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Can I fix and rebuild this battery? 72 volt 18 ahr  

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RJBrown21
(@rjbrown21)
Street cred = 10 mAh
Joined:3 months  ago
Posts: 3
28/02/2019 7:10 pm  

I have a spot welded triangle battery (72 v 18 ahr from calibike.com) It was overdischarged and will not take a charge. It is brand new and only used like 4 times.(Some cells went bad). I want to know if I can, 1.) disassemble it completely. 2.) Find the bad cells 3.) Revive them or replace them? 4.) And finally reassemble it with a vruzend kit.

Let me if you can help. Also Id need to know if the vruzend battery packs are too large for my ebike frame. How would I make a custom shape with the vruzend kit? 


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RJBrown21
(@rjbrown21)
Street cred = 10 mAh
Joined:3 months  ago
Posts: 3
28/02/2019 7:16 pm  

I can post pictures of the battery. Im not sure how to take it apart without causing a short circuit. Do I just pry open the nickel spot welds and peel it off? I just want to seperate all the cells so i can do an individual voltage reading, test for capacity, and resistance of each cell. So I can find which cells are unusable. I hope all of them aren't dead cells.


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Micah (Vruzend Rep)
(@admin)
Street cred = 5 Ah Admin
Joined:2 years  ago
Posts: 484
04/03/2019 11:43 am  

Are you sure that's the problem? Calibike batteries are known for their low quality, but it should still have a BMS that prevents it from being discharged too low...


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RJBrown21
(@rjbrown21)
Street cred = 10 mAh
Joined:3 months  ago
Posts: 3
04/03/2019 6:16 pm  

Yes Im sure its the problem. I did take the battery apart somewhat. I removed the bms for the timebeing. The +1 group of parallel cells doesnt read a voltage. Im pretty sure they are dead cells. I tried other groups and they read about 3.65 which is the lowest you can go. My buddy acfidently overdiacharges it way below 72 volts. I thought the bms shuts it down when each cell hits 3.7 or the pack reads 72? Whats the point of a bms if it doesnt ahut it down at the right time? 


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scannerguy1968
(@scannerguy1968)
Street cred = 10 mAh
Joined:2 months  ago
Posts: 2
24/03/2019 1:20 pm  

I just had the same thing happen on a Hyper Racing 2000 watt scooter 60v. Had a 12ak battery pacl with 80 batteries. I bought it last fall. Ran it a few times. Pulled the battery and stored it in the house not realizing it self drained over the winter months. Plugged it in this spring and would take a charge. I unwrapped the battery (1st time ever for a pack) and metered each cell still welded with strips and the #1 row of 5 batteries were reading zero volts. I soldered 5 panasonics in. Hooked it up and still wouldn't charge.

I then ran it until it was almost dead and the controller kicked out. Then it took a charge. Did this like ten times but could only charge to 62.1 volts vs 67.2. Opened it up and find out that a number of cells will not go above 3.8 volts. So now I ordered the v1.5 and 100 panasonics. I''m going to use this kit to make a 144 cell pack with the good batteries from that pack and the 100 panasonics. Theoretically  this should work good. Will have a 18-20ah pack with 9 parallel and 16s.

Also plan on putting a video up on my channel of the build. Fingers crossed.


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