DIY Powerwall 18650 Anyone Here?

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Biren78

Biren78

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My coworker sent this. He's hooked on the idea. Is anyone doing these? Here's the guide How To Build A Mini DIY Powerwall with Maker Batteries – DIY Batteries

And a popular video

Looks like you'd be able to get these Tesla 24V 105Ah Battery Lithium Ion Module 18650 Cells for cheap and make your own without having to do as much engineering. Here's another Tesla one with twice the capacity for twice as much Tesla Model S battery module, 24V, 250Ah, 5.3kWh, 444 Panasonic 18650 3400mAh | eBay

That'd be a killer BBU right? Or for ppl mining.
 
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T_Minus

T_Minus

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That's getting crazy with the Telsa pack!

We used to DIY for RC cars/trucks late 90s early 00s and I recall the battery charger/test/etc equipment easily pushed $500+ to amke sure you were doing it 'right', and a quality battery cell makes a HUGE difference than a 'bargain' one... we used to bulk buy $15 battery packs for kids/family to use, would get about 8-9m runtime, and then the $80 packs would go about 25m but if on throttle too much would start breaking parts ;)

I find it really interesting how the Teslda pack is designed using 444 18650 cells... had no idea they did that, seems a bit strange to me but maybe common cells combined were cheaper than their own design? Giving me some ideas for off-grid setups if possible to score some more of those Teslda batteries :) Hoping for 900-1300AH but that much Lithium batts $10k+ retail, LOL. Looking at those Tesla packs even at 4 of them for 1kAH put it only a grand or so above a 300ah lithium 'large' retail battery (no clue what's in them either).

I wonder if the Teslda cell design allows indiv. cells to die w/out affecting overall performance/usability much vs other designs?? I don't know enough about batts :D and how that tesla is wired.
 
Blinky 42

Blinky 42

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realtomatoes

realtomatoes

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video was taken down.

i did read the DIY article, interesting. odd enough it reminded me of that scene in Quantum of Solace where Bond shot the fuel cells in the desert hotel.
 
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ttabbal

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If you do this, keep in mind that it is obviously not UL listed. That might not sound like much, but if your house burns down the insurance company might be able to use it to avoid paying for it. I don't know how likely that is, but it's worth mentioning so people can go into it aware.

Also, respect these things. One going up isn't a big deal. A pack of hundreds is. Ideally, one would use the management system from the donor car. Those are likely to be well engineered.
 
T_Minus

T_Minus

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ttabbal said:
If you do this, keep in mind that it is obviously not UL listed. That might not sound like much, but if your house burns down the insurance company might be able to use it to avoid paying for it. I don't know how likely that is, but it's worth mentioning so people can go into it aware.

Also, respect these things. One going up isn't a big deal. A pack of hundreds is. Ideally, one would use the management system from the donor car. Those are likely to be well engineered.
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I've been part of numerous automotive/diy/fabrication communities the last 20 years, and a few times a year someone makes a statement like you did about not "UL Listed" or not installed by a "certified professional" or "not up to current code" and the scare of insurance not accepting a claim due to these reasons... and in those years not 1 person has ever been able to find a case that has shown that to be true.

Do you have any proof of insurance denying claims because of something wasn't UL listed, wasn't installed by a certified installer, or wasn't installed up to code? And those were reasons given to deny insurance... I'd still like to get an answer on this.

Where I live people are stupid (said with kindest tone) and often cut down trees themselves very close to home/property to save the 300-500$ a licensed/bonded/arborist would charge, and as you guessed it often lands on the house. I haven't heard of insurance denying these people either. Or the people who leave their pipes open to prevent freezing, forget, then turn the water back on 100% and flood their house.

Not to get too far off topic, but I'm really curious if you've seen any actual claims denied due to any of these reasons, or any other negligence caused by the homeowner, which, IMHO seem to be the most insurance cases there are aside from natural disasters, which of course carry their own additional add-ons/plans/limitations/etc...


Now, regarding insane amount of batteries... DIY with that capacity is scary as heck and I'm with you, I'd def. want to use a proven, reliable management/regulation system. Ideally a redundant system because I've heard about 10k$+ Lithium packs becoming useless because of the charge method got stuck, or they went to trickle instead of 100% off, etc... IMHO, lithium has a year or two more to go so installers/professionals can understand them more outside of their Automotive and high-end/niche home/boat installs. Right now that info is valuable (read: $$). Not saying it's not out there but it's very hard to compare equipment, setups, etc, when there's very few people dealing with 500AH+ capacity at 12-48v.

