Bus precharge using PCFET pin does not work as intended

[martinjaeger]

The idea was to use the pin originally intended for slow charging of a deep-discharged battery to slowly charge bus capacitors and prevent high discharge current through the FETs during turn-on.

This does not work as intended, as the gate of Q14 is kept at the top cell voltage and thus allows continuous discharge current through the precharge resistors if EXT+ is pulled low.

Workaround (not using the bus precharge anymore) is to remove Q14.