Can bypass BMS for charging and keep it for discharging?

[General_Lee]

Hi guys, I have Samsung cells 4.3v 20S8P (86V total pack) but the BMS stop the charge at 84v. If I bypass BMS for charging to rise my pack at 86v is it ok for the cells (stay balanced)? and BMS not run faulty if it see 86v, not 84v?

For sure I keep BMS when I will run my Bike (Discharging).

 

[dnmun]

what BMS are you using and what is the balancing voltage?

you should be able to find a BMS that will balance it at the 4.3V level. did you look through the BMSs offered by Bestechpower?

 

[General_Lee]

what BMS are you using and what is the balancing voltage?

you should be able to find a BMS that will balance it at the 4.3V level. did you look through the BMSs offered by Bestechpower?

I have this : http://www.bestechpower.com/74v20spcmbmspcbforli-ionli-polymerbatterypack/PCM-D131.html
for 84v ( 4.2 cells ). I know I can change it, but if I not change it? if is better to stay like this ( with BMS to charging ), I will stay 8)

I'm just currius to know it.

 

[dnmun]

did you ask henry to make the D131 with a 4.30V balancing voltage? do you know if that is actually the voltage these cells should balance to?

 

[wesnewell]

Only charging to 4.2V will extend the life of the cells considerably, so I'd leave it at that.

 

[General_Lee]

dnmum, The pack is already builded with this BMS. I not bought it separately.

Yes is true wesnewell

 

[docnjoj]

I'd just keep the present charge level. It will definitely prolong the life of your cells and you will hardly notice the extra 0.1 volt at the top of the charge. 4.2 volts should be 95% or better of a "full" charge.
otherDoc

 

[dnmun]

I'd just keep the present charge level. It will definitely prolong the life of your cells and you will hardly notice the extra 0.1 volt at the top of the charge. 4.2 volts should be 95% or better of a "full" charge.
otherDoc

but why give up 5% of storage capacity for no reason? you end up paying 5% more for the battery than you need to. then if you stop at only about 50% discharge you are using only about 45% of the available capacity for no reason.

these theories of how using the full capacity of the battery will destroy it have not been proven. it has been shown that it is not the final voltage you charge to but the length of time it spends at full charge that reduces cycle life. the professor talked about that in the lecture on the tesla user board.

i know he can buy a 20S BMS that will balance it to the voltage the cell is designed to operate at from Bestechpower. they can use the specific comparators for that balancing voltage and include different HVC and LVC setpoints too.