Buy Your Friends Batteries

(domenkozar.com)

97 points | by domenkozar 2 hours ago

29 comments

  • Retr0id 1 hour ago
    > Create a battery birthday club. Buy each friend a battery on their birthday until everyone has one.

    At that point, wouldn't it be easier if everyone just bought their own? And then whoever has the latest birthday doesn't have to wait a year to get theirs.

    • cbarnes99 1 hour ago
      I think the point is that breaking it up makes the cost more palatable. It's also easier to convince people to spend a bit of money for people they care about than a bunch for themselves that they don't strictly need. People also often struggle to think of gift ideas for birthdays.
      • deepfriedbits 1 hour ago
        True, but you're still buying an entire battery yourself in the course of a calendar year.

        I love the spirit behind this but it's strange advice. I consider myself lucky to have a healthy roster of adult friends, and I still think getting 16 of them to spend significant money on each other's birthday would be a big ask to pull off.

        • underdeserver 45 minutes ago
          The first friend gets to share their experience with the group, that can then decide to keep buying for other members or not.
      • carabiner 46 minutes ago
        Best gifts are sub $5 and from a thrift store, like a funny shirt or mug.
    • oytis 1 hour ago
      But then you still have to buy birthday presents on top of that
      • Retr0id 1 hour ago
        If everyone's giving everyone the same gift, it's not really a "gift" any more, more of a p2p buy-now-pay-later arrangement (which isn't a terrible idea, but it's suboptimal for those with later bithdays).
        • chalupa-supreme 26 minutes ago
          Yeah this pretty much just a “tanda” except everyone pitches in to get the battery instead of paying out to the birthday person.

          https://en.wikipedia.org/wiki/Tanda_(informal_loan_club)

        • blitzar 1 hour ago
          Might as well just have an annual theme and try to negotiate a bulk discount.
        • ruined 1 hour ago
          it's simple. if i were part of an economy, we would all just act rationally. that way everything would be efficient
        • cactusplant7374 1 hour ago
          Not everything needs to be optimized. Probably only rich people would engage in such a scheme anyway.
          • Retr0id 1 hour ago
            The whole premise here is cost optimization.
    • domenkozar 1 hour ago
      That's step one, next is your friends.
    • lowbloodsugar 50 minutes ago
      It's just fantastically naive on so many levels.
    • benj111 1 hour ago
      No. This is how building societies work.

      You may not have £100,000 but if you get 1000 people with £100 then you can buy a house.

      Obviously the birthday system doesnt address the interest, but I'm sure your friends would be ok paying interest right?

      • rcktmrtn 56 minutes ago
        Yes, but I think the missing ingredient is that building societies "bid" to decide who gets to go first. Whoever is willing to take the smallest loan/pay back fastest gets preference.

        Reinventing building societies seems very cool to me -- it's a little more nuanced than the birthday thing, but it's a system that can work with assets that generate value.

      • iwontberude 1 hour ago
        [dead]
    • toomuchtodo 1 hour ago
      It is like an energy storage cost cutting rotating potluck. blitzar mentions bulk buying in a comment, which is a great idea to drive down cost. Not sure what the EU version of that looks like, the US versions are:

      https://solarunitedneighbors.org/

      https://www.brightsaver.org/

      Europe has quote a bit of renewable generation currently that is curtailing or otherwise going unused, and needs all of the battery energy storage it can get (residential, commercial, utility scale) to convert curtailment into realized clean energy offsetting potential fossil energy usage (gas and coal).

      Solar Power Is So Big in Europe That Electricity Is Being Wasted - https://www.bloomberg.com/news/articles/2026-05-13/europe-so... | https://archive.today/nAdiA - May 12th, 2026

      > Hundreds of millions of solar panels have been installed in Europe, turning solar into the region's biggest source of power during summer months, but the system around it hasn't kept up. A record amount of electricity is being wasted because grids can't handle the surge in output, with about 40 terawatt-hours of electricity expected to go to waste in the coming months. The glut of solar power is pushing power prices deep below zero during peak solar hours, eroding returns for producers and forcing them to shut down plants, with consumers potentially paying twice for the subsidies and compensation.