I think it would be cool if people had LINKS/URLS to DIY Lithium Packs for home backup, etc... :) Def. an area I plan to work with in the next 24 months.
 
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ttabbal

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I don't, and I tried to make that clear in the post, but perhaps I failed there. I watch a number of renewable energy developments and that is something I've seen people mention, also without citations, when discussing this sort of thing. My point, perhaps poorly made, was that one should consider it as a possibility and perhaps discuss it with your insurance agent/company/lawyer/etc.. I called my agent when I put solar panels on the house. If nothing else, I want them covered if there is a problem. I also wanted to make sure that other coverage is unaffected by the addition.

I also found the posts I've read more than a little vague as the same people will then post elsewhere about building a 2 kAh lead-acid pack with no qualms about such issues. I personally don't see why the chemistry should matter, a DIY battery is a DIY battery to me. Sure, lead and nickel chemistries are less likely to start a fire, but they can cause problems. If nothing else, any big DC source should be given respect. I would say lithium deserves a bit extra as the internal resistance is very low compared to others. Due to that, they can source a stupid high current level. I know some people are using these set up for 48V, that's less of an issue. But some designs I've seen use >300V for DC coupling applications. That level requires a bit more care.

For clarity, I haven't seen an actual build of a HVDC setup, just talk. The builds I've read about seem to run 12/24/48V, possibly to work with existing inverters and such.
 
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Chuntzu

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T_Minus said:
I've been part of numerous automotive/diy/fabrication communities the last 20 years, and a few times a year someone makes a statement like you did about not "UL Listed" or not installed by a "certified professional" or "not up to current code" and the scare of insurance not accepting a claim due to these reasons... and in those years not 1 person has ever been able to find a case that has shown that to be true.

Do you have any proof of insurance denying claims because of something wasn't UL listed, wasn't installed by a certified installer, or wasn't installed up to code? And those were reasons given to deny insurance... I'd still like to get an answer on this.

Where I live people are stupid (said with kindest tone) and often cut down trees themselves very close to home/property to save the 300-500$ a licensed/bonded/arborist would charge, and as you guessed it often lands on the house. I haven't heard of insurance denying these people either. Or the people who leave their pipes open to prevent freezing, forget, then turn the water back on 100% and flood their house.

Not to get too far off topic, but I'm really curious if you've seen any actual claims denied due to any of these reasons, or any other negligence caused by the homeowner, which, IMHO seem to be the most insurance cases there are aside from natural disasters, which of course carry their own additional add-ons/plans/limitations/etc...


Now, regarding insane amount of batteries... DIY with that capacity is scary as heck and I'm with you, I'd def. want to use a proven, reliable management/regulation system. Ideally a redundant system because I've heard about 10k$+ Lithium packs becoming useless because of the charge method got stuck, or they went to trickle instead of 100% off, etc... IMHO, lithium has a year or two more to go so installers/professionals can understand them more outside of their Automotive and high-end/niche home/boat installs. Right now that info is valuable (read: $$). Not saying it's not out there but it's very hard to compare equipment, setups, etc, when there's very few people dealing with 500AH+ capacity at 12-48v.

I think it would be cool if people had LINKS/URLS to DIY Lithium Packs for home backup, etc... :) Def. an area I plan to work with in the next 24 months.
Click to expand...
I have been building ebikes and diy battery packs for a year now and it's been alot of fun. The Tesla packs are super easy to use and have great desity. Also when buying large quantities the dollar per cell gets pretty low which is nice. But to be totally honest unless harvesting free cells it tends to work out eaiser, not necessarily cheaper to just buy a powerwall. Dont get me wrong, I love diy and the cost saving for doing it, but after buying cells, inverter, charge controller the savings isn't huge with the diy powerwall unless harvesting cells. But I like the idea of it. And keep the ideas coming!!!

Sent from my SM-N920T using Tapatalk
 
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nitrobass24

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Patrick said:
@nitrobass24 just for redundancy? I would imagine that costs a lot to run.
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It's for redundancy absolutely, would never run on this instead of electricity just because it's loud and not nearly efficient enough for that use case but it's actually pretty cheap to run.

Natural gas is generally preferred over electricity. All of my appliances including my dryer run on Nat Gas.


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