Let's not overlook the fact that automotive battery charging systems are a LOT more simplistic that the average battery charger. The automotive system NEVER tapers the charge as the battery reaches a FULL SOC. It can't, the SOC of battery that's being "charged" cannot be sensed due to varying electrical loads in parallel. So a compromise MAXIMUM "charging" voltage is used as the target alternator/VR voltage output,
That results in a maximum SOC of the chassis battery being only 60-70%
Only a charger that operates with no parallel loads can sense a battery's TRUE SOC.
