WinterDeere
Elite Member
I don’t follow. If the battery is so undersized that the brakes drag down the voltage, then it would not have capacity to keep the brakes locked hard, as intended.When the emergency pin is pulled that little auxillary battery is directly connected to your trailer brakes at full battery voltage voltage that in turn lowers the aux batteries voltage to a level much lower then your trucks battery so your truck is trying to charge that battery through a circuit which can't handle that much current.
If previously connected, we know the battery voltages are nearly the same. How much current do the brakes really pull?