How to wire a Manager30 from a caravan to a vehicle with a smart alternator
This information applies to the following battery management systems:
- Manager30 (BMS1230S3)
- Manager30 with RedVision Display (BMS1230S3R)
Vehicles with variable voltage alternators will need additional wiring on the caravan and the towing vehicle to overcome the variable voltage conditions and ensure optimum charging performance.
The wiring required is outlined in the diagram below;


INSTALLATION INSTRUCTIONS
VEHICLE INSTRUCTIONS
For vehicles with variable voltage alternators towing caravans, a REDARC SBI12 Smart Battery Isolator will need to be installed between the vehicle start battery and the rear 50A Anderson plug.
- Install SBI12 in the vehicle according to the SBI12 instruction manual.
- Source power from the vehicle start battery via a 50A MIDI Fuse to the SBI12.
- Wire the SBI12’s blue override wire to the vehicle ignition.
- Wire to Anderson plug at the rear of the vehicle from the SBI12's auxiliary terminal. Refer to the Manager30's manual for best wiring size.
CARAVAN INSTRUCTIONS
The Manager30 mounted in the caravan will need to be wired to connect with the SBI12 now mounted in the vehicle through the Anderson plug.
- On the green connector, bridge Pin 4 to Pin 6 by splicing the wiring together.
- In the BMS1230S3 system settings, located “set DC input trigger” and set this to ignition.
WHY DO WE DO THIS?
The SBI12 controls the power feed to the input on the Manager30. It activates when the vehicle's ignition is turned on and remains active during operation. The SBI12 deactivates when the vehicle's start battery voltage drops below 12.7V (after the ignition is switched off). The Manager30 will only initiate charging when it receives power through the SBI12.