4y ago
  not in NL but my parents have the same problem - glass roofed extension stops the installation I dont understand why they can't just access the roof from the other side, climb over the apex and down. They walk all around on the roof once they're up there, does it really matter which side they climb?
- kippel 4y ago
  It isn't clear from the picture and I guess it's too obvious, but if you have a neighbour, they can climb from their roof. That's how my neighbour got his installation done. I have seen them do more complicated installations (4 floors scaffolding + crane to lift panels), I don't know why they refuse that one.
winrid 4y ago
The other problem is the 3.5 watt draw, or 600ma at idle, of the PI4B. If you used a PI Zero with an ethernet expansion board this goes down to 100ma at idle. 6x less. You still get 1ghz cpu and 512mb of ram. I could even run django and postgres on that. Certainly you don't need gigabytes of ram to run the blog. :)
- bullen 4y ago
  The Raspberry 2 (original ARMv7 not underclocked Raspberry 3 ARMv8) is the best low power server. 1W idle and 2W 100% (6x more perf. than Raspberry 1 = Zero with Eth.). They saturate the SD card SPI almost to the byte/second. 32-bit is enough forever, specially when you only have 1GB, but I'm staying on 32-bit on my 8GB RPi 4 too, because 4GB per process is enough when you also need the OS to have ample RAM. If you are lucky enough to have some ARMv7 RPi 2 and/or Rpi 4 8GB, they will be priceless for eternity.
  - olabyne 4y ago
    The RPi 2 is the unpopular kid of the familly, I don't know why. Maybe it got erased pretty quickly by the Pi3 performances and Wifi capabilities. The thing I don't understand tho, is why they didn't chose this Soc for the Pi Zero original, instead of using the already decade-old ArmV6 CPU.
    - bullen 4y ago
      They can't, the RAM was external which wouldn't fit on the one sided Zero. Thus why they bounded the 512MB ram in the package for Zero 2. Physical limits are now everything you'll see until the end of time. 8GB is the largest RAM you will ever get in one chip. 1TB is the largest Micro SD. Etc.
  - roeles 4y ago
    A Pi Zero can go down to 0.5W idle. The Pi Zero 2W should also be good, but is very hard to obtain right now.
shreddit 4y ago
Can someone recommend a brand of solar panels or a retailer, preferably in europe?
- mgraupner 4y ago
  It does not really matter, they are basically all the same. Only thing to watch out is that they should be build with half-cell technology and monocrystalline (which almost all of them are, technology does not differ that much in solar panels). 400 W Panels are pretty much standard.
- bartislartfast 4y ago
  I think most countries in Europe would have local solar panel sellers. I'm in Ireland which is usually pretty bad for availability of things, (for example, there's no amazon.ie - we have to buy from UK or DE) and even here we have solartricity.ie, solarstore.ie and several others. Longi panels are what I got, if you want a recognisable brand name Panasonic also do them.
archi42 4y ago
For those thinking about replicating this: Victron is really popular because it's extendable and the management interface is reasonably open, but the zoo of required devices makes the costs explode quickly. Maybe look at Deye instead. I'm running a 12kW unit (they're available smaller) with a 48V battery. The software is in poorly translated to English, firmware updates are made by the manufacturer remote on request and it has no shadow management (meaning it might end up on a local maximum in the MPPT, not the global maximum) - but the unit cost me about 3000€ with 10yr warranty instead of the >7000€ for an equivalent zoo of Victron parts. Of course it can do black starts from PV or battery, and act as a UPS on a secondary output. Pulling data locally can be done using a RS485 modbus interface; so I open my firewall only for firmware updates. The 3.6kW single phase unit (SG05LP1) can be had for less than 1300€. A 5kW three phase unit is only a little bit more expensive, but I'd worry about standby consumption in low power scenarios with only a few modules (mine hogs 80W, but a three phase Victron setup does so as well). These are string inverters, so you need more modules for them to reach their start up voltage, and then some more to put them into the MPPT zone. The 1 phase starts at 125V and the MPPT tracker works with 150-425V, the 3 phase units 160V & 200-650V respectively. When I browsed the market there were other offerings from other brands with 90V start up; but be careful to get a unit that's legal to connect to the grid IF you want to have grid fall back (here in Germany, Victron and Deye are legal - at least the parts I looked at. But you will always need a electrician with a concession to register them with the grid company. Some people don't care and just setup their systems though). Important: The voltages depend on the chosen PV module; mine are in the 40V per module ballpark, but iirc I might maybe have seen up to 60V? So for the 3.6kW unit you'd want at least 3 or 4 modules.
- madaxe_again 4y ago
  Not sure what zoo of parts you’re referring to? I have two multiplus 5kva 48v, a bmv-712, a venus gx, and a pair of their biggest MPPTs - and for our pretty large install it shook out at about €4,500. Without the redundancy, it would have been more like €2,500.
  - archi42 4y ago
    Don't get me wrong, the Victron systems are nice & I envy their great traits I've praised in sibling comments. But your system doesn't compare on the power specs. There is no exact equivalent for the Deye with Victron. The Deye can do 15.6kWp solar, split over 2 MPPT. The topology is such that one MPPT can do 15kW while the other does 0W (I did not believe this, but I've talked to the manufacturer and it's indeed correct). The inverter can output 12kW AC, or draw that much for charging the battery. If your load is not balanced well, there is a video of someone testing it with 12kW sustained output on a single phase (this is only useful for a select few maniacs though; I'm not one of these). And if the 12kW is not enough, you can put them in parallel (like with Victron). I deleted my notes on the Victron setup, but this is something similar to what I was looking at (about Sept 2022): 3x Multiplus 48/5000 on the AC/DC end for full three phase setup (back then 1700€ each, now 1300€) - mind those can really "only" push 5000VA or 4000W at 25degC. Our roof would be 1x MPPT RS 450/200 (pretty stable at 1800€), the string in the garden 1x 450/100 (1200€ in Sept, 1000€ now). A RPi plus USB adapters and PSU and sturdy case for VenusOS (or a GX unit) would be close to 100€ extra, also add additional cables and the necessary busbars (dunno, 200€?). For a three phase that's 7000€ today, or 8400€ in September. Of course that's just one way of building a system, and Victron is amazingly flexible - and with my 14kWh battery two multiplus would probably have been enough (caveat emptor: no idea if my grid operator would have accepted 2x5kVA or rejected it due to the inbalance). Lots of people use a SmartShunt or Lynx, these also add to the costs of a Victron system. Why zoo: The footprint of the Victron 3x MP and 2x MPPTs is nearly 0.9m²; add busbars and other periphals, and you're easily at 1m². Plus, each device needs some clearance due to the heat. The Deye is one unit with 0.3m² footprint. This is also nice.
