Comment by ianferrel
2 days ago
>the solution came with rearranging and adjusting the cells to ensure the packs worked more efficiently.
>Glubux even began disassembling entire laptop batteries, removing individual cells and organizing them into custom racks. This task, which likely required a great deal of manual labor and technical knowledge, was key to making the system work effectively and sustainably.
This kind of thing is cool as a passion project, but it really just highlights how efficient the modern supply chain is. If you have the skills of a professional electrician, you too can spend hundreds of hours building a home battery system you could just buy for $20k, but is less reliable.
> spend hundreds of hours building a home battery system
That is, in my opinion, the worst feature of this entire project. It is cool and nice and fun. But it takes a lot of time to research, acquire skills, get tools and build.
> you could just buy for $20k
I agree with a broader point but that particular price is extremely high and far from reality.
A reasonably good 18650 cell has a capacity of ~12 Wh (~3300 mAh * ~3.7 V = ~12.2 Wh). The battery mentioned in the article consists of "more than 1000" such cells. Let us assume 1200 cells. That would mean it has a capacity of ~14.4 kWh (1200 * 12).
It is possible to get a pre-assembled steel battery case on heavy-duty wheels for 16 LiFePo cells, with a modern BMS with Bluetooth and wired communication options, a touchscreen display, a circuit breaker and nice terminals for ~ $500. And it is also possible to get 16 high quality LiFePo cells with a capacity of ~300 Ah each, like EVE MB31, for significantly less than $100 each. This means that for less than ~$2000, it is possible to get all components required to assemble a fully working ~15 kWh LiFePo battery.
- That assembly would take a few hours rather than weeks.
- It will have new cells rather than used ones.
- It will be safer to use than a battery with Li-Ion cells.
- It will likely take much less space.
- It will be easy to expand.
Now.
I will point out that in 2016 when they started this project, the cost of new batteries would have been multiple times higher than it is today, so it would have been a moderately more "sensible" thing to do than it currently seems.
Yes, of course, this cost consideration is only relevant today.
I can imagine that ~9 years ago there might have been very little reasonably priced LiFePO4 cells available and if someone could get their hands on used 18650 cells very cheaply, it might have been a reasonable choice at the time.
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Now what?
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Thanks for the all the specifics! I admit that my $20k number was a very rough "I'm sure it must be less than this" estimate because I wanted to make sure I erred on the high side for the point I was making.
The parable of the fisherman and the banker:
https://travis.vc/mexican-fisherman-parable/
Sometimes the doing is the fun part.
> - It will have new cells rather than used ones.
This is not a feature. Our Earth is a limited resource, and being able to reuse batteries instead of discarding them to the trash is a desirable property.
There's even more to the riddle. Lithium recycling, cost of the power loss in old cells. Power transmit cost. Cost of power generation on site.
Pick used EV or industrial batteries. This must be much more efficient due to a larger cell size than in laptops.
OTOH used laptop batteries can likely be obtained for effectively zero monetary cost, while used EV or solar backup batteries still cost quite noticeable money per kWh. With laptop batteries, you pay with your time; if you for some reason have an excess supply thereof, or you just enjoy this kind of work as a pastime.
> Our Earth is a limited resource
Of course. No one disputes that. I was just trying to point out that you can get better cells for less money.
> being able to reuse batteries instead of discarding them to the trash is a desirable property
I fully agree. No one is trying to suggest that we should discard used batteries into trash.
We have LOTS of lithium
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300 Ah * 3.2 V => 960 Wh ~= 1 kWh
$80 per cell (before shipping) on the top Google product result for EVE MB31.
That's a good bit cheaper even than when I looked last, in early 2021.
And there's a non-zero possibility he burns his house down and doesn't have anyone to sue over it.
At least if he bought a commercial battery and it experiences a lithium fire, he might expect to file a claim against the manufacturer, or his insurance company might on his behalf.
You can get 15 kWh for $1,3000 if you pick up in Texas (these use EVE MB31 which usually end up testing at ~310 Ah): https://www.apexiummall.com/index.php?route=product/product&...
It just keeps getting cheaper and cheaper every year...
What 13000? Here in the EU we pay around 3-3.5K for 15 kWh.
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$1,300.00
typo sorry, $1,300.00
13k or 1.3k?
$20K for a home battery backup for someone capable of doing DIY would be far larger than what I assume he has built here. AFAIK the cheaper end is around $340 (2016) per kWh at 20 kWh that would be $6,800. In 2025 at $100 per kWh it would be $2K. If it's worth it would largely depending on a persons post tax required rate of return and how long it would take.
I spent almost as much as that for a 2 Powerwalls and installation in 2019. (Granted, I got a 3rd back from various incentives that probably weren't available for DIY.)
DIY (like this project) is only "worth it" if the person doing it enjoys the work or values the lessons.
There is a spectrum of DIY and the sweet spot depends on the person. Since I'm good with electronics my sweet spot is buying premade packs.
If you took that same time, and invested it in working at Target, or Amazon etc, would you have more or less money than it would cost to buy an off-the-shelf battery? There are obviously other pros and cons.
I think Target isn't the right comparison here - the skills required for this project are worth much more than minimum wage bagging groceries. If you assume something like $50 an hour (on the low end for a skilled electrician), you get to the $6800 number in the parent post pretty quickly.
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Of the three options, DIY battery packs, premade 100aH battery packs, or white glove powerwall a minimum wage earner would likely not have the skills to DIY the battery packs nor the money to pay for the powerwall.
Battery packs are an efficient market commodity and that’s pretty hard to beat for value for money.
