Hi I need to add a 2nd auxillary battery to my 83 Watercooled westfalia camper. I will be using it primarily to run my laptop and maybe a light.
I understand that the battery will fit under the driver's seat. I ordered an aux. battery kit from gowesty but I have a few questions.
If I have two batteries do I need an Isolator?
Here's someone saying I do. "A dual-battery-relay is a simple switch, disconnecting the two batteries, when the engine is turned off. But the moment the relay reconnects the batteries, the drained battery robs power from the starting battery. This sudden transfer of current from one battery to another can damage batteries, and shorten their life.
A solenoid will disconnect batteries form one another, but the second the solenoid reconnects the batteries there is a sudden discharge from the main battery to the aux. This shortens battery life and can leave you with two dead batteries or worse - a fire."
I want to charge the auxiliary battery when the engine is runnig. I don't want the auxiliary battery to rob current from the main battery as described above.
Do I have to have both batteries connected to each other? Why don't I just connect the auxiliary directly to wherever the main battery gets its source from.?
I'm looking for the best, simplest and most inexpensive solution. Any ideas?
How do I hook up some sort of voltage indicator so I can see what kind of charge the aux is holding?
I have looked at the solution at vanagon.com but need more info.
Thank