wkjagt 4y ago
Being in the Netherlands makes this very challenging indeed. I am from the Netherlands but don't live there anymore. I came to visit family in December a couple of years ago instead of the usual summer trip and I had forgotten how incredibly gloomy it gets. Short days, dark, low hanging clouds much of the time. Not much solar energy on those days.
- jacquesm 4y ago
  Indeed, December here we made all of 85 KWh, whereas the peak day in April so far produced 68 KWh and I fully expect summer days to be much better than that still. So that's a ratio of 1:30 between winter and summer! The worst day in April so far was 13 KWh, the worst day in December was 0.3 KWh. So no matter what you do, you'll end up using power from the grid. And no realistic battery system is going to give you three months worth of storage. At best you'll have two days worth, maybe three.
jb1991 4y ago
> my balcony is facing east. This means it only receives direct sunlight from 16:00 onward during spring and summer. I’m confused. The sun rises in the east. By late afternoon it would not be directly shining on an east-facing balcony, would it? The most sun would be in the morning on that east side, I would think.
- deleted 4y ago
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- louwrentius 4y ago
  I'm mixing east and west, sorry, I'm going to update my article.
hankman86 4y ago
Did you ever work out how much energy was expended to manufacture and transport the parts? Chances are that with solar panels facing west in a place like The Netherlands, it will take a long time to come out on top with your carbon footprint. I reckon that the most energy-efficient setup for your blog would be a hosted solution. Data centres are already optimised for low energy use. And some cloud providers have committed to become carbon neutral. Lowering your overall household electricity use would be a more effective way to lower your carbon output.
- mgraupner 4y ago
  I also think that this setup will not be worth it ecologically or economically.
- trabant00 4y ago
  And I bet his hardware saturation is low too, making it an even worse use of resources compared to shared hosting in a data center that uses bin packing or live migrating VMs or whatever. Because in the end you care about resources used for the actual work done, not the work capacity of the hardware. While it doesn't make much difference at this scale and it is a valid experiment to learn about solar power, it is telling of the general view about energy and environmental impact. People equate solar or wind or electric vehicles with green when the devil is always in the details.
- bartislartfast 4y ago
  Did you read the article? Quote: > It's fair to say that my experiment isn't rational because of the sub-optimal solar conditions. Yet, I'm unreasonably obsessed by solar power and I wanted to make it work, even if it didn't make sense from an economic or environmental perspective2. This is just a fun experiment
wanabananascene 4y ago
[flagged]
jve 4y ago
I am less of a DIYer than the author and safety was always a priority... good author knows about amps, cable sizes, etc. But charging lead acid battery inside a house? I've stumbled across warnings where it says they must be charged in a well ventilated area. Anyone care to chime in, for the safety of author? https://www.ccohs.ca/oshanswers/safety_haz/battery-charging.html#:~:text=When%20leac%2Dacid%20batteries%20are,number%20of%20batteries%20being%20charged https://www.ccohs.ca/oshanswers/safety_haz/battery-charging.....
- drzaiusx11 4y ago
  Sealed lead acid (SLA) batteries only outgas an appreciable amount when overcharged/overdischared. Vented instead of sealed types can also be used indoors but require their own ventilation system. The majority of UPS systems use SLA batteries indoors.
  - jmnicolas 4y ago
    But is it safe to inhale the gases?
    - chucksta 4y ago
      Its Hydrogen, the concern is explosion https://www.ccohs.ca/oshanswers/safety_haz/battery-charging.html https://www.ccohs.ca/oshanswers/safety_haz/battery-charging....
      - moffkalast 4y ago
        > Overcharging a lead acid battery can also lead to the generation of hydrogen sulfide, which can cause harm to workers if exposed. The concern is also the toxicity of H2S. Most SLA chargers are poorly designed and will overcharge any battery that isn't in mint condition.
        drzaiusx11 4y ago
        Agreed that cheap "trickle" chargers with unregulated voltage can cause overcharging if left on for too long (days to weeks on larger batteries, as their current is usually under 1A) Better to invest in a "float" charger with a regulated output and automatic shutoff. As with many subjects, if you go the cheapest route you pay with time or safety risk.
Havoc 4y ago
>Suddenly you realise that making the background on all monitors black saves ~20 Watt. Depends on panel type - some are lower @ white
- itsyaboi 4y ago
  Curious, do you have any examples of monitors like that? Less light and lower brightness reducing power consumption is intuitive, the inverse less so.
  - Havoc 4y ago
    Some LCD screens. It's pretty marginal though https://www.quora.com/Does-a-white-background-use-more-energy-on-an-LCD-than-if-it-was-set-to-black https://www.quora.com/Does-a-white-background-use-more-energ...
mugiseyebrows 4y ago
If you only serve static files you can use Arduino (or better) MCU (it has lan shield) and decrease power consumption three times, and 18650 instead of car battery can perform better.
vrglvrglvrgl 4y ago
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prmoustache 4y ago
Wouldn't a small wind turbine make more sense in the Netherlands?
- nextlevelwizard 4y ago
  On a random balcony in a city? I don't know how efficient turbines are, but that doesn't sound very promising.
- joshuanapoli 4y ago
  I think that wind turbines are harder for DIY because they need to be mounted well above the roof height to get non-turbulent airflow.
- detaro 4y ago
  really small wind turbines are almost never worth it
- jacquesm 4y ago
  No, it wouldn't. The capacity factor for a small, unidirectional turbine in non-laminar flow is going to be somewhere between 0 and 15% depending on how lucky you are with the prevailing wind direction. Small turbines also tend to be quite noisy. There was a small unit that was sold by a Canadian solar/wind installer that was named the 'Whisper', but we privately called it the screamer (and it was one of the main reasons we ended up building our own turbine, all of the ones that were on the market were small, loud and inefficient because they were all fixed pitch).
  - dredmorbius 4y ago
