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It's wild how overpriced Tesla Powerwalls are. 16 kWh battery with all of the UL supported listings etc = $3300 [0] 13.5 kWh Tesla Powerwall is $12k~$15k You

• toomuchtodo 9mo ago
  They have a 30% gross margin, they're just soaking up the federal US tax credit (which is also 30% for battery storage and extends through 2032). Alternatives: https://electrek.co/2025/12/28/opinion-its-time-to-start-recommending-some-tesla-powerwall-alternatives/ https://electrek.co/2025/12/28/opinion-its-time-to-start-rec...
  • latchkey 9mo ago
    A few of the alternatives have been reviewed by Will Prowse as well. His YT is a treasure of information. https://www.youtube.com/@WillProwse https://www.youtube.com/@WillProwse
• dns_snek 9mo ago
  You're comparing the cost of a battery with a full system. That 16 kWh battery requires a ~$3000 inverter to go along with it.
  • scarecrowbob 9mo ago
    Well, the math still maths, right? I am writing this off grid, using about 15kwh of batteries and a $1200 (6kw) inverter. My entire system puls panels and racking those panels, plus wiring some un-powered shacks was about $10k, though I did the work myself (which would probably hae been another 3-5k if I could have found someone to do it.
    • thechao 9mo ago
      > which would probably hae been another 3-5k if I could have found someone to do it. Yo. If you can find an electrician to stop by my house and turn a light switch off for less than 1000$, please inform me. I got a quote for 25k$ to install a system that size, and that price. City code has me by the balls: I can't modify my main panel without inspection, the inspector won't show up without a licensed electrician, and electrician wants the labor. I pointed out that we're talking 8 hours of labor — call it 2500$, lawyer money — and he was like "what's your choice". I'm in Texas.
      • ozim 9mo ago
        For 2500$ maybe you can pass the exam to become licensed yourself. Like do it over the weekends.
        • lostapathy 9mo ago
          This right here - I have been investigating getting my own contractor license for DIY work on a property I own that must be permitted but city will only issue permits to licensed contractors. Took a practice test for the exam on a whim and nearly passed it without studying. Anybody seriously considering DIY'ing the install of something like this probably could get a license without a lot of work.
        • adrianmonk 9mo ago
          To get a journeyman electrician license in Texas, you need to have 8000 hours of documented on-the-job experience working under a licensed electrician[1]. So you'd need to find an electrician who will let for you work them on the weekends, and if you work 8 hours every Saturday and every Sunday, then it will take you 500 weekends. A residential wireman license only requires 4000 hours[2], but I'm not sure if that kind of license would be good enough for the inspection. --- [1] https://www.tdlr.texas.gov/electricians/apply/individuals/journeyman-electrician.htm https://www.tdlr.texas.gov/electricians/apply/individuals/jo... [2] https://www.tdlr.texas.gov/electricians/apply/individuals/wireman.htm https://www.tdlr.texas.gov/electricians/apply/individuals/wi...
        • 9mo ago
  • mbesto 9mo ago
    That's fair. Better comparison: Author's config: 3x Powerwalls + inverters = 40 kWh 4.2 kW array £39,360 = $53k USD Alternative: EG4 18kPV Hybrid Inverter = $5000 3x RIUXU = $9600 10x Trina Solar 435w panels = $1580 Cabling, installations, etc. = $5000 Total = $21k It's not even close...
    • pchew 9mo ago
      This is still not an accurate comparison. I'm not a Tesla fanboy but of all of the major players in the non-diy game (Enphase, Franklin, Tesla, Sol-Ark) they provide the best value for money, and are impressive pieces of equipment. The EG4 18k has 11.5 kw backfeed capability, with a rather pathetic 65ish amp in-rush. Obviously 18kw usable solar capacity(they technically let you land up to 21kw, but only 18 is usable). The Powerwall system you outlined can take 60kw of usable solar input, has 34kw standing backfeed capability, and a whopping 555 amp in-rush (not a typo, it's 185 amps per unit). Not to get in to warranties, etc.
      • mbesto 9mo ago
        None of those things matter when your solar array is 4.5 kW and you have a standard 150A/200A grid in.... Like I said, they basically are not sold to scale like a normal household uses electricity. EDIT: What the heck is in-rush and backfeed? Are you talking about AC input to charge the batteries? The 18k is 50A @ 240VAC (12kW) fyi. Also, why does the charge rate even matter there? For the AC output its also 12 kW...the family is average 48 kWh days, which is 2 kW hourly average...
