Controller output vs tow vehicle output (Newbie)

[Bald camper]

When on the road, both the controller and the tow vehicle will be charging the battery, Is-that a problem.

Thanks

[Bala]

How is the charge from the tow vehicle to the trailer set up?

Options Could be, direct, igniton relay, voltage sensing relay, bcdc/dcdc.

[Bald camper]

The trailer simply connects to the truck.

The direct option, is that doing nothing.

Thanks

[Bala]

It sounds like you have the direct option. This is simply connecting the batteries in parallel. Any charge from vehicle or solar can go to both batteries, and any load is running off both batteries. When vehicle is off the solar can charge both batteries and load can come from both.

You need to check on the charge voltage of the vehicle alternator. It may have a "smart charge system" where the charge input can drop to as low as 12.0v, some Fords use this. It may have a "Temperature Compensation" system where the charge will drop once warmed up. Some Toyota systems drop to 13.2V.

Depending on the vehicle charge system the solar may be trying to charge the vehicle and you can also end up with flat vehicle battery from the trailer loads.

There are many options but,

If it is to be used often I would look at an auto disconnect type options. BCDC units have solar input and, see Redarc as an example. Their site has info on alternator types, VSRs etc etc.

If it is not used often, when travelling I would turn off the panels and remember to disconnect from the vehicle when stopped.

[Bald camper]

Thank-you Bata, good info.

Have a nice day