    There's also the problems of mounting on a structure, let alone on an apartment building with limited exterior access (as with this case). Turbines vibrate, and over time can cause joints to weaken as nails are loosened. That's even without considering the disruption to laminar flow (e.g., full wind efficiency) caused by diverting wind-flow over a structure. Upshot is that if you do want a wind turbine and have a viable use-case, you'll still want a free-standing tower well clear of structures, trees, etc.
Proven 4y ago
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cr3ative 4y ago
I'm a little confused about the need for the inverter here. The SmartSolar can provide output the Pi can use. Why not just throw a 12v-compatible USB power supply on there? Going up to mains then back down to 5v seems inefficient. Am I missing something? edit: I'm wrong! My SmartSolar has "LOAD" output but OP's does not. Ref: https://www.victronenergy.com/solar-charge-controllers/smartsolar-mppt-75-10-75-15-100-15-100-20 https://www.victronenergy.com/solar-charge-controllers/smart...
- roeles 4y ago
  Still, there's the UUGEAR Zero2Go board that you might use to step down from 12v to 5V: https://www.uugear.com/product/zero2go-omini-wide-input-range-multi-channel-power-supply-for-raspberry-pi/ https://www.uugear.com/product/zero2go-omini-wide-input-rang...
  - asolidtime1 4y ago
    IMO, these types of listings (power supply for <insert popular development board>) prey on people who don't have a ton of EE knowledge. A pack of 10 2A buck-converter modules from Aliexpress will run you about $5
- pflanze 4y ago
  Why do you think the Pi is powered via the inverter? I can't see mention of this, and the picture of their setup shows the Pi being powered by a step-down from 12 V.
  - GoToRO 4y ago
    That picture is not his setup.
    - pflanze 4y ago
      I'm talking about the picture with the caption "the latest iteration of my solar setup". Maybe you tripped over the text "So I decided to build a new setup inspired by Will Prowse solar demo setups, which is pictured below:", which I understand as "So I decided to build a new setup, pictured below, which was inspired by Will Prowse solar demo setups:".
dom96 4y ago
I often wonder if wind power could be harnessed in a similar manner on a balcony. Anybody try this to power their blog or saw someone else do something similar? or is this simply unfeasible?
- _heimdall 4y ago
  Wind is tricky depending on where you live. In the US there are surprisingly few places where smaller consumer-grade windmills make sense. Its been a while so this may be off, but I want to say you need a consistent wind of something like 10-15mph for most turbines to be of any real use Even then, a 3000W turbine is usually best on something like a 30-50' tall pole In certain areas wind can be efficient, in most areas (at least in the US) solar is much easier to deal with and more reliable
pflanze 4y ago
I see a safety hazard with the exposed battery terminals (as shown in the picture "A 12 Volt 230 Ah lead-acid battery"). AFAIK, lead-acid batteries are less powerful than Li-ion/LFP but would probably still start a fire or give nasty sparks if something metallic falls onto the battery. (I'd be happy to be corrected.) > The drawback of a 12-volt system is the relatively large currents required to charge the battery and power the inverter. This requires thicker, more expensive cabling to prevent energy losses in the cabling. Arguably it's only for the discharging via the inverter that you need the thick cables, as otherwise they don't need to be thicker than the cables from the panels. (The current for charging could be much lower than the maximum discharge current.) -- Except if the MPPT steps down the voltage from the panels to the battery by a lot.
- louwrentius 4y ago
  See the footnotes.
foodoos 4y ago
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GoToRO 4y ago
Ditch the inverter and you are set.
- asolidtime1 4y ago
  Please read the article or at least look at the image of their setup; they only switch on the inverter occasionally to power their main computer and monitors
foodoos 4y ago
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xony 4y ago
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turtlebits 4y ago
You don't need an inverter if you're just using an rpi. You can get away with a cheap 12v car USB adapter. I do this for my off-grid wifi (rpi and 5g phone plugged into USB).
ccorcos 4y ago
It’s always frustrating to me to see an inverter in these setups. All of your digital devices actually run on DC current! Your computer, monitor, phone charger… Inverters consume energy just being on, whether current is being drawn or not. And they’re expensive! Without the inverter, a solar panel+battery setup is super simple and I’m curious to see a movement towards low-voltage circuits in homes. You can easily power all of the lights in your home with a solar panel connected to a 12v battery. Double in size and you can power your TV and router as well. This isn’t going to save you a significant amount of money though. It’s just interesting. Big ticket items like your water heater or air conditioner consume a lot more power and will probably need an inverter, etc.
- louwrentius 4y ago
  The key issue is that all my existing equipment is 230v. I would have to rebuy everything. If you need an inverter anyway for hvac, you have added complexity and no gains. Although not mentioned, I’m using 230v ikea fixtures with 12v led e27 bulbs wired to 12 volt, as you mentioned. Is indeed quite efficient, no inverter running.
  - ccorcos 4y ago
    Yeah, but the annoying thing (from an engineering elegance perspective) is that most of those appliances that are on 230VAC convert to 12-48VDC internally (e.g. TV/monitor, LEDs).
    - louwrentius 4y ago
      Yeah regarding those appliances 100% I see the inelegant solution. Imagine all new equipment below x watt would be required to have a 12v input in addition to 120/230
- kamranjon 4y ago
  I always thought it would be cool wire parts of your home using PoE (power over ethernet) if you had some solar panels and a battery bank.
muyuu 4y ago
I may be out of the loop with prices but 2000€ sounds like a lot for such a small setup. Maybe the tradeoffs of going smaller are worse than I thought, but for ~3500€ I got what I roughly estimate to be worth about 3x as much in generation and storage.
- 1123581321 4y ago
  I think that tracks. He seems to have spent several hundred on the panel, frame, wiring to his board and a right-sized battery. You would have incurred those per-watt expenses two more times. Most of the other costs to invert, switch source, and store power are fixed. He seems on track to build out his system even further, based on the intro, too, so he’ll probably catch up with you.
- louwrentius 4y ago
  The frames cost is 25%, which you wouldn’t have. Larger setups are often more efficient in price and performance. Going small is indeed expensive.
foodoos 4y ago
Magnets can generate energy.

