BMS can be in a charger , as i suggested above or in a battery.. or both early lithuims didnt have built in BMS.
To by pass the BMS for a battery holding a charge below any of the BMS pre sets.. can be fooled by introducing a higher voltage for a very short period... it is potentially dangerous to do so for any more than a few seconds.
If it then doesnt start to charge then something else is likely to be an issue as noted above by Salty.
Also the correct charger must be matched to the correct battery type to charge.. and correct alternator in vehicles etc.
Back in the day of std wet lead acid was never an issue.. then came geled and AGM acid batteries.. these , espec the AGM which we use ad marine batteries should not be charged on a std pb acid charger....
If you have and note a short battery life, that is why.
Cd batteries also require a dedicated charger, as do lithuim
They all charge at different rates and have different full charge voltages.
Now we have introduction of smart chargers that detect type battery, charge rates ans some even have recondition modes.
All which pretty knowledge thru hot rodding, car resto guys, marine workshops, sparkies And basic 'technicians' on cctv cameras , security, lighting and similar isolated solar powered systems etc. , and considered pretty basic stuff
I repeat if going to 'jump' the voltage to over ride a BMS either in a battery or in a charger or both, only do it for a few seconds.. no more. regardless of lithium or any other type.
Once the higher voltage is detected it then supplies its own voltage to maintain the charge sequence
All this I have posted before many times over the yrs..maybe decade.