        • labcomputer 9mo ago
          Inrush is surge capacity. Starting a big motor like an air conditioner can require 2x or 3x the continuous running amps, but only for a few seconds.
        • pchew 9mo ago
          Inrush is exactly what it says it is, it's inrush current. When you have a sudden surge on something, that's inrush. Lots of appliances in your home have a large inrush, much larger than the breaker they're on. Inrush happens faster than a breaker trips, which doesn't matter when you're on the grid and the inrush is lower than your mainbreaker, it matters when you have an inverter in the way with a passthrough limit and an inrush limit. Typical central HVAC units have LRA over 100 amps. If we're talking about 'doesn't even matter with a 4kw array' well, hell, how the hell you gonna charge ~40kwh of battery with solar array that nominally produces 20kwh a day on its best day, assuming all conditions are perfect? Backfeed is what the inverter can push out from the battery to the home. It's the size of the tube coming from the gallons of water reservoir. EG4 18k has a tiny tube, no matter how much battery you put on it. Like emptying a 50 gallon drum with a drinking straw(and with the 4kw array, filling it with a 12 oz cup).
• ortusdux 9mo ago
  IIRC, the original idea was that they would pull older batteries from circulation when their capacities dipped, and then repurpose them as powerwalls, an application where weight is irrelevant. This was back when they expected the batteries to plateau at ~80% capacity after a few years, and they had battery swapping on the roadmap, so they needed to plan for a future where they had a steady supply of batteries that car customers did not want. The idea took hold, but the batteries lasted longer and swapping didn't pan out, so now they are competing with themselves for battery supply.
  • benoliver999 9mo ago
    Electric car battery degradation has been super interesting, in that they are going way further than people thought they might. Jonny Smith on youtube bought a 300k+ mile Tesla and the battery is at like 75% health. As far as I can tell if your battery isn't air cooled, it can go a very long way
    • magicalhippo 9mo ago
      There was some research[1] that strongly suggested that varied use makes them last much longer than the steady use that most battery tests do. That is, bursts of high-current draw followed by moderate draw etc vs the constant current load typically used when evaluating battery performance. From the paper: Specifically, for the same average current and voltage window, varying the dynamic discharge profile led to an increase of up to 38% in equivalent full cycles at end of life. This was unexpected, hence explains why they fared better than predicted. [1]: https://www.nature.com/articles/s41560-024-01675-8 https://www.nature.com/articles/s41560-024-01675-8 Dynamic cycling enhances battery lifetime (open access)
      • LordDragonfang 9mo ago
        Huh, unexpected is right. Bursts of heavy usage being better for longevity than steady usage goes against pretty much all conventional engineering wisdom.
• O5vYtytb 9mo ago
  That's not really apples-to-apples comparison. The Tesla batteries are AC coupled so they work with an (AC coupled) microinverter array. For a DC coupled battery you have to have a hybrid inverter and DC couple the batteries. Your point that they are overpriced still stands though.
  • mbesto 9mo ago
    Ya as someone else pointed out, powerwalls essentially have an inverter built in. But this is really dumb to have inverters tied directly to each powerwall battery. This is like anti-scale.
• HexPhantom 9mo ago
  I think "overpriced" depends a lot on what problem you're trying to solve
  • mbesto 9mo ago
    Powerwalls don't uniquely solve any problems other brands can't do.
  • IAmBroom 9mo ago
    A statement so vague as to be tautologically true.
• jillesvangurp 9mo ago
  There's going to be a bloodbath in that market in the next years. There are a lot of battery producers and most of them are not producing at full capacity. At the same time, manufacturing cost is dropping as well. Some battery makers are producing batteries at a cost level of around 60$ per kwh. At that cost, the 16kwh battery would come out below 1000$ (not the same obviously as the product price). Sodium ion might push those prices even lower. Below 50$ soonish and eventually closer to the 10-20$ range in maybe 5-10 years. At that point we're talking a few hundred dollars for a decent size domestic battery. You still need packaging, inverters, etc. of course. But the ROI at anything close to those price levels is going to be pretty rapid. And it wouldn't break the bank for households across the world. Add a few kw of solar on roofs, balconies, etc. It won't solve everyone's problems and certainly not in every season. But it can help reduce energy bills in a meaningful enough way. Even in winter. Also worth pointing out: most of the US is south of Cornwall. The Canadian border runs roughly at 49 degrees latitude. Cornwall is the most southern point in the UK sits at 50 degrees. If it can work there, most of the US has no excuse. Also, the UK isn't exactly well known for their clear blue skies. Even people in Scotland much further north manage to get positive ROIs out of their solar setups.