307 points by jandeboevrie 4y ago

spraveenitpro 4y ago

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bar000n 4y ago

east facing window gets light in the morning, not afternoon/evening…

cfn 4y ago
That's what I thought throughout the article. I wonder if it is a typo or the author is confused about East and West?
- rmetzler 4y ago
  If you search for east on the page, it comes up 4 or 5 times. That doesn’t seem to be a typo. And since the time is written in 24h notation, I also don’t think there is a typo there.
blkhawk 4y ago
in flat country with no trees and other houses around yes. all it takes is a shadow and you might get more power in the afternoon from the white wall of a house across the street.
- blkhawk 4y ago
  I just checked - the panel on my toy system faces directly east but only gets about 2ish hours of non-optimal light a day (between 10ish and 12ish - after that there are chimney shadows) due to houses being in the way. This is peak in summer - for the rest of the year i get less because the sun is lower longer.
ajuc 4y ago
It's funny seeing this mistake crop up once in a while, when in my native language "east"="sunrise" and "west"="sunset" :) You distinguish between them with prepositions ("in sunrise" vs "at sunrise").
louwrentius 4y ago
I mixed east and west, now fixed in the blog.

newaccount74 4y ago

It seems that a major cost of solar installations is the inverter. Power electronics that generate >100W AC power are big and expensive. Now that more and more devices use USB-C PD for power, I wonder whether it would be possible to forego the AC inverter, and just power everything with small USB-C power supplies that have 12V input and can be powered directly from the battery. Or maybe you could use a 110V inverter instead of a 230V inverter? Switched mode power supplies usually accept either.

blkhawk 4y ago
yes - my small inverter was 30EUR - its only capable of delivering about 180W. That was a significant portion of the total system cost for my toy system (with a 180W panel).
amatecha 4y ago
Yeah, inverters are pretty inefficient too. I've got a 12v battery and I power some stuff directly, and then a couple things from a 12v->5v buck converter. So far so good, even though the applications are limited. My setup is ultra-humble though lol (I don't even have a solar charge controller yet!)
bityard 4y ago
12v DC power systems is a sub-niche in both the RV and ham radio communities. I know of someone locally who has most of his house on 12v lighting and some appliances, to be able to take advantage of solar without the high expense and hassle of a grid-tied system.
goodpoint 4y ago
Yes. The setup in the article is pretty inefficient.
_heimdall 4y ago
The really big costs start to pipe up with batteries if you want the system to be functional at night and on rainy days Inverters aren't cheap, but as your inverter size goes up your battery capacity likely scales even faster to account for times when you don't have much sun for 2-3 days. Hopefully that'll change soon! Lifepo4 batteries are the best we have on the market today, but they're not cheap and still require a lot of hard to find natural resources to produce

blkhawk 4y ago

I run a similar toy system with a 180w panel and it makes about 110wh a day on an average from march to October - due to a similar bad position the monitoring plug would use more power than the panel makes the rest of the year :P It runs an inverter and offsets my electricity use. I plan adding a battery this year but my MPPT charger has been stuck in Hannover for 3 weeks now - I suspect a customs issue.

quaintdev 4y ago

> Although that sounds like a very light load, if you run it for 24 hours, it's equivalent to using 84 Watts continuously for one hour. Its called 84 watt-hours and this is energy consumed in 24 hrs. 3.5 watts is energy consumption rate and is called as power(joules/sec). 84 Wh is not actually lot. I made a calculator for raspberry pi energy consumption https://tinyurl.com/nwu6sn4s https://tinyurl.com/nwu6sn4s

walrus01 4y ago
For a comparison, 50W doesn't seem like much, right? Maybe if you're older you had 50W incandescent light bulbs in your house. Normal thing. Let's say a WISP wanted to run a very basic off grid relay site with some radios that are 8-12W DC load each and a router that's 15W. Total around 50W 24x7x365. ((50 x 24 x 31)) / 1000 That's 37.2 kWh per month. You need a surprisingly large amount of solar panels to generate a reliable 45-50 kwH per month to refill a battery bank every day when the sun comes up, in November, December, January, February at latitude 45N or above. Like, really, a lot more than you might think. Four or more 370W 72-cell.
- jakewins 4y ago
  PVwatts says a 4-module array of 370w panels, including AC losses, will produce about 100kWh in January at 45N FWIW
  - walrus01 4y ago
    That's assuming perfect sun exposure on a roof or ground moving with no shadowing at any time of the day and at the optimal tilt. Pvwatts says that usable energy from a 1480W system at 43.6N in Boise ID might be more like 77kWh a month in December, the shortest sunlight month of the year. An off grid system generally needs to be calculated to survive December. January will be a few percent better as days start getting longer. Realistically, to get through entire week long periods of snow and overcast, if I had a load that was 50kWh a month I would want a 75-80kWh a month predicted PV production system to make it worry free in December.
- 4y ago

ThatPlayer 4y ago

> If you ever intend to build some kind of solar setup yourself, consider a 24 Volt or ideally an 48 Volt system to reduce currents and thus save on cabling cost. I sort of regret going with a 48V system because it prevents me from plugging in a lot of devices directly to the battery. I have a few USB-C PD fast charging modules I would want to use directly. Also a battery-to-battery charger such as an iCharger or ISDT product won't do 48V as input or output. Not a big deal if you just want to connect an inverter all the time. A more relevant issue may be that your solar panel's voltage will have to be > 48V. Actual voltage will depend on your MPPT charger. Victron seems to require battery voltage + 5V. Mine requires a minimal of 60V from the panels, so I have 3 24V panels wired in series, and cannot downsize. I think 24V would've been a good sweet spot. The USB-C PD modules only step-down, so they cannot output 19V with 12V power.

