Thrillhouse

A co worker is working on a 211 with a battery light and consumer light on, it has no draw, no codes, just had the regulator campaign, bcm campaign done. passed midtronics, had a second regulator put in and it worked for 3 days until it started again, have good continuity between alternator and starter and at the regulator itself, has good ground, bcm has good ground, all actual values look good, alternator is charging at 100+ amps under load with a vat40 test, I have been helping him with it, along with a few others, I think this car was forged in hell, any help or experience would be appreciated

MBTech21

What exactly does the battery message say? They are all different messages that point to the problem. If it's in consumer shut-down, that means the voltage is too low (or high)at the main battery (or it thinks it is). 100 amps means nothing if the voltage is too low(or high). I would re-check both batteries- actually, I would try new ones to see if it changes- load testing gell packs is a bad idea, seen lots of them destroyed like that.
The system is looking at voltage differential, so if one battery is being charged at 16V and the other at 13.5- it senses a problem and shutdown occurs- it assumes that it is low on voltage, when in reality, the voltage is too high and the 16V battery is to blame.

Thrillhouse

so if they are charging at different rates, then the bcm is not doing its job?

MBTech21

Maybe, but more likely it is the battery- old school teaching here - if voltage goes over 15.5 while on a charger- battery is no good. Same principle when the car is charging itself.