48V 12Ah battery RED/GREEN light blinking

[pmmali]

I am doing Electric bike repair and we are fixing GEL or lead acid batteries to the Electric bikes. recently our customers are interested in Lithium-ion batteries and many customers bring Lithium-ion battery packs (48V 20Ah, 36V 12Ah) to repair if any battery becomes fat or any acid leak I can identify and replace it but most of the time all batteries look like new.
in this case, how can I identify which battery is exactly damaged ( coz all look like new.)

and it is necessary to charge each and every battery and balance the battery voltage equally before assembling the pack. if yes then pls tell me how can I balance the voltage on all the batteries at one time.

I really love to assemble and repair batteries and I am looking for advice and replies from any experienced guys.

Regards.

 

[Diggs]

This forum focuses primarily on ebikes. Your question my be better asked at a forum for batteries like "Second Life".

https://secondlifestorage.com/index.php

 

[amberwolf]

Their question is *about* ebikes (troubleshooting and repairing their batteries, specifically), and there is plenty of info here on this, should they choose to read it.

This forum focuses primarily on ebikes. Your question my be better asked at a forum for batteries like "Second Life".

There are a LOT of battery troubleshooting, repair, and building threads here on the forum, especially in this subsection.
https://endless-sphere.com/forums/viewforum.php?f=14
and these
https://endless-sphere.com/forums/viewforum.php?f=2
https://endless-sphere.com/forums/viewforum.php?f=49


I highly recommend reading thru as many as you can find to get the existing advice and procedures for testing, as these are essentially the same for any battery regardless of cell type or construction.

If after you have read these, you then post pictures and as many specification details and a complete problem description of the specific pack(s) you need to repair, including any and all measurements or tests already performed, espeically that based on reading the existing threads, we can offer more specific advice.



Note that if you don't reply to this thread with those details, we won't be able to help you very well, and you'll be on your own learning how to do what you want to do.

I am doing Electric bike repair and we are fixing GEL or lead acid batteries to the Electric bikes. recently our customers are interested in Lithium-ion batteries and many customers bring Lithium-ion battery packs (48V 20Ah, 36V 12Ah) to repair if any battery becomes fat or any acid leak I can identify and replace it but most of the time all batteries look like new.
in this case, how can I identify which battery is exactly damaged ( coz all look like new.)

and it is necessary to charge each and every battery and balance the battery voltage equally before assembling the pack. if yes then pls tell me how can I balance the voltage on all the batteries at one time.

I really love to assemble and repair batteries and I am looking for advice and replies from any experienced guys.

 

[pmmali]

@Amberwolf

Thank you Very much for your detailed Reply.

Regards.

 

[pmmali]

Hi recently I received 4 battery packs for repair all are the same brand and same Voltage 48V 12Ah.

once I open I found some cells were fully not working. and I have replaced and checked the total voltage it shows fully 48V but when I try to charge it with charging LED quickly become red to green and blinking red and green frequently. all 4 packs work the same as this. kindly help me to solve this. what should be the problem,

[youtube]p2k8mb5LTy8[/youtube]

 

[eMark]

... but most of the time all batteries look like new. ... in this case, how can I identify which battery is exactly damaged ( coz all look like new.)

You first need to trouble-shoot to determine if problem is more likely a faulty BMS or a failed parallel group of cells or both. Ideally need to test the voltage of each cell in parallel group. It's very labor intensive to remove and replace one or more weak/bad cells in a spot-welded pack. Are you skilled in spot-welding repair?

Doubt it's worth your time to try to repair a used 36V or 48V lithium-ion battery pack. There's no guarantee how long your time consuming---labor intensive repair will last. Trouble-shooting and repairing a used Lion battery pack is too time consuming for you to make any money (IMO). The customer wouldn't want to pay what you would need to charge just for your initial diagnostic labor charge to determine extent of damage. More likely than not they'd decide repair cost is too expensive (with no guaranty).

Repairing a Lion battery for yourself as a learning experience is one thing, but attempting to repair for someone else is quite another matter. Even if a customer has an idea how much is involved (i.e. basic diagnostic charge with repair cost uncertain), they wouldn't want to pay what you'd need to charge to cover your repair costs.

Chances are the typical Lion battery brought to you in need of repair is a cheapy Chinese battery purchased from Aliexpress or Alibaba that most likely is not worth repairing.

One solution is to suggest they upgrade to a replacement from Unit Pack Power ... shipping to Sri Lanka can't cost anymore than AliExpress shipping charge ... https://www.uppbattery.com/collections/ship-from-china-530

 

[999zip999]

Look up DIY lithium battery book.

 

[eMark]

You first need to trouble-shoot to determine if problem is more likely a faulty BMS or a failed parallel group of cells or both. You need to test the voltage of each parallel group

This should get you started by first doing a basic diagnostic test ... https://www.youtube.com/watch?v=0GmEmdP1WZY
(finally an instructional youtube with some pleasant background music) ...

Here's another showing what's all involved in a BMS diagnostic/repair ... https://www.youtube.com/watch?v=wJyFALSY9Dk

 

[pmmali]

... but most of the time all batteries look like new. ... in this case, how can I identify which battery is exactly damaged ( coz all look like new.)

You first need to trouble-shoot to determine if problem is more likely a faulty BMS or a failed parallel group of cells or both. Ideally need to test the voltage of each cell in parallel group. It's very labor intensive to remove and replace one or more weak/bad cells in a spot-welded pack. Are you skilled in spot-welding repair?

Doubt it's worth your time to try to repair a used 36V or 48V lithium-ion battery pack. There's no guarantee how long your time consuming---labor intensive repair will last. Trouble-shooting and repairing a used Lion battery pack is too time consuming for you to make any money (IMO). The customer wouldn't want to pay what you would need to charge just for your initial diagnostic labor charge to determine extent of damage. More likely than not they'd decide repair cost is too expensive (with no guaranty).

Repairing a Lion battery for yourself as a learning experience is one thing, but attempting to repair for someone else is quite another matter. Even if a customer has an idea how much is involved (i.e. basic diagnostic charge with repair cost uncertain), they wouldn't want to pay what you'd need to charge to cover your repair costs.

Chances are the typical Lion battery brought to you in need of repair is a cheapy Chinese battery purchased from Aliexpress or Alibaba that most likely is not worth repairing.

One solution is to suggest they upgrade to a replacement from Unit Pack Power ... shipping to Sri Lanka can't cost anymore than AliExpress shipping charge ... https://www.uppbattery.com/collections/ship-from-china-530

Hi Thanks for your advice. yes i am experience in Spot welding. our main problem is in our country right now we cannot import any vehicle! and any kind of battery!!
So people are try to fix the old stuff and use it. we dont have any other option right now. this is the only reason to repair old batteries. and Aliexperss or Alibaba, amazon they dont ship batteries to our country.

 

[docw009]

Your location says Sri Lanka? Then hello to Sri Lanka!

E-marks has given you some good places to start learning. Ask questions to learn more.

I'll add to the discussion by suggesting these measurements. It will tell a lot about battery.

Take the total voltage across the battery. Take the individual voltages across all 13 series groups. You should see how each cell group flips in polarity.

Be careful and don't let anything short circuit. Lot of power in even a nonworing battery,