jnsaff2 4y ago
For off-grid setups (which I consider the OP's setup) I would also consider 24V. I would consider ElectroDacus [0] which would replace the need for an MPPT and a BMS for lithium batteries. So besides a panel, battery and inverter this is all you need. [0] - https://electrodacus.com/ https://electrodacus.com/
louwrentius 4y ago
> I sort of regret going with a 48V system because it prevents me from plugging in a lot of devices directly to the battery I think there are plenty of 48->12 volt DC-DC converters that will alleviate this issue.
- asolidtime1 4y ago
  You can still have a 12-volt bus, but since you're not plugging directly into the battery you'll suffer some conversion losses (buck converters are generally 80 to 95 percent efficient, depending on the operating conditions and cost)

amatecha 4y ago

Tip to OP (I think they already have this idea, based on the post): when that lead-acid battery dies, replace it with a LiFePo4, which is substantially more efficient, lasts 3x as long, has a higher energy density, provides a usable voltage far further into its discharging %, etc. etc... A couple pages that describe the differences linked below... tl;dr if you are starting a solar battery project, LiFePo4 is the clear choice by far, unless you're going for the absolute cheapest possible build due to immediate budget constraints. https://www.canbat.com/a-detailed-comparison-of-lead-acid-batteries-and-lithium-iron-batteries/ https://www.canbat.com/a-detailed-comparison-of-lead-acid-ba... https://www.power-sonic.com/blog/lithium-vs-lead-acid-batteries/ https://www.power-sonic.com/blog/lithium-vs-lead-acid-batter...

walrus01 4y ago
I don't disagree with you but lifepo4 have a high upfront one time purchase cost for something equivalent in capacity to a 12V 100Ah AGM, like easily $450-500 per unit or more. They do pay for themselves over time with their much greater longevity. Might be more than the blog owner wants to spend for what is just a fun hobby project. There are some 3U rackmount size nominal 48vdc 50Ah lifepo4 (approx 4.8kWh capacity) with built in bms and LVD you can get from china now.
- amatecha 4y ago
  Yeah, there's def the upfront cost, which not everyone can justify. Though, at the same time, a lower-amp-hour battery can provide as much actually-usable energy as a higher-amp-hour-rated SLA battery (so you could purchase a LiFePo4 battery with a lower amp-hour rating than the equivalent SLA battery but still get the same run time). I wouldn't know how much lower you can go though offhand.
- sgt 4y ago
  With lead acids you just have to make sure you don't go below 40% charge. They don't tend to like that. The deep cycle ones are a bit better but I've experienced them deteriorating quickly too once you go too low. The other disadvantage is that they are quite heavy and might end up taking up lots of space. I'm personally still using lead acid, but with plans to go LiFePo4.

deleted 4y ago

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YarickR2 4y ago

So; how much did the whole setup cost ?

nivenkos 4y ago
It says 2000 EUR at the bottom.

choeger 4y ago

Cool project. I think we really need some free software sensor/controller libraries/frameworks for solar setups. The reason is that here in Germany, and presumably elsewhere in Europe, these "balcony powerplants" are taking off. You are allowed to plug up to 600W (soon up to 800W) into your socket without further trouble. But unfortunately, most people will waste a lot of energy this way. Very few people will have permanent usage of 100W or more. Instead, consumers like refrigerators will turn on and off multiple times per hour. So the ideal setup would consist of one or more load-measuring sensors, a smallish long-lasting battery (LiFe?), some oversized panels (say up to 2kW) and a converter that hooks everything up. The controller should ensure that you feed power into your grid only when you need it and otherwise charge your battery. I think that such a setup could easily get you 4kWh/day of consumption in spring and summer. And potentially still 1kWh during most winter days.

tcfhgj 4y ago
It's not wasted energy. The country (perhaps even the continent) still benefits from it by having to burn less gas and coal
- _heimdall 4y ago
  With regards to the wasted energy that is potentially made by the panel but unused, that doesn't offset any other power production since the power wasn't going to be used anyway
  - tcfhgj 4y ago
    Of course the power is used. It's in the grid, and every power source has to be compensated by a power sink, otherwise you have instable grid = blackout if the deviation is too big
    - _heimdall 4y ago
      Are you assuming the panels are grid-tied? I may have missed that in the article, the setup sounded very off-grid to me at which point the power potential is lost if not used immediately.

ofisboy 4y ago

Hey peeps. Sorry for hijacking the topic. I also live in the Netherlands and my backyard perfecty faces south, which means i get huge sunlight on that side of the house. But because my house has a glass-roofed extension on the ground floor, all solar companies i spoke say they can’t install panels on the roof because they can’t build scaffold on that side. Here’s an image to explain a bit better. [image](https://imgur.com/a/WE1Qojf https://imgur.com/a/WE1Qojf) So the red area is the glass-roofed extension on the ground floor. And blue area is the space on the roof that solar panels should be placed. Green is a dormer (which they said they can’t also put panels on top) I was wondering any dutchies might know a solution/advice a company about this? Also is there any portable panels that i can put on top of the glass extension? Thanks

hellweaver666 4y ago
I replied about this on another comment but have a look at "We Do Solar" their product is designed for installing on balconies but I guess there is nothing to stop you installing it where ever you like! (You might just need to add a bit of a frame to support them?)
- jacquesm 4y ago
  Beware, those tend to be ballasted, for mounting on a light roofing structure you really want something that isn't ballasted.
bartislartfast 4y ago
not in NL but my parents have the same problem - glass roofed extension stops the installation I dont understand why they can't just access the roof from the other side, climb over the apex and down. They walk all around on the roof once they're up there, does it really matter which side they climb?
kippel 4y ago
It isn't clear from the picture and I guess it's too obvious, but if you have a neighbour, they can climb from their roof. That's how my neighbour got his installation done. I have seen them do more complicated installations (4 floors scaffolding + crane to lift panels), I don't know why they refuse that one.

