I first like to apologise for my terrible English so please bear with me
I'm experiencing a BMS issue which is causing my battery to charge incorrectly. I have two aftermarket amplifiers installed and noticed that the battery voltage was not keeping up while the battery is as good as new. At first i thought it was a parasitic drain so I did a drain test using a multimeter. After the car went asleep the draw was 80mah which is on the high side but nothing to panic about. Alternator is also fully operational.
When using forscan i can monitor the current that goes in and out of the battery. I notice that the current draw gets higher when I do things like opening the electric windows or turning on the ventilation fans but when i turn up my sound system full blast the current drawdoes not change at all. So i think the BMS calculates the wrong SOC because it doesn’t read the extra load of the amplifiers. The battery is below 12v and according to forscan the SOC is 78%? lol? So BMS thinks the battery is 80% but in reality its mostly drained.
I read somewhere that it’s important to ground auxiliary systems not directly to the battery terminal but on the other side of the BMS Sensor like the chassis ground so the current goes through the sensor. Both my amps are grounded to the chassis. One of them is even using a factory ground. How is it possible that the BMS cannot see the extra load of my amps?
Any advice is much appreciated!
