Just starting my journey, but which way to go?

Drewsifa

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Apr 8, 2021
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7
So I'm just starting my journey, and looking for direction. Which way to go and what do I need? Got some ideas as seen quite a few vids now. Just started to harvest laptop cells. Got a opus BT-3100 charger/tester and a imax b6 balance charger. Then suddenly got my hands on 250 x Bosch indego Li-ion 32.4v, 3Ah, 97.2Wh battery's cheep (i think). Brand new from discontinued line of robot lawn mowers. Each pack has 18 x samsung INR18650-15Q 1500mAh 18650s. What should I do now. power wall maybe. How do i test/charge this pack. Should I keep them together or break them apart. What other equipment do I need to get? Grabbed them with out much thought, hope I did The right thing. Looks like I'll have to sort some kind of BMS and balance leads for 9s2p pack, and imax only does 1-6 cells I believe, unless i brake up the packs. Any suggestions would be most welcome.
 

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floydR

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Get a icharger x12, or icharger 4010duo each can test/charge 9s batteries , yes you can make a powerwall with them. but sooner or later you would have to break the packs up. Many inverters are based on lead acid batteries 12v, 24v, 36v, 48v.12v is not a good fit for inr cells, 24v(7s) is better, 36v (10s) ok not too many inverters for 36v, 48v (14s) is best. If I understand right you have 250 9s2p batteries 4500 18650's 14s300p could potentially yield 21kWh
if my math is right.

Later floyd
 

OffGridInTheCity

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Assuming your goal is a DIY powerwall... then I agree with @floydR - you'll likely reach the conclusion that you need to break out the individual cells and do a standard test process. The problem with so many (small) units is you're limited to their voltage range which is probably not a good match for standard 24v / 48v powewall equipment. You would still need to test each one that the BMS works, mount/hook-them-up, and you don't have any way to monitor them once you put them online.

If you go for 48v, then 4,500cells/14packs = 321cells/pack. 321cells/pack @ 1500mah per cell is 481,500mah * 48v = 23,112,000 watt hours = 23kwh battery bank. If you limit DOD to 60% (for longer life) you could operate in the useable power range of 14kwh/daily-cycle range.

Personally - I'd go for 150'ish cell packs (easier to manipulate) and create 28 packs instead of 14 at 300'ish cells. A lot of pack design has to do with the location you plan to 'fit them in' - e.g. a metal cabinet for fire protection or even a hole in the back yard.... folks do it many different ways but I'd plan out where the powerwall will live up front and measure it out :)
 
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italianuser

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Feb 25, 2020
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... Then suddenly got my hands on 250 x Bosch indego Li-ion 32.4v, 3Ah, 97.2Wh battery's cheep (i think). Brand new ...
You lucky man! Welcome to you, do present yourself in Introduction section of forum (y)
 

Drewsifa

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Apr 8, 2021
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Get a icharger x12, or icharger 4010duo each can test/charge 9s batteries , yes you can make a powerwall with them. but sooner or later you would have to break the packs up. Many inverters are based on lead acid batteries 12v, 24v, 36v, 48v.12v is not a good fit for inr cells, 24v(7s) is better, 36v (10s) ok not too many inverters for 36v, 48v (14s) is best. If I understand right you have 250 9s2p batteries 4500 18650's 14s300p could potentially yield 21kWh
if my math is right.

Later floyd
Thanks mate. I will look into those chargers. haven't come across vids of anyone using these yet. Only 6s using imax B6. Can you suggest any vids on these cheers. Yeah had A Feeling I might have to break apart. Pity as they are nicely packaged. Maybe I can just break off two pair at the end to make into 7s2p. End protection covering cell terminals comes off easy, so possible to stack another pack beside and connect to make 7s4p etc. I have built myself a spot welder and have some nickle strips as well. These dont have a bms or balance wires or fuses, only + , - & what looks like a temperature sensor. what would you suggest? actually sorry looks like a fuse in line on the positive wire.

Thanks Again Drew
 

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Drewsifa

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Apr 8, 2021
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Assuming your goal is a DIY powerwall... then I agree with @floydR - you'll likely reach the conclusion that you need to break out the individual cells and do a standard test process. The problem with so many (small) units is you're limited to their voltage range which is probably not a good match for standard 24v / 48v powewall equipment. You would still need to test each one that the BMS works, mount/hook-them-up, and you don't have any way to monitor them once you put them online.