winrid 4y ago

The other problem is the 3.5 watt draw, or 600ma at idle, of the PI4B. If you used a PI Zero with an ethernet expansion board this goes down to 100ma at idle. 6x less. You still get 1ghz cpu and 512mb of ram. I could even run django and postgres on that. Certainly you don't need gigabytes of ram to run the blog. :)

bullen 4y ago
The Raspberry 2 (original ARMv7 not underclocked Raspberry 3 ARMv8) is the best low power server. 1W idle and 2W 100% (6x more perf. than Raspberry 1 = Zero with Eth.). They saturate the SD card SPI almost to the byte/second. 32-bit is enough forever, specially when you only have 1GB, but I'm staying on 32-bit on my 8GB RPi 4 too, because 4GB per process is enough when you also need the OS to have ample RAM. If you are lucky enough to have some ARMv7 RPi 2 and/or Rpi 4 8GB, they will be priceless for eternity.
- olabyne 4y ago
  The RPi 2 is the unpopular kid of the familly, I don't know why. Maybe it got erased pretty quickly by the Pi3 performances and Wifi capabilities. The thing I don't understand tho, is why they didn't chose this Soc for the Pi Zero original, instead of using the already decade-old ArmV6 CPU.
  - bullen 4y ago
    They can't, the RAM was external which wouldn't fit on the one sided Zero. Thus why they bounded the 512MB ram in the package for Zero 2. Physical limits are now everything you'll see until the end of time. 8GB is the largest RAM you will ever get in one chip. 1TB is the largest Micro SD. Etc.
- roeles 4y ago
  A Pi Zero can go down to 0.5W idle. The Pi Zero 2W should also be good, but is very hard to obtain right now.

shreddit 4y ago

Can someone recommend a brand of solar panels or a retailer, preferably in europe?

mgraupner 4y ago
It does not really matter, they are basically all the same. Only thing to watch out is that they should be build with half-cell technology and monocrystalline (which almost all of them are, technology does not differ that much in solar panels). 400 W Panels are pretty much standard.
bartislartfast 4y ago
I think most countries in Europe would have local solar panel sellers. I'm in Ireland which is usually pretty bad for availability of things, (for example, there's no amazon.ie - we have to buy from UK or DE) and even here we have solartricity.ie, solarstore.ie and several others. Longi panels are what I got, if you want a recognisable brand name Panasonic also do them.

archi42 4y ago

For those thinking about replicating this: Victron is really popular because it's extendable and the management interface is reasonably open, but the zoo of required devices makes the costs explode quickly. Maybe look at Deye instead. I'm running a 12kW unit (they're available smaller) with a 48V battery. The software is in poorly translated to English, firmware updates are made by the manufacturer remote on request and it has no shadow management (meaning it might end up on a local maximum in the MPPT, not the global maximum) - but the unit cost me about 3000€ with 10yr warranty instead of the >7000€ for an equivalent zoo of Victron parts. Of course it can do black starts from PV or battery, and act as a UPS on a secondary output. Pulling data locally can be done using a RS485 modbus interface; so I open my firewall only for firmware updates. The 3.6kW single phase unit (SG05LP1) can be had for less than 1300€. A 5kW three phase unit is only a little bit more expensive, but I'd worry about standby consumption in low power scenarios with only a few modules (mine hogs 80W, but a three phase Victron setup does so as well). These are string inverters, so you need more modules for them to reach their start up voltage, and then some more to put them into the MPPT zone. The 1 phase starts at 125V and the MPPT tracker works with 150-425V, the 3 phase units 160V & 200-650V respectively. When I browsed the market there were other offerings from other brands with 90V start up; but be careful to get a unit that's legal to connect to the grid IF you want to have grid fall back (here in Germany, Victron and Deye are legal - at least the parts I looked at. But you will always need a electrician with a concession to register them with the grid company. Some people don't care and just setup their systems though). Important: The voltages depend on the chosen PV module; mine are in the 40V per module ballpark, but iirc I might maybe have seen up to 60V? So for the 3.6kW unit you'd want at least 3 or 4 modules.

madaxe_again 4y ago
Not sure what zoo of parts you’re referring to? I have two multiplus 5kva 48v, a bmv-712, a venus gx, and a pair of their biggest MPPTs - and for our pretty large install it shook out at about €4,500. Without the redundancy, it would have been more like €2,500.
- archi42 4y ago
  Don't get me wrong, the Victron systems are nice & I envy their great traits I've praised in sibling comments. But your system doesn't compare on the power specs. There is no exact equivalent for the Deye with Victron. The Deye can do 15.6kWp solar, split over 2 MPPT. The topology is such that one MPPT can do 15kW while the other does 0W (I did not believe this, but I've talked to the manufacturer and it's indeed correct). The inverter can output 12kW AC, or draw that much for charging the battery. If your load is not balanced well, there is a video of someone testing it with 12kW sustained output on a single phase (this is only useful for a select few maniacs though; I'm not one of these). And if the 12kW is not enough, you can put them in parallel (like with Victron). I deleted my notes on the Victron setup, but this is something similar to what I was looking at (about Sept 2022): 3x Multiplus 48/5000 on the AC/DC end for full three phase setup (back then 1700€ each, now 1300€) - mind those can really "only" push 5000VA or 4000W at 25degC. Our roof would be 1x MPPT RS 450/200 (pretty stable at 1800€), the string in the garden 1x 450/100 (1200€ in Sept, 1000€ now). A RPi plus USB adapters and PSU and sturdy case for VenusOS (or a GX unit) would be close to 100€ extra, also add additional cables and the necessary busbars (dunno, 200€?). For a three phase that's 7000€ today, or 8400€ in September. Of course that's just one way of building a system, and Victron is amazingly flexible - and with my 14kWh battery two multiplus would probably have been enough (caveat emptor: no idea if my grid operator would have accepted 2x5kVA or rejected it due to the inbalance). Lots of people use a SmartShunt or Lynx, these also add to the costs of a Victron system. Why zoo: The footprint of the Victron 3x MP and 2x MPPTs is nearly 0.9m²; add busbars and other periphals, and you're easily at 1m². Plus, each device needs some clearance due to the heat. The Deye is one unit with 0.3m² footprint. This is also nice.

