We would like to connect the Multiplus II to the vehicle electrical system to be able to charge the “starter battery” together with additional “battery bank” when the grid AC is connected. The Multiplus II will be the inverter mode from the 12VDC alternator to the AC load while grid AC is disconnected.
The manual mentions “… product is not suitable for direct connection to a vehicle’s electrical system.”. I think it is the issue with the voltage drop at engine starting. What should we add? Are there a alternative better solution?
Youve already seperated the systems, the starter battery is connected to the vehicle and being charged by the alternator. The additional battery bank is connected to the Multiplus and being charged by the Multiplus.
Whats now missing, i suppose, is charging from the starter battery to the additional battery, by using an Orion Smart for example.
And the other way round, from the additional battery to the starter battery through the Multiplus trickle charger.
So mainly I can use the trickle charger feature of the Multiplus together with the DC/DC converter. Can I use the lower cost battery isolator instead of the Orion?
Yes, you can use a basic solenoid style isolator as long as both batteries are lead acid. If your house batteries are LFP then, technically, no. A DC-DC charger is the only reliable way to charge the LFP house batteries from the vehicle alternator. You may be able to get away with a basic isolator or a Cyrix in many cases but a quality DC-DC charger set up correctly is the best practice here. An Orion 18A is relatively inexpensive.