redbeardbeer said:
Voltage between Charge- and pack+ is around 5V
Voltage between B- and pack+ is 52.6V
Votlage between P- and the pack is 5V
Well, that does indicate the BMS has turned off the ports, for whatever reason.
BTW, if you have 4.0v on every cell, a 13s battery does add up to 52v that you read across (presumably) the actual main battery (cell) wires.
But if you read 52.6v somewhere, that should be impossible with only 52v--there's nowhere for the 0.6v to come from. :?
When I connect the charger I get:
P- to Pack+ is 26V
Charge- to Pack+ is 54V
What is B- to Pack+ in that event?
If it stays at 52v, it means the BMS is not enabling the charge port either.
If it goes to 54V (presumably the charger's actual voltage output), then it is enabling the charge port at least while the charger is connected.
If the BMS has actually failed:
A BMS is an electronic device, so it is possible for it to be damaged by ESD (static electricity), and that can happen during any handling of it (including the factory and any sellers between there and you). This happens more often on small-voltage inputs (like BMS sense inputs, or on IC chips on the board).
It is also possible that depending on it's design, an incorrect sequence of connection or disconnection of it's leads could cause voltages across components that they can't tolerate, leading to their damage or failure, which can cause the BMS to not respond correctly to within-limits readings (because it can't read the cells correctly, or doesn't respond correctly to them, etc).
Unfortunately neither problem is usually repairable as parts to do so aren't typically available. (or else the markings on them were removed so you can't tell which ones to replace them with).