    • iwontberude 1 hour ago
      [dead]
  • isoprophlex 1 hour ago
    > You are also safer during a power outage. The STREAM 5000 provides up to 3 kW of off-grid output. Keep essential devices on its backup output and reserve some battery capacity, and your refrigerator, lights, router, and laptop can keep running when the grid goes down. An ordinary grid connection does not back up the whole house automatically; the backup output must be configured correctly.

    Being able to cut over your entire house from grid power to a battery requires an invasive, expensive change to most connections. I wish people would stop breathlessly promoting batteries (which are good! we need decentralized storage!) because "you can use them to run your fridge, router, etc". Yes you can, but for almost all consumers it's an order of magnitude more effort and cash compared to just buying and plugging in a battery.

    • ssl-3 1 hour ago
      And the proposed battery solution only works at up to 3kW. My electric range uses more than that, and my water heater, clothes dryer, and aircon each come close.

      And, sure: I can get by very well with refrigeration, networking, computing and/or TV, and lights during a power outage. But those loads need to be segregated, or it just doesn't work. That adds more expense.

      And since those segregated loads don't even come anywhere near 3kW, it isn't clear to me how I'm to be maximizing my local use of surplus power events.

      There are grid-interactive battery solutions from companies like EG4 that can go betwixt the entire house and its grid connection, but this isn't it.

      • croemer 45 minutes ago
        Why do you need to segregate them? Can't you switch the rest off? Or is the problem that otherwise you'd supply neighbors as well?
        • ssl-3 16 minutes ago
          Just because it's the real world. :)

          If things aren't segregated and the power goes off while I'm cooking, the aircon is running, the water heater is doing its thing, or whatever, then: I exceed 3kW.

          3kW is the maximum that the device can supply. If load exceeds maximum, then something will (must) fail.

          Hopefully it fails gracefully, but I mean: I've been married before and I understand how terrific and fantastic it can be when things go slightly wrong at home when I'm not around to address them. The less Rube Goldberg my creations are, the more peaceful my life is.

          (None of this modern name-brand grid-tied stuff is any particular danger to linemen. It won't output anything on those terminals if it doesn't have an AC waveform to synchronize with.)

    • Aachen 1 hour ago
      Not necessarily the point. If it provides a normal wall outlet I'm happy to plug essentials around for the one time per 1-2 decades this happens for longer than 4 hours and the fridge/freezer/laptop needs a boost
      • smcameron 3 minutes ago
        Must be nice. I live in Virginia, outside Richmond. For the past 8 years, the power company has failed to provide me with even 3 nines of power availability (that means at least 9 hours of outage every year for the past 8 years. Just had a 17 hour outage as of last night, lost everything in my fridge. Again.)
      • EvanAnderson 1 hour ago
        As long as you're not opening the fridge / freezer during the outage (and you have sufficient thermal mass of food in it) you don't need to worry about "boosting" it during a power outage of only 4 hours. I don't recall the rule of thumb off the top of my head, but for at least 6 hours I'd expect the contents of normal fridge / freezer to be just fine (as long as there's thermal mass there).
        • jonathanlydall 1 hour ago
          Can confirm from years of load shedding in the past in South Africa where my area had 4 hour outages.

          That duration was tough for various reasons, but fridge and freezer were not really an issue.

          I was very happy when they changed to 2 hour outages (albeit twice as many), and then even happier with not having load shedding for about 2 years now.

