Battery pack shuts off after a while

[bogddy]

Hello, I have a zero10x escooter equipped with a 23AH LG 14s7p 52v.

I have a problem since last year, the battery shuts off while I was driving (I didn’t have the acceleration even half way and the battery had 53v and it was not hot) and after a few minutes it shuts on and the voltage are comming back and all seems normal. I thought that the BMS would be damaged and I changed it with a completely different one (the original one had a 50Ah discharge and a separate discharge/charge port and the new one is a 60AH daly BMS with a common discharge and charge port) and the first trip with a fully charged battery I could drive about 10 km and the battery dies again. After a few days I drove it again and was able to drive 300m and died again, after few minutes all seems normal and just some meters away dies again.
First time I thought it was a bad BMS and the second option and the last is the battery cells, but how do I know which ones are bad? When I changed the BMS I measured all the battery series and nothing was wrong, no corroded or run down batteries. Cables look ok, the battery had 2 fuse for each xt60 connector and they are also ok.

I test it again yesterday with wheels in the air and all was normal, the problem appears only with my me on the escooter.

What should I do next?

I thought of opening the battery pack and taking each cell separately and then see if I have dead/bad cells, and give them a maximum charge and a discharge to see how many mAh they have. But this is a lot of work to take each one separately they are 98 cells , do you have another suggestion?
Can I test parallel cels separately? Or to one side I must to take off the nickerl strip?

 

[docw009]

"When I changed the BMS I measured all the battery series and nothing was wrong, no corroded or run down batteries."
Did you check all 14 series groups individually? When a mostly charged battery shuts off after a short distance, or when pulling high current, one group is often much lower than the rest. It shuts off the BMS when it sags under 3 volts,

You don't have to pull the battery apart, but you should measure all 14 groups, and see how far apart they are in voltages, You can disconnectthe BMS and measure at the balance connector, If you see a wide spread, see if the Daly BMS will balance it,

 

[bogddy]

I think I found already the problem after I posted this topic I found a video on youtube with similar problem like mine.

I measured today the voltage on every group of battery after it shuts off again and I found the group 6 was 3.6v and group 11 was 3.3v, the rest of battery was 3.9v.

I take a part this 2 groups and now I discharge them individually until 3v, and then I charge them to see how many mAh it takes and again I will discharge them.

I dont know If I am allowed to share the video but probably it will help others with similar problem like mine.

 

[Rocko]

Hello, I have a zero10x escooter equipped with a 23AH LG 14s7p 52v.

I have a problem since last year, the battery shuts off while I was driving (I didn’t have the acceleration even half way and the battery had 53v and it was not hot) and after a few minutes it shuts on and the voltage are comming back and all seems normal. I thought that the BMS would be damaged and I changed it with a completely different one (the original one had a 50Ah discharge and a separate discharge/charge port and the new one is a 60AH daly BMS with a common discharge and charge port) and the first trip with a fully charged battery I could drive about 10 km and the battery dies again. After a few days I drove it again and was able to drive 300m and died again, after few minutes all seems normal and just some meters away dies again.
First time I thought it was a bad BMS and the second option and the last is the battery cells, but how do I know which ones are bad? When I changed the BMS I measured all the battery series and nothing was wrong, no corroded or run down batteries. Cables look ok, the battery had 2 fuse for each xt60 connector and they are also ok.

I test it again yesterday with wheels in the air and all was normal, the problem appears only with my me on the escooter.

What should I do next?

I thought of opening the battery pack and taking each cell separately and then see if I have dead/bad cells, and give them a maximum charge and a discharge to see how many mAh they have. But this is a lot of work to take each one separately they are 98 cells , do you have another suggestion?
Can I test parallel cels separately? Or to one side I must to take off the nickerl strip?

Ya me to kinda