Learning about 48V chargers

Some types of chargers for the 48V BH battery show that one of its pins seem to be different than the others, and also, since this one has no connection to our BMS, it doesn't allow to charge the battery.

Measuring the voltage on it, we can see 5 V so, we have tried to connect a resistor to it that could act as a load for the charger to detect it, and then perhaps allow to enable the charge. Unfortunately, this solution didn't work.

Finally, after some struggling, we decided to open the charger and noticed that the respective wire for that connector was attached to a pad in the charger-side PCB which had "NTC" written on it. Obviously, we connected an NTC resistor right there and the result was a success.

In future developments, this NTC should be connected in the battery side. Maybe our own BMS should include it.