        • Aachen 28 minutes ago
          Yes, thanks, indeed I'd start doing this *after* 4h if I have such a battery since fridge, freezer, and laptop are all in different places and they'll run for 90 minutes to cool or charge and it's probably not bad to get around to all towards the end of the first day with no stress. It was just an arbitrary starting point really. Freezer contents are also all fine after 24h but maybe some edges got towards the thawing point. I've not tried it out and simply wouldn't care to find out
        • DontchaKnowit 32 minutes ago
          They said longer than 4 hours
      • rtkwe 1 hour ago
        The issue there is the plug would be on the battery which you're unlikely to have mounted in a convenient location for things like your main fridge, router, and computer. For me all 3 of those are pretty far away from the most likely places I'd put a battery bank. I have a mobile one I keep charged up for emergencies and long power outages and have a small portable solar panel for it for multiday outages.
        • Aachen 25 minutes ago
          Ah, right I was picturing an oversized car battery that you can lug around. Extension cord then? Not sure but this seems surmountable without having to rewire the house and get a permit or licensed unit for feeding the grid
      • coldpie 1 hour ago
        I dunno. TBH I'd rather just let the food go bad than bother with the expense and hassle of having a battery and keeping it charged. I guess other locations may have less reliable grids than I do, but I've only experienced one power outage that lasted so long[1] that our food went off in my entire 40 years living in the Twin Cities area.

        [1] About 96 hours, major storm took down a ton of trees through the whole metro area that took days to clear.

        • Aachen 24 minutes ago
          The device's primary use would be using excess solar power from during the day, or excess wind on rare occasions. This would just be a nice benefit and I just meant that it doesn't have to keep up with the whole house during an outage to still help out in a pinch
        • microtonal 42 minutes ago
          I can't even remember the last power outage we had that was not self-inflicted (a year ago our old microwave oven permanently tripped the residual current device).

          Also, according to the article, it seems to pay itself back in 11-12 years. I'd rather pay the little extra to not have a huge lithium battery in our appartment that cannot be extinguished with a normal fire extinguisher if it decides to ignite itself.

    • adolph 1 hour ago
      The cost/invasiveness of cutover is dropping. There is a relatively new category called "plug in solar" where the inverter/battery is smart enought to detect, sync and use grid power.

      The Stream system: Connect the device to the grid to enable it to feed power into the grid or draw power from it when solar energy is insufficient. This can be done via a standard home outlet (if permitted), or through a circuit breaker. [0]

      0. https://manuals.ecoflow.com/us/product/stream-ultra?lang=en_...

    • tonymet 1 hour ago
      I disagree. During an outage, you need your fridge and a few other essential items. A novice can plug into the back. The device tells you the load and whether you are exceeding. And you can test it at any time. For $600 you can get started without an electrician.

      it's the easiest, safest , most affordable and most reliable emergency solution ever available.

      • brk 1 hour ago
        For a relatively small battery like that, it's not going to last for days. In the typical outage where that battery would carry you, you can typically just leave the fridge closed and it will stay cold enough to prevent 99% of your stuff from spoiling. For most people (at least the US), it's not super easy to get at the plug in the back of the fridge anyway.

        Running HVAC is usually more of a concern, especially in winter or peak of summer, and those aren't device that you can hot-plug, and a small battery wouldn't help there anyway.

        I like the idea of whole-house batteries, but to really make it practical you're talking about thousands of dollars to the battery, install, etc. And you still don't have extensive run time, which is why I think you see most people still leaning towards permanent or portable generators way more than batteries.

        • jerf 1 hour ago
          People need to make decisions about how much resiliency they want. A medium-sized battery greatly enhances your options in an outage. A "solar generator" expands them yet farther. A whole-house generator somewhat farther. It's a lot easier and cheaper if you don't insist that your "resiliency" be "I live my life with no compromises whatsoever".

          But I would advocate that "zero resiliency" needs to be seen as being socially irresponsible. It is socially irresponsible that as soon as a service goes out that you are immediately in an emergency. You should not offload basic resiliency on to emergency services. Yes, if you take a direct hit from a tornado you're going to be leaning on emergency services, but the house a quarter mile from touchdown that may be out for three or four days needs to be able to deal with that. If nothing else, emergency supplies are a lot cheaper when it's not an emergency.

