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Bafang 5P Smart Charger and BMS

Old 08-18-19, 09:14 AM
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TonyVov
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Bafang 5P Smart Charger and BMS

I am struggling with a battery that died after several months of no use.

Need some advice to select a new bms board.

I suspect it is over discharged. The observed symptom is that battery charger shows charge complete as does the led lights on the battery when the 43V battery has only 21V.

I cannot buy replacement battery in Indonesia so am breaking into the battery.
Ali the cells have about 1.6v

Battery is Bafang BT C01.450.UART
3.63V x 12s x 4p = 450wh and 43V

I am in the process of charging each cell with a small single cell 18650 charger,
I have opened the pack and removed the bms and charging through the bms wires.
Currently half way through and so far all cells seem to take the charge. So I suspect the BMS is bad.

There are hundreds of BMS options available options on line.
I know I need 12s, 43V 20A capability.
The question is how can I know if the BMS will talk to my Bafang smart charger 5p and manage the charger for bulk and balance charging?
I think it is something to do with the UART communication but am not sure I understand this part of the selection

Can someone hold my hand or guide me on bms selection and help me as I troubleshoot this battery battery??
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Old 08-19-19, 09:46 PM
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TonyVov
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Fixed?? Bafang Battery Troubleshooting

I think I got it kick started, the system seems overly complicated and the documentation and feedback support from mfr is very poor basically nonexistent.
If Bafang want to service the diy market they need to make some info available.


The product looks like it is good quality, mosfet Toshiba battery 2600ma 12sx4p 3.73v nominal and bms has 40A hand written on it for a 20a Max discharge rate battery pack.

How did I 'fix' it?

Open the pack
Disconnect bms.
Measure each 4p cell at 1.6v(cell minimum in spec is 2.75v)
Charge each 4p cell to 3.6v for the 12 series cells through bms cabling. This took 3 days.

Reconnect Bafang 5p smart charger and bms, voila, I get a red light and it seems to be back to life with 2 bars on battery LED indicator
This BMS has sleep and deep sleep modes but I am guessing I went beyond that point?

If I had an external power supply I could have avoided a lot of breaking things apart and just bulk charged from b+ and b- monitoring bms voltages manually.

I am praying that I have a rejuvenated pack. There is quite some cosmetic damage to this pack now, time to get some mylar and shrink wrap and a few new screws.
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