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Buy Your Friends Batteries

https://domenkozar.com/2026/08/17/buy-your-friends-batteries/
44•domenkozar•55m ago

Comments

wheatone•49m ago
May as well be "Buy Your Friends Bombs." given what we've seen with Israel's pager-bomb operation in the MidEast.

Where do people store these things? They're very dangerous once afire! Worse than a can of petrol by far and can't be extinguished with water.

domenkozar•36m 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.

beaviskhan•32m 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•26m 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...

thejazzman•24m ago
Tesla powerwall is 44” x 24”

Where are you buying your pizzas?!

ykl•13m 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...

toomuchtodo•43m ago
Great piece and post, love the concept!
domenkozar•36m ago
Let's go!
Retr0id•36m 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.

domenkozar•31m ago
That's step one, next is your friends.
cbarnes99•29m 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.
oytis•24m ago
But then you still have to buy birthday presents on top of that
Retr0id•21m 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).
blitzar•17m ago
Might as well just have an annual theme every year and try to negotiate a bulk discount.
Apreche•31m 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•5m 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.
well_ackshually•30m 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 ?

Hugsbox•5m 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.
isoprophlex•30m 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.

fhdkweig•23m ago
If a fridge is your only concern, they make UPSes specifically for fridges.

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

tonymet•23m 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•16m 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.

or_am_i•28m ago
How does 12 years required for this scheme to pay for itself stack up against the typical house battery's lifetime?
strbean•25m ago
Sounds like that's roughly the average usable lifetime for the battery, so you will break even on average.
Retr0id•23m ago
Also, as more batteries get added to the grid, the difference between the "cheap" and "expensive" energy prices ought to reduce.
rsynnott•4m 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_.
jerlam•28m 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.

archydeb•18m 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!)

mindslight•13m ago
Call me old fashioned, but I just bring a can of gasoline and a pile of super soakers.

While I 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.

Tepix•7m ago
> €1,600 for 5 kWh

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

jambalaya8•6m ago
No.
toomuchtodo•8m 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 lots of clean energy, and needs all the storage it can get (residential, commercial, utility scale) to convert curtailment into realized clean energy offsetting potential fossil energy usage.

Solar Power Is So Big in Europe That Electricity Is Being Wasted - https://www.bloomberg.com/news/articles/2026-05-13/europe-so... - 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.

benj111•6m 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?

jerf•10m 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.

tonymet•9m 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.

Aachen•19m 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
EvanAnderson•10m 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).

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