          Don't let the perfect be the enemy of the good, and especially so when perfect is so much more expensive and so much less relevant than the good.

          • munificent 1 hour ago
            > It is socially irresponsible that as soon as a service goes out that you are immediately in an emergency. You should not offload basic resiliency on to emergency services.

            Sure, but that's not a remotely accurate description of a house without a backup battery or generator.

            I grew up in hurricane country and weathered many bad storms. Losing power does not put you immediately in an emergency. If you don't open the fridge much, your perishables will last a couple of days. Non-perishables will last much longer. Having a battery is the difference between "we can hang out and grill dinner for 5 days before we need to hit the road" and "we can hang out and grill dinner for 6 days before we need to hit the road". That distinction does not significantly change your strategy.

            Losing water is a much bigger emergency but is thankfully rarer and a backup battery won't help.

            Climate change will change this story somewhat in the South. If you are in a very hot climate, elderly, or have other health issues, then losing electricity and air conditioning in the summer can be an immediate emergency. Again, though, A/Cs consume so much electricity that a backup battery won't help you much.

            I think you're significantly overestimating the emergency value of a battery backup. Loss of electricity is rarely a rapid emergency. In cases where it is, a generator will at least give you as much power as you care to store fuel.

            • jerf 23 minutes ago
              > > It is socially irresponsible that as soon as a service goes out that you are immediately in an emergency. You should not offload basic resiliency on to emergency services.

              > Sure, but that's not a remotely accurate description of a house without a backup battery or generator.

              I don't mean it as one. Resiliency is my end goal, and "a reasonable amount" at that, not "I can reboot civilization from the zombie hordes with just what is in my shed". If you are already resilient with just a house and what it will naturally do without power, hey, great. A battery opens up options, but if it is not worth it, it isn't worth it.

              It should be a social expectation that you can survive a reasonable 2-3 power and whatever other service outage you have without draining the stores or drawing on emergency services. I do not care exactly how you achieve that.

            • tonymet 58 minutes ago
              Generators don’t work that well. They need regular use and maintenance. Fuel storage is complicated (you will need 30+ gallons a day, or about 2 sedan tank’s worth. Connecting to your panel is expensive at least $2k+. They are smelly and noisy. And if it’s a real emergency, everyone will know you have one , and eventually come knocking.

              For $2k you can buy 3 Ankers and distribute around the house. With a propane camp stove you can cook. So the only utility failing during a power outage is your air conn. If it’s winter you can run a gas fireplace to keep warm.

              In my area we have power outages in the fall and winter wind storms due to trees falling. We need electricity for the fridge, fireplace, lighting , internet & devices. Lithium batteries work great. We get a few outages every season, usually for 2-6 hours .

              My neighbors have a generator for “emergencies” and don’t end up using it because it’s such a PITA. He has it for SHTF, but then he will have to consume the gas from his cars (and siphon it), which means making the decision between home comfort and evac.

              My point is that every solution covers a range of scenarios based on convenience, cost, resilience, versatility and more. There is no one size fits all .

              And now these lithium battery backups provide a broad amount of coverage that is safe and convenient for novices to run.

        • apercu 1 hour ago
          Fair, but I live in a wooded, semi-rural area and have had 7 outages this year, with one lasting over 8 hours.
        • tonymet 1 hour ago
          sure we can quibble over convenience, but it's an outage, and you have to make it work. Look at the testing for the Anker Solix S2000 they are getting 2+ days of regular refrigerator use , which is what people care about primarily .

          What other option is easier or more affordable? A generator has to remain outside, so it needs panel connection ($$) , lots of extensions ( $, hassle), needs a generous fuel supply, and regular maintenance.

          And plug-in solar is becoming legal in the usa. within 3 years everyone will be running these little things, and you'll come around.

