Originally Posted by
drivesafe
Hi again Gavin, and quick question, do you have the switch on the In-Cab Module set towards the LED or set away from the LED.
Under normal operation, the switch should be sent away from the LED and this allows the cranking battery to assist your auxiliary battery in supplying power for your accessories while the motor is off.
By doing this, when you start your motor, because the “cranking battery” is possibly down a bit, your D4’s BMS ( Battery Monitoring System ) will “see” that the cranking battery is not fully charged and will run the alternator at a higher voltage for a longer time.
This action rapidly charges both batteries at the same time.
If the switch is left set towards the LED, your cranking battery can be kept in a near fully charged state, most of the time, depending on your driving habits and this can mean that in a shorter driving time the BMS will determine the cranking battery is fully charged and it will lower the operating voltage more often, and why your may be seeing your SC80’s LED flashing the way it is.
Another cause of this is when you have fully charged your batteries with a battery charger and then gone for a drive. Again, because your D4’s BMS sees the cranking battery is fully charged, the BMS lowers the voltage to reduce fuel consumption.