Running cables to back of car from 2nd battery

[MYT150 Member Find all posts View Profile Close MYT150]

404pug,

It is recommended to have the brake controller and the driving lights connected to the main battery, as bot should only require power when the car is actually running. General rule of thumb is to put anything that only requires power only when the car is running goes on the main battery and anything that needs power when the car is off goes on the second battery.

[404pug Avid PP Poster! Find all posts View Profile Close 404pug]

I can see that re. the electric brakes which are used very rarely but I thought that having the driving lights which are used regularly might be better at the 2nd battery so that it has to provide some power to something sometimes?

[MYT150 Member Find all posts View Profile Close MYT150]

Unless you are doing a lot of night driving in the country you won't really use driving lights a lot, at least that is from my experience. And generally if you are you will probably be running a fridge or something else of the battery at the time. Also if you do have a problem with the second battery and you want to drive at night then you won't have your lights, compared to if they are on the main battery. Yes if you have issues with the main battery you won't have the lights either but you probably won't be able to drive for long either.

[dBC Member Find all posts View Profile Close dBC]

I can see that re. the electric brakes which are used very rarely but I thought that having the driving lights which are used regularly might be better at the 2nd battery so that it has to provide some power to something sometimes?

Do you use them with the engine off? Assuming not, then if you're a VSR kinda' guy both batteries and the alternator are all connected via the VSR and it's the alternator that's running the driving lights so it makes little difference (although you'd be increasing the length of wire between the alternator and the lights, and potential points of failure as MYT150 says). If you're a DCDC charger kinda' guy then your driving lights would be eating into your limited (20A, 25A etc) charging current so would make your aux battery charging even slower.

[404pug Avid PP Poster! Find all posts View Profile Close 404pug]

Using a VSR