wkjagt 4y ago

Being in the Netherlands makes this very challenging indeed. I am from the Netherlands but don't live there anymore. I came to visit family in December a couple of years ago instead of the usual summer trip and I had forgotten how incredibly gloomy it gets. Short days, dark, low hanging clouds much of the time. Not much solar energy on those days.

jacquesm 4y ago
Indeed, December here we made all of 85 KWh, whereas the peak day in April so far produced 68 KWh and I fully expect summer days to be much better than that still. So that's a ratio of 1:30 between winter and summer! The worst day in April so far was 13 KWh, the worst day in December was 0.3 KWh. So no matter what you do, you'll end up using power from the grid. And no realistic battery system is going to give you three months worth of storage. At best you'll have two days worth, maybe three.

jb1991 4y ago

> my balcony is facing east. This means it only receives direct sunlight from 16:00 onward during spring and summer. I’m confused. The sun rises in the east. By late afternoon it would not be directly shining on an east-facing balcony, would it? The most sun would be in the morning on that east side, I would think.

deleted 4y ago
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louwrentius 4y ago
I'm mixing east and west, sorry, I'm going to update my article.

hankman86 4y ago

Did you ever work out how much energy was expended to manufacture and transport the parts? Chances are that with solar panels facing west in a place like The Netherlands, it will take a long time to come out on top with your carbon footprint. I reckon that the most energy-efficient setup for your blog would be a hosted solution. Data centres are already optimised for low energy use. And some cloud providers have committed to become carbon neutral. Lowering your overall household electricity use would be a more effective way to lower your carbon output.

mgraupner 4y ago
I also think that this setup will not be worth it ecologically or economically.
trabant00 4y ago
And I bet his hardware saturation is low too, making it an even worse use of resources compared to shared hosting in a data center that uses bin packing or live migrating VMs or whatever. Because in the end you care about resources used for the actual work done, not the work capacity of the hardware. While it doesn't make much difference at this scale and it is a valid experiment to learn about solar power, it is telling of the general view about energy and environmental impact. People equate solar or wind or electric vehicles with green when the devil is always in the details.
bartislartfast 4y ago
Did you read the article? Quote: > It's fair to say that my experiment isn't rational because of the sub-optimal solar conditions. Yet, I'm unreasonably obsessed by solar power and I wanted to make it work, even if it didn't make sense from an economic or environmental perspective2. This is just a fun experiment

wanabananascene 4y ago

[flagged]

jve 4y ago

I am less of a DIYer than the author and safety was always a priority... good author knows about amps, cable sizes, etc. But charging lead acid battery inside a house? I've stumbled across warnings where it says they must be charged in a well ventilated area. Anyone care to chime in, for the safety of author? https://www.ccohs.ca/oshanswers/safety_haz/battery-charging.html#:~:text=When%20leac%2Dacid%20batteries%20are,number%20of%20batteries%20being%20charged https://www.ccohs.ca/oshanswers/safety_haz/battery-charging.....

drzaiusx11 4y ago
Sealed lead acid (SLA) batteries only outgas an appreciable amount when overcharged/overdischared. Vented instead of sealed types can also be used indoors but require their own ventilation system. The majority of UPS systems use SLA batteries indoors.
- jmnicolas 4y ago
  But is it safe to inhale the gases?
  - chucksta 4y ago
    Its Hydrogen, the concern is explosion https://www.ccohs.ca/oshanswers/safety_haz/battery-charging.html https://www.ccohs.ca/oshanswers/safety_haz/battery-charging....
    - moffkalast 4y ago
      > Overcharging a lead acid battery can also lead to the generation of hydrogen sulfide, which can cause harm to workers if exposed. The concern is also the toxicity of H2S. Most SLA chargers are poorly designed and will overcharge any battery that isn't in mint condition.
      - drzaiusx11 4y ago
        Agreed that cheap "trickle" chargers with unregulated voltage can cause overcharging if left on for too long (days to weeks on larger batteries, as their current is usually under 1A) Better to invest in a "float" charger with a regulated output and automatic shutoff. As with many subjects, if you go the cheapest route you pay with time or safety risk.

Havoc 4y ago

>Suddenly you realise that making the background on all monitors black saves ~20 Watt. Depends on panel type - some are lower @ white

itsyaboi 4y ago
Curious, do you have any examples of monitors like that? Less light and lower brightness reducing power consumption is intuitive, the inverse less so.
- Havoc 4y ago
  Some LCD screens. It's pretty marginal though https://www.quora.com/Does-a-white-background-use-more-energy-on-an-LCD-than-if-it-was-set-to-black https://www.quora.com/Does-a-white-background-use-more-energ...

mugiseyebrows 4y ago

If you only serve static files you can use Arduino (or better) MCU (it has lan shield) and decrease power consumption three times, and 18650 instead of car battery can perform better.

vrglvrglvrgl 4y ago

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prmoustache 4y ago

Wouldn't a small wind turbine make more sense in the Netherlands?

nextlevelwizard 4y ago
On a random balcony in a city? I don't know how efficient turbines are, but that doesn't sound very promising.
joshuanapoli 4y ago
I think that wind turbines are harder for DIY because they need to be mounted well above the roof height to get non-turbulent airflow.
detaro 4y ago
really small wind turbines are almost never worth it
jacquesm 4y ago
No, it wouldn't. The capacity factor for a small, unidirectional turbine in non-laminar flow is going to be somewhere between 0 and 15% depending on how lucky you are with the prevailing wind direction. Small turbines also tend to be quite noisy. There was a small unit that was sold by a Canadian solar/wind installer that was named the 'Whisper', but we privately called it the screamer (and it was one of the main reasons we ended up building our own turbine, all of the ones that were on the market were small, loud and inefficient because they were all fixed pitch).
- dredmorbius 4y ago
  There's also the problems of mounting on a structure, let alone on an apartment building with limited exterior access (as with this case). Turbines vibrate, and over time can cause joints to weaken as nails are loosened. That's even without considering the disruption to laminar flow (e.g., full wind efficiency) caused by diverting wind-flow over a structure. Upshot is that if you do want a wind turbine and have a viable use-case, you'll still want a free-standing tower well clear of structures, trees, etc.