      • isoprophlex 55 minutes ago
        I really get where you're coming from, but I'm approaching this from the ~$1500, 5 kWh battery in TFA, which weights 50-60 kg, should be installed somewhere out of the way in a non-fire-hazardous manner. They're great, they can load-shift a meaningful chunk of daily consumption for most european homes don't just move these around to your freezer. They don't magically make you independent in case of grid failures, it's just not what they're for. And to get the average consumer to adopt these, the messaging about what they can and can't do should be crystal clear.
    • apercu 1 hour ago
      I mean, yes and no. Switching your whole house over automatically? Yeah, ok, that can get invasive and expensive. Running an extension cord from a battery/inverter or generator a multiport plug then to to your fridge, router and a couple of lights? That's about 5-10 minutes of effort.

      There's a pretty massive middle ground between "plug in a battery" and "rewire the house.

      • bluGill 23 minutes ago
        Switching the whole house is cheap compared to the generator or battery needed to run everything in the house. Of you can't run everything then you may as well have nothing. The important things need a lot of power.
    • fhdkweig 1 hour ago
      If a fridge is your only concern, they make UPSes specifically for fridges.

      https://duckduckgo.com/?q=Uninterruptible+power+supply+refri...

  • balderdash 1 hour ago
    11-13yr payback on something that is going to degrade ~3-4%/yr for 10 years (and limited terminal value) doesn't seem like the greatest investment unless you think the arb is going to widen a ton.
    • homebessguy 6 minutes ago
      Alternative systems are closer to 5 years payback if you have access to off peak energy. 3-4%/year degradation is very high, battery packs available in the UK from Fogstar are rated at 8,000 cycles with a 95% depth of discharge.

      FWIW my high voltage battery pack has almost 365 cycles and is still at 100% state of health.

    • mosselman 15 minutes ago
      Let's assume the calculation is correct and you actually earn back in 11-13 years. You are better off investing the money in something like the S&P 500 where you'd double your investment in about a decade without the hassle.

      Things will start to get interesting where €1600 don't buy you 5kWh but double or triple the amount.

      I can imagine most people are better off either investing like I said or in insulation.

      • poisonborz 8 minutes ago
        But that makes you more dependent on externalities, a battery makes you more independent instead.
    • sdthjbvuiiijbb 58 minutes ago
      And any arbitrage is also trivially exploited by the electricity company, who has a much greater financial incentive and scale, so there's really no reason to think that it's going to widen in the future either.
      • delecti 21 minutes ago
        Until grid-scale batteries are more established, you're helping the electric company, and that's why they're exposing the arbitrage. They're providing the incentives to nudge demand, so a home battery is doing exactly what they want (use more at time X, use less at time Y). Otherwise they'd just have the 24/7 price be whatever it currently costs when the supply and demand curves are tightest for them (when demand is highest and/or supply is lowest).
      • bluGill 21 minutes ago
        You could exploit it yourself, but only if you have several million to invest, less than that and it isn't worth the bother for the electric company to talk to you. Even at ten million invested you really need to have this is round one in your proposal with the understanding you intend to invest a lot more when it proves in the real world to work like you expect.
  • scaredreally 59 minutes ago
    At my mother's workplace, there was a group of coworkers who each donated an amount of money per paycheck. Each paycheck, one coworker would get the lump sum that was collected for that paycheck. Similar concept to the one described here. They called it "susu" or something to that effect. If I remember correctly, it got messy when people would leave the workplace or when, occasionally, someone would get robbed on the way home.
    • mtlynch 4 minutes ago
      I read the book Poor Economics[0] around when it came out, and it described something similar.

      For people who don't have access to banks, they form "savings clubs" where there will be, say, 12 people who put in $100 per month, and one person takes the pot every month. The idea is that if you keep the money yourself, then you're socially pressured to spend it when there are holidays or guests, but if it's locked up in the savings club, you can't spend it, and then you get a big lump sum to spend on a large purchase that would be otherwise hard to save for.

      [0] https://en.wikipedia.org/wiki/Poor_Economics

  • jerlam 1 hour ago
    > 2. Confirm that their home, meter, and electricity contract are compatible.