Once full installations become more of a commodity then DIY with premade packs becomes less worth it.
It all comes down to what makes you happy.
That guy who was gaming a bug in the lottery in New England, near as I can figure was making about $20-30 an hour for his troubles. I suspect he may have made more off of selling the movie rights than off of the lottery.
He made more than he would have working retail for sure, but maybe he could have done better with another job if he weren't fixated on sticking it to the Man.
This battery thing feels a bit like the same sort of sentiment.
That said, any task you can do while talking to a friend or binge watching a TV show cannot be accurately accounted for in cost by just how much the clock moved.
There HAS to be a way to automate this process and make it work at scale.
The problem is likely cost effectiveness compared to just replacing a whole group of cells, compared to one single cell. The unit economics of getting the remaining life from single used laptop battery are not very good. There's certainly lots of potential value for someone willing to do the work, if they can afford the opportunity cost, or if a business can source extremely dirt cheap cells and cheap high skilled labor.
You would be amazed how many battery packs are multiple 18650s in a trenchcoat. Even EV battery packs use them. Though it does raise the question - wouldn't an old EV battery be a better solution than stripping apart laptops?
There's a lot that goes into manufacturing battery packs beyond the cells. How's your thermal path to ambient in your home wall battery? How is the inter-cell thermal isolation? Is there a path for gas discharge in the event of a cell failure? Is the pack appropriately fused at the cell or module level? When a cell fails, does it take the whole pack with it, catch someone's apartment building on fire and kill a family of 5, or merely become stinky with a hotspot visible on IR?
How good is your cell acceptance testing? Do you do X-ray inspection for defects, do ESR vs cycle and potentially destructive testing on a sample of each lot? When a module fails health checks in the field, will you know which customers to proactively contact, and which vendor to reassess?
Yeah lots of batteries are 18650/26650 in a trenchcoat. The trenchcoats run the gamut from "good, fine" to "you will die of smoke inhalation and have a closed casket" in quality and I think that bears mentioning.
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Probably, but EV batteries are large enough that there might be an industrial recycling process for them, while old laptop batteries are basically free because it's too much labor to extract useful value from them.
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> You would be amazed how many battery packs are multiple 18650s in a trenchcoat
Also laptop batteries used to be many (usually three or six) 18650s in a plastic trenchcoat.
You could literally rebuild your battery when it died, and pick the cells you liked the most. In theory you could pick higher-quality cells than those you find in the batteries sold on ebay from chinese stores. In theory.
>You would be amazed how many battery packs are multiple 18650s in a trenchcoat
$50 of 18650s in a $500 trenchcoat with DRM protection. So wasteful.
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That depends on the problem you're trying to solve. If it's only to build a home power system, sure, but if the goal is "I want to prevent these laptop batteries from ending up in a landfill" then using an old EV battery doesn't really help you much.
FWIW a lot of EVs use prismatic cells, not cylinder cells. Tesla, Rivian, and Lucid use cylindrical cells. Hyundai, Volkswagen, BMW, GM, Ford, and BYD all use prismatic cells.
There is a lot of liability in sticking your name on a hodge podge of random used lithium cells.
I feel like for home battery backup there needs to be some kind of lower energy density solution that has zero fire risk.
Weight is not a factor for home energy storage, there is no need for lithium cells.
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Yes, with cheap third world labour, the same way many other technological marvels of the modern era are "automated".
This can't be done remote so you will need to bring that labor to where the work is.
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You would never do this in a production product. You need batteries with similar internal impedances or undesirable things happen. This is the battery equivalent of the guy who welds two car front ends together and drives it around. It's cool and quirky but not a useful product for most people.
From what I've heard, it is more economical to recycle the raw materials than to reuse small packs.
Reuse of vehicle sized packs seems to be pretty common, though. I'd guess that a DIY home backup could be built pretty easily from used vehicle batteries.
The dude has a warehouse/workshop to do this work and house the system. I’m super impressed by what he’s accomplished, don’t get me wrong; but, what he’s done just isn’t viable for 99.99999999999% of people.
Give me an array and battery system that can pull off the grid and/or array and power most of my home without me having to think a whole lot or pay a vendor thousands to install while making the total cost under $1000 and I’ll do it.
Until then, it just isn’t financially viable when my electricity costs are well under $70/month average across the year.
Recouping the costs for install of solar systems are estimated at 30-40 years as of 4 years ago when I researched it. I’m sorry, but that’s just not worth it for me and most others.
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Buying a used Nissan Leaf and using V2H feature in CHAdeMO is it. Or you can remove and use its well-reverse-engineered minimum nominal 24kWh semi-removable battery. But no one wants a Leaf, so there's that.
Of course, but you will also 'scale' the safety implications.
Standardizing battery packs would probably help with the automation; like with USB-C.
Isn't the problem with parasitic charging? Suppose you had a bunch of used 18650 cells. To scale the electronics, they'll be wired up in parallel and/or series so the charging logic can be shared, but since the batteries are wildly mismatched, it results in parasitic charging.
That is why you sort them.
Some recent research into that: https://www.sae.org/publications/technical-papers/content/20...
You can also consider maintaining packs together to avoid complicated disassembling processes.
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But will the scale justify the huge investment?
You can read it the other way around: with labour and knowledge, you can save $20k.
And with even more passion and commitment and with business skills, you could earn $20k at a time.
> but it really just highlights how efficient the modern supply chain is
This "efficiency" relies on the assumption of writing off the entire battery set at sale. That's not impressive at all.