Proven 4y ago

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cr3ative 4y ago

I'm a little confused about the need for the inverter here. The SmartSolar can provide output the Pi can use. Why not just throw a 12v-compatible USB power supply on there? Going up to mains then back down to 5v seems inefficient. Am I missing something? edit: I'm wrong! My SmartSolar has "LOAD" output but OP's does not. Ref: https://www.victronenergy.com/solar-charge-controllers/smartsolar-mppt-75-10-75-15-100-15-100-20 https://www.victronenergy.com/solar-charge-controllers/smart...

roeles 4y ago
Still, there's the UUGEAR Zero2Go board that you might use to step down from 12v to 5V: https://www.uugear.com/product/zero2go-omini-wide-input-range-multi-channel-power-supply-for-raspberry-pi/ https://www.uugear.com/product/zero2go-omini-wide-input-rang...
- asolidtime1 4y ago
  IMO, these types of listings (power supply for <insert popular development board>) prey on people who don't have a ton of EE knowledge. A pack of 10 2A buck-converter modules from Aliexpress will run you about $5
pflanze 4y ago
Why do you think the Pi is powered via the inverter? I can't see mention of this, and the picture of their setup shows the Pi being powered by a step-down from 12 V.
- GoToRO 4y ago
  That picture is not his setup.
  - pflanze 4y ago
    I'm talking about the picture with the caption "the latest iteration of my solar setup". Maybe you tripped over the text "So I decided to build a new setup inspired by Will Prowse solar demo setups, which is pictured below:", which I understand as "So I decided to build a new setup, pictured below, which was inspired by Will Prowse solar demo setups:".

dom96 4y ago

I often wonder if wind power could be harnessed in a similar manner on a balcony. Anybody try this to power their blog or saw someone else do something similar? or is this simply unfeasible?

_heimdall 4y ago
Wind is tricky depending on where you live. In the US there are surprisingly few places where smaller consumer-grade windmills make sense. Its been a while so this may be off, but I want to say you need a consistent wind of something like 10-15mph for most turbines to be of any real use Even then, a 3000W turbine is usually best on something like a 30-50' tall pole In certain areas wind can be efficient, in most areas (at least in the US) solar is much easier to deal with and more reliable

pflanze 4y ago

I see a safety hazard with the exposed battery terminals (as shown in the picture "A 12 Volt 230 Ah lead-acid battery"). AFAIK, lead-acid batteries are less powerful than Li-ion/LFP but would probably still start a fire or give nasty sparks if something metallic falls onto the battery. (I'd be happy to be corrected.) > The drawback of a 12-volt system is the relatively large currents required to charge the battery and power the inverter. This requires thicker, more expensive cabling to prevent energy losses in the cabling. Arguably it's only for the discharging via the inverter that you need the thick cables, as otherwise they don't need to be thicker than the cables from the panels. (The current for charging could be much lower than the maximum discharge current.) -- Except if the MPPT steps down the voltage from the panels to the battery by a lot.

louwrentius 4y ago
See the footnotes.

foodoos 4y ago

[flagged]

GoToRO 4y ago

Ditch the inverter and you are set.

asolidtime1 4y ago
Please read the article or at least look at the image of their setup; they only switch on the inverter occasionally to power their main computer and monitors

foodoos 4y ago

[flagged]

xony 4y ago

[dead]

turtlebits 4y ago

You don't need an inverter if you're just using an rpi. You can get away with a cheap 12v car USB adapter. I do this for my off-grid wifi (rpi and 5g phone plugged into USB).

ccorcos 4y ago

It’s always frustrating to me to see an inverter in these setups. All of your digital devices actually run on DC current! Your computer, monitor, phone charger… Inverters consume energy just being on, whether current is being drawn or not. And they’re expensive! Without the inverter, a solar panel+battery setup is super simple and I’m curious to see a movement towards low-voltage circuits in homes. You can easily power all of the lights in your home with a solar panel connected to a 12v battery. Double in size and you can power your TV and router as well. This isn’t going to save you a significant amount of money though. It’s just interesting. Big ticket items like your water heater or air conditioner consume a lot more power and will probably need an inverter, etc.

louwrentius 4y ago
The key issue is that all my existing equipment is 230v. I would have to rebuy everything. If you need an inverter anyway for hvac, you have added complexity and no gains. Although not mentioned, I’m using 230v ikea fixtures with 12v led e27 bulbs wired to 12 volt, as you mentioned. Is indeed quite efficient, no inverter running.
- ccorcos 4y ago
  Yeah, but the annoying thing (from an engineering elegance perspective) is that most of those appliances that are on 230VAC convert to 12-48VDC internally (e.g. TV/monitor, LEDs).
  - louwrentius 4y ago
    Yeah regarding those appliances 100% I see the inelegant solution. Imagine all new equipment below x watt would be required to have a 12v input in addition to 120/230
kamranjon 4y ago
I always thought it would be cool wire parts of your home using PoE (power over ethernet) if you had some solar panels and a battery bank.

muyuu 4y ago

I may be out of the loop with prices but 2000€ sounds like a lot for such a small setup. Maybe the tradeoffs of going smaller are worse than I thought, but for ~3500€ I got what I roughly estimate to be worth about 3x as much in generation and storage.

1123581321 4y ago
I think that tracks. He seems to have spent several hundred on the panel, frame, wiring to his board and a right-sized battery. You would have incurred those per-watt expenses two more times. Most of the other costs to invert, switch source, and store power are fixed. He seems on track to build out his system even further, based on the intro, too, so he’ll probably catch up with you.
louwrentius 4y ago
The frames cost is 25%, which you wouldn’t have. Larger setups are often more efficient in price and performance. Going small is indeed expensive.

foodoos 4y ago

Magnets can generate energy.