    This seems like the hardest step. The costs of "just a battery" are much lower by comparison.

    • jandrese 1 hour ago
      You don't necessarily need to export power, especially for a small battery like tihs. Charge it up when power is cheap, and then configure it to discharge when power is expensive but only to match your current usage. You will need a CT on your main feed for it to balance against, but it can be done.
  • or_am_i 1 hour ago
    How does 12 years required for this scheme to pay for itself stack up against the typical house battery's lifetime?
    • Retr0id 1 hour ago
      Also, as more batteries get added to the grid, the difference between the "cheap" and "expensive" energy prices ought to reduce.
      • rsynnott 1 hour ago
        Eh, there’s a tension there, becuase on the other hand as more renewable power is added to the grid, you’d expect divergence. Especially in countries which are letting people buy at spot price; that can be horribly expensive, or go _negative_.
    • strbean 1 hour ago
      Sounds like that's roughly the average usable lifetime for the battery, so you will break even on average.
      • hobo123 27 minutes ago
        I think most electric car batteries are still at over 80% capacity after 10 years usage, so hopefully you can use them much longer than that.

        If you only cycle then in the 20-80% range, they'll last much longer (at least for NMC cells, not sure how LFP works).

      • Toutouxc 1 hour ago
        Roughly the usable lifetime? Based on what?
  • imbusy111 16 minutes ago
    The hybrid inverter that allows you to plug the battery into your house circuit (DC -> AC) seamlessly is around $2-3k + installation cost, cause you're touching the main panel. Why isn't that in the calculation?
    • domenkozar 15 minutes ago
      You plug it into a socket.
  • Tepix 1 hour ago
    > €1,600 for 5 kWh

    Those prices are high. You can get 2.56kWh for 270€ on Aliexpress, delivered locally from Germany.

    • markvdb 14 minutes ago
      Most of these are illegal to install in Belgium though. Anything connected there needs national grid type approval.
    • microtonal 39 minutes ago
      2.56kWh for 270€ on Aliexpress

      What could possibly go wrong? The things that people do.

      Personally, I'd like the company to be in the EU so that I can at least sue them if it burns down the house.

  • _ink_ 21 minutes ago
    Germany is unfortunately not a good place to do this. The additional fees that you need to pay on top of the actual energy price are simply too high. And currently there is Katharina Reiche in charge which is actively fighting concepts like Energy Sharing.
  • hobo123 33 minutes ago
    Strange article, even though the idea is nice. $200 birthday presents might be a thing in America in some circles, but for German standards that is ludicrous (even 50 bucks is quite a lot, and then you need 32 people).

    I also don't get his example calculation. He mentions that average price in Germany is 38c/kWh, but in the table it's suddenly 4c min vs 13c max (or 40 vs 133?). That doesn't compute.

  • SubiculumCode 43 minutes ago
    People don't tend to buy people large furniture because it's rude to assume that theyll want to keep something large and relatively permanent, much less something that requires an electrician to install.
  • Johnny555 31 minutes ago
    >thirty-two people contribute €50 each.

    I guess Europeans have more friends than Americans -- I can't think of 32 people I'd invite to a birthday party, and certainly not 32 people that I'd expect to give me a €50 gift. I haven't received a real birthday present from friends (beyond a cheap gag-gift) in decades.

  • mistivia 35 minutes ago
    I don't think installing this kind of system at home is a good idea, especially considering the risk of fire. The amount of energy contained in a 5 kWh lithium battery is terrifing.
  • hypfer 53 minutes ago
    A Marstek Venus A 2.12kWh expansion module currently costs 180€ with a bunch of special aliexpress discounts.

    The whole system is.. not great, but it's even cheaper to have a battery than this post makes it sound.

  • sailfast 1 hour ago
    The 12 year payoff IF you manage the arbitrage properly really made me wonder why on earth you would buy one of these.