  • itsamario 9mo ago
    Companies like Schneider electric have systems for 25-50% the hyped brands but they don't provide batteries. This is the company that owns APC so its not like theyre new or untested. They just don't bother with brand awareness
    • nagisa 9mo ago
      Its weird to read about Schneider Electric not bothering with brand awareness. They aren't a household brand, sure, but they are well up there with Siemens and the like in industrial/b2b sector and their marketing budget is allocated accordingly.
      • MisterTea 9mo ago
        All they did was buy up everyone's else brand and put their brand over it. Modicon PLC's, Magnecraft relays, etc.
• nop_slide 9mo ago
  You might find https://www.basepowercompany.com/ https://www.basepowercompany.com/ interesting, 25kwh battery for $700 down and $20/month
• modeless 9mo ago
  The crazy thing is you can buy a 69 kWh battery from Tesla for $36,990, and it comes with a whole car too.
  • vagab0nd 9mo ago
    Exactly! This is how the future should be: solar panels + portable huge battery arrays doubled as vehicles + grid as backup.
• microdrum 9mo ago
  For what it's worth, Tesla PV/batt inverters are bad, almost as bad as the Chinese manufacturers mentioned ITT. PW3 has very high failure rate ~10%+RMA, not good enough IMO to be in the path of power at my house. (Their motor inverters are world-class, but totally different topology)
• torginus 9mo ago
  A small thing I want to remark is that at that price, a Model 3 costs less than 3x, and has more than 3x the battery capacity. Considering DC connectors on EVs provide a direct electrical connection to the battery terminal, and the charge-discharge circuitry in residential hybrid solar inverters can handle them just fine (provided it supports the voltage ranges, but people did this). I think it's an enormous missed opportunity, that the most common charger standards don't support this (CCS2 doesn't, Chademo does, no idea about NACS) If this was a thing, I think it would completely reshuffle the EV market, I don't know how used residential batteries depreciate, but I doubt they lose more than half of their value in 5 years like EVS do.
  • wang_li 9mo ago
    The Ioniq has the ability to provide battery power out so you can plug your house in.
    • torginus 9mo ago
      I'm talking about something a bit different - the Ioniq uses a V2L, which means it has an onboard inverter that generates AC mains voltage through the plug, and can be used to provide equipment directly. What I'm describing is using the cars DC charge port and connecting it to inverters DC battery port.
• tzs 9mo ago
  It is interesting to compare to V2H systems. I believe Chevy offers V2H on all 2026 Equinox EVs. Enabling this needs their V2H Enablement Kit and I believe you also need their PowerShift Charger. That would be around $38k for a 2026 Equinox EV LT, which has an 85 kWh battery, $6300 for the V2H Enablement Kit, $2000 for the PowerShift Charger. Installation via the company Chevy says to use is $2000-5000 according to the net. That brings us to $51-52k, and would give 70ish kWh of usable backup capacity. That's around $750/kWh of capacity. Getting that capacity with Powerwalls would require 5 of them and cost quite a bit more. Plus, with the V2H approach when you aren't having a power outage you can use it as a car. :-)
• chris222 9mo ago
  Yah, check this one out. https://www.docanpower.com/panda-52v-942ah-48kwh-prebuilt-pack-1 https://www.docanpower.com/panda-52v-942ah-48kwh-prebuilt-pa...
  • mbesto 9mo ago
    I actually own three of 15 kWh versions :) They are cheap and they work but they're not UL listed...so they dont go anywhere near my home.
• KaiserPro 9mo ago
  Now they are overpriced but up until 2022/3 they were the best value unit.
• homebessguy 9mo ago
  In the UK, where the OP is from, the equivalent of the battery you linked is available from Fogstar for £1850 (includes 20% VAT), shipped. Without the VAT that works out at ~$2000. A compatible high end 9kW inverter is available for around £1200. The ROI is really attractive once you look past the overpriced kit.