If you go for 48v, then 4,500cells/14packs = 321cells/pack. 321cells/pack @ 1500mah per cell is 481,500mah * 48v = 23,112,000 watt hours = 23kwh battery bank. If you limit DOD to 60% (for longer life) you could operate in the useable power range of 14kwh/daily-cycle range.

Personally - I'd go for 150'ish cell packs (easier to manipulate) and create 28 packs instead of 14 at 300'ish cells. A lot of pack design has to do with the location you plan to 'fit them in' - e.g. a metal cabinet for fire protection or even a hole in the back yard.... folks do it many different ways but I'd plan out where the powerwall will live up front and measure it out :)
Mate thanks for your reply. unfortunately getting real late, so will have get back to you tomorrow. Have responded to Floyd though if you'd like to check.

Cheers Drew
 

Drewsifa

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Apr 8, 2021
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Get a icharger x12, or icharger 4010duo each can test/charge 9s batteries , yes you can make a powerwall with them. but sooner or later you would have to break the packs up. Many inverters are based on lead acid batteries 12v, 24v, 36v, 48v.12v is not a good fit for inr cells, 24v(7s) is better, 36v (10s) ok not too many inverters for 36v, 48v (14s) is best. If I understand right you have 250 9s2p batteries 4500 18650's 14s300p could potentially yield 21kWh
if my math is right.

Later floyd
Thanks again for reply. Been really bizzy but got a chance to look at chargers you suggested. They are quite expensive is there a cheaper option? I'm quite happy to diy something if need be.
Cheers Drew
 

italianuser

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Feb 25, 2020
Messages
148
I'm no powerwall guru (yet:)), you could buy more than one smaller units and just line them up on your desk. It's does make sense doing a consistent test on all cells using devices from the same brand.
 

floydR

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Thanks again for reply. Been really bizzy but got a chance to look at chargers you suggested. They are quite expensive is there a cheaper option? I'm quite happy to diy something if need be.
Yes the icharger 4010duo is quite expensive ,the x12 is about half the cost of a 4010duo still expensive. I am not sure if there is a diy solution out there. The best(cost effective) way to go about this is to break the packs down into individual cells, test with any of the 4 slot testers (1 brand)/ get a MegaCellCharger/there are several diy solutions for 16+ cells testing.There might even be a DIY tester than will test 9s packs. and will give as much info about the cells as the ichargers.
Later floyd
 

Drewsifa

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Apr 8, 2021
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Yes the icharger 4010duo is quite expensive ,the x12 is about half the cost of a 4010duo still expensive. I am not sure if there is a diy solution out there. The best(cost effective) way to go about this is to break the packs down into individual cells, test with any of the 4 slot testers (1 brand)/ get a MegaCellCharger/there are several diy solutions for 16+ cells testing.There might even be a DIY tester than will test 9s packs. and will give as much info about the cells as the ichargers.
Later floyd
Thanks again. Thinking about breaking a couple for testing for now. As these are supposed to be brand new cells from discontinued line, i think a random sample, just to make sure should be fine. I have hardly had time to even think about which way I'm going with these yet. I may even just resell these. I think I could probably make a decent profit, maybe even more if i break them down? Then reinvest to try get more energy dense cells. I did quite well from first 20 laptop battery's I harvested. But what is better, new cells with less mAh or second hand with more mAh. Also still trying to get my head around the C rating, how much should I worry about this. The samsung cell are apparently 18C.
cheers Drew
 

Drewsifa

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Apr 8, 2021
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I'm no powerwall guru (yet:)), you could buy more than one smaller units and just line them up on your desk. It's does make sense doing a consistent test on all cells using devices from the same brand.
Hi Mate. Can you do this without breaking up the pack?
Cheers Drew
 

italianuser

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Feb 25, 2020
Messages
148
Uhm, consider that you have a 9S module... somebody else could have a 10S or maybe a 7S. That's why you wont find a universal tester. Without breaking the pack I don't know any commercial devices to make a test.

I was giving for granted you would work with single cells (or at the most with two parallel cells)! :giggle: With single cells you obviously have the maximum flexibility to make any pack you like, choosing voltage, how many in parallel and most important for me sizing (I need a long and slim pack and not a square pack, because of space limitations I have; I'll make it 10cells x 28). This is my drawing to choose the right size for me, I'm going for the schema on the right 2x7 for 70x16cm, each battery holder (the black dot!) is a 5x4 cell holder, mounted with the long side horizontaly:

14S20P.jpg

[THINKING_MODE_ON] Maybe it's possible to simply use a 9S BMS and a charger and read the measurements BMS gives you. But what if you find a weak cell? You must break the pack anyway[THINKING_MODE_OFF] LOL
 
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