    I want one, yes. But it sure as hell wouldn't be to save money. It'd be to have something if and when the grid falls over due to negligence.

  • ortusdux 1 hour ago
    This is what government subsidies/rebates are for - https://news.ycombinator.com/item?id=49298910

    Gift should be ... gifts

  • thraway3837 1 hour ago
    You don't really need this, if you have an EV with V2X technology. There's already charging products that work seamlessly: https://www.youtube.com/watch?v=H0WGl_U5azs and you have 100kWh of capacity, so you could sit out an outage for a long time. You can also configure the % cut off for the EV, so you still have enough left to drive if you need to leave.

    EV battery degradation from this use case is irrelevant. EVs are consistently hitting 300,000 miles with 90% capacity, so let's not belabor this point.

    • adolph 12 minutes ago
      The thing about the EcoFlow Stream is that has things like phase alignment which allows it to be plugged directly into a household outlet without transfer switches to segregate grid phase from the phase of power created by the V2X inverter's phase. It also handles solar input.

      I suppose that future V2X systems will incorporate direct plug-in tech, but note the transfer switch used by the system in the video.

    • hypfer 23 minutes ago
      > EV battery degradation from this use case is irrelevant.

      Nope.

  • kortzeus 57 minutes ago
    The only downside is that the battery won't last 11 years with daily usage
  • archydeb 1 hour ago
    And if you’re in the UK, wire them up to Axle Energy

    (plug-in batteries aren’t actually legal here yet, but likely to become so next year!)

  • chaostheory 30 minutes ago
    As the post already mentioned, also great for blackouts, of which more are coming for the developed world given climate change and infrastructure failure
  • vel0city 39 minutes ago
    So I could buy a battery for ~$1,850 today that won't even break even in a decade (and hope everything goes well with this plan, not guaranteed in the slightest), or I can buy a 10 year US treasury note that'll give me another $1,000+ in profit at the end of the decade.

    Remind me why I should buy the battery? It clearly can't be because it makes financial sense to just have the battery.

  • tristor 44 minutes ago
    This is interesting, but is 3kW enough to be useful? What is the latest when it comes to home batteries? Has management gotten better to be smarter?
  • mindslight 1 hour ago
    Call me old fashioned, but I just bring a can of gasoline and a pile of super soakers.

    While I do like the idea in theory, I don't love the inherent nudge towards off the shelf productized energy storage that will be placed somewhere without much of a plan, and then basically invites rewiring with extension cords. I get how those things are appealing for camping or determined apartment DIYers at the like, but moving them from a seek-them-out "pull" dynamic to a here-you-go "push" dynamic seems like asking for problems from people not thinking too much about storing 5kWh.

  • well_ackshually 1 hour ago
    >sixteen people contribute €100 each;

    yeah sure everyone has 100€ to spend on friends, at least once a month.

    What kind of reality does he live in ?

    • Terr_ 51 minutes ago
      Yeah, TFA is basically a €1600 (~$1850 USD) unofficial mutual loan proposal. It implies that:

      1. You and all your friends have houses.

      2. You and all your friends are confident investing €1600 this year in a home-upgrade.

      3. You and all your friends aren't worried that a badly-structured €1600 loan could somehow hurt your friendships.

      Even if we assume the first two, how rich do you need to be for #3? That's like... 3% of the median pre-tax German salary.

      Personally, I do not want my friend group to be a financing-scheme, and if I wanted a financing scheme I'd use something that didn't explode when someone chooses (or is forced by circumstance) to exit with a non-zero balance.

      I could understand friends having good-years helping out ones having bad-years ("banqueting" [0]) but what's being proposed doesn't have those conditions or timescales.

      [0] https://acoup.blog/2020/07/24/collections-bread-how-did-they...

    • atombender 40 minutes ago
      And everyone lives in a house that they own, apparently.
      • hobo123 24 minutes ago
        Why can't renters plug a battery into their socket, too? As long as the electric house grid is rated for the specified power (might not be the case on some countries, or in extremely old homes).
        • atombender 5 minutes ago
          I'm not an expert. But a Tesla Powerwall type battery is a big thing to install for a renter, is it not? I would argue it's more than installing, say, a washer or window AC; probably more like installing a wall heat pump?

