AustinPowerWall Project

dcbartlett

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Joined
Oct 8, 2017
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Kicking this build off with few batteries...literally 2. Looking at building a powerwall capable of powering an EV car. We'll see where it goes from there.

Looking to do a multi-block setup with batrium. This will probably be a ~120 volt kit so that i can also charge it directlyvia mains for now (in an apartment and can't do solar) without a lot of hassle. Car would run on ~120 volt as well.

If anyone has advice, i'm more than happy to listen.

Current battery collection is below.


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Just because ur battery bank is 120V that doesnt make it doable to charge it just by plugging it into mains. You still need a charge-controller that takes AC to DC and correct voltage and current.

You better start collecting. For car you need alot :)
Welcome!
 
Oh i know i need a charge controller to convert from AC to DC. That's planned. The main reason is the ease of charging the car. 120 DC to 120 DC is fairly easy. The Car would be powered by 2 warp11 motors running at 120 volts.

Thanks for pointing that out though. :D

Lots of batteries to go get now.
 
Remembered i had some old laptop batteries. Tore one down, got one to go.


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Now i have more batteries. Also found a box to use as a make shift temp case.


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I managed to nick a few of the battery casings when getting the spot welded aluminum off. Should i re-shrink wrap them?
 
Of course. if they test fine, rewrap. Toochi has some really nice wrap. I haven't had a chance to use the ones I got, but several others have used and liked them. Many colors, too.
 
Found a few more batteries to tear down. Up to 21 cells now. Gonna have to find a way to test these soon. Wanting to get my hardware out and build something that can do this automatically and record the data for me. I have some programming experience (about 17 years of it) so i'm sure i can whip up an application for that.

Whats the best way to test a battery? I'm thinking i'll do a full drain of batteries. Then do a charge cycle and measure its input. Then a full discharge again and measure the output. Then charge it back up to 4.0 and count it as ready. Anyone have a good charging strategy for this?


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Startin off small. Don't worry, they build up quickly :)

hrmm, you're going to do a capacity check on charge and discharge. Interesting. Probably do a discharge then charge testing that way when you do your initial charge, you can weed out problem cells and not waste the extra time it takes to discharge and recharge anyways. You want to precharge for several reasons.
Primarily to weed out problem cells, Secondly get them prepared for testing, Thirdly, hrmm, I'm sure there's another reason :p

I got in some more parts this weekend and hopefully I can start building the charging/testing bench that MrContentin built. He's provided a lot of data and code on building a working unit. Then just modify to your needs.
 
Korishan said:
Startin off small. Don't worry, they build up quickly :)

hrmm, you're going to do a capacity check on charge and discharge. Interesting. Probably do a discharge then charge testing that way when you do your initial charge, you can weed out problem cells and not waste the extra time it takes to discharge and recharge anyways. You want to precharge for several reasons.
Primarily to weed out problem cells, Secondly get them prepared for testing, Thirdly, hrmm, I'm sure there's another reason :p

I got in some more parts this weekend and hopefully I can start building the charging/testing bench that MrContentin built. He's provided a lot of data and code on building a working unit. Then just modify to your needs.

Yeah, that's probably a better idea. Charge them up to a known voltage, then do a discharge/charge cycle and measure them. That way i don't waste a cycle on the cells.

Do you have a link for that bench by chance? I'd like to read up on it a bit. I also like the circular charger i saw on NERDVille's channel. Might borrow from that idea.
 
Got a few more batteries to tear down. Dell packs, so should have some good batteries in them (if they test good).


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Also, found my first bad cell in a box...surprised it didn't catch fire honestly.


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dcbartlett said:
Yeah, that's probably a better idea. Charge them up to a known voltage, then do a discharge/charge cycle and measure them. That way i don't waste a cycle on the cells.

Do you have a link for that bench by chance? I'd like to read up on it a bit. I also like the circular charger i saw on NERDVille's channel. Might borrow from that idea.

I tend to cycle cells before I test them. If a cell has sat for some time it may gain some capacity after a cycle. I also leave a fully charged cell sit for a week or so, and check for self discharge. Save time testing cells that are not good.
 
Geek said:
dcbartlett said:
Yeah, that's probably a better idea. Charge them up to a known voltage, then do a discharge/charge cycle and measure them. That way i don't waste a cycle on the cells.

Do you have a link for that bench by chance? I'd like to read up on it a bit. I also like the circular charger i saw on NERDVille's channel. Might borrow from that idea.

I tend to cycle cells before I test them. If a cell has sat for some time it may gain some capacity after a cycle. I also leave a fully charged cell sit for a week or so, and check for self discharge. Save time testing cells that are not good.

That's some sound advice. I'll make sure to let them sit so i can check for self-discharge.
 
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