          You would certainly need the owner's permission, and investing in the kind of adaptations needed might not be something most renters are interested in when it's not their own place. A battery has to be integrated into the whole electrical feed, and a responsible owner might insist that this is a permanent installation and something you can just take with you when you leave. Or if you do, undoing the install will be similarly costly. And who knows if your next place will allow you to install a battery as well.

          I don't think you can realistically install it in an apartment, due to fire regulations, and it needs a lot of space. Personally, I live in a 74 m2 apartment, and there's simply no room anywhere. Wiring is another matter; electricity comes through shared risers I don't control.

    • Hugsbox 1 hour ago
      You're getting downvoted, but for real this is so disconnected from what I'd say is feasible for most people. I and most of the people I know live squarely paycheck to paycheck, I can't afford to buy my friends birthday presents at all, let alone set aside that much per month just to put batteries in other peoples' houses. This feels like one of those things where the author doesn't grasp the privilege he lives with.
      • Majestic121 1 hour ago
        Surely not for _most_ people, but for people on Hacker News, in the correct age range to have a house, putting 100e aside really does not seem out of whack.

        Maybe the author is privileged and it's fine, it's not because you personally can't afford any gift that the author is disconnected, he might not just be talking to everyone on earth.

        • Johnny555 29 minutes ago
          I think the people that can easily put aside €100 for the birthdays of a dozen or more friends could also just pay the €1600 and buy the battery for themselves outright without having to wait for a birthday "surprise"
      • Symbiote 1 hour ago
        Even where people probably could afford it I think spending €100 on a birthday gift would be excessive. It would be showing off.
      • Tepix 1 hour ago
        Do they even have houses?
        • ssl-3 1 hour ago
          Does having a home inherently change disposable income?
        • Hugsbox 1 hour ago
          In some cases yes, and they're not doing much better than I am.
  • wheatone 2 hours ago
    [flagged]
    • beaviskhan 1 hour ago
      Most modern batteries like this are weatherproof and can be mounted outside the home. Most modern batteries use LiFePO4 chemistry, which while not perfect, is much less risky in terms of thermal runaway than older lithium ion batteries.
    • fhdkweig 1 hour ago
      The Tesla Powerwall is only slightly larger than a pizza box and can be mounted directly on the wall. Most of the below images are outside the house, but some are also in the garage.

      https://duckduckgo.com/?q=tesla+powerwall&ia=images&iax=imag...

      • ykl 1 hour ago
        I have two Powerwalls mounted on my house and while I think they're fantastic and pretty compact for what they are, I would not describe them as anywhere near the size of a pizza box (unless you mean one of these things [1]).

        [1] https://www.scottspizzatours.com/blog/worlds-largest-deliver...

      • thejazzman 1 hour ago
        Tesla powerwall is 44” x 24”

        Where are you buying your pizzas?!

    • domenkozar 1 hour ago
      This battery uses a safer type of lithium chemistry that is less prone to overheating, though no large battery is risk-free. Water is used by firefighters to cool battery fires (they can reignite tho).

      Install it outdoors or in a detached garage, away from anything flammable. Never in a bedroom, hallway, or escape route.

      There are newer batteries tech that can't inflame.

  • toomuchtodo 2 hours ago
    Great piece and post, love the concept!
  • Apreche 1 hour ago
    Anyone who can afford to own a home can afford their batteries and doesn’t need gifts. Renters are not allowed to modify their home in such a way.
    • Tepix 1 hour ago
      In Germany you can use a "Balkonkraftwerk" that just plugs into any outlet and contributes up to 800W. You can also hook up solar panels to it up to 2000W (makes most sense with batteries). No need for the landlord to agree.
  • jambalaya8 1 hour ago
    No.