Basic leisure battery / solar advice please

[Laz]

I just bought a used DC-DC charger and deep cycle battery (both Victron) and plan to fit a big 'ol solar panel at some point.

Ideally I'd have both batteries charging by solar. I know there are dual output charge controllers but I was wondering if I could connect a standard single output to the starter battery and let the DC-DC charger take care of the leisure battery?

[g8dhe]

Not a good idea you will loose efficiency at each conversion, why would you want to charge the SB anyway, once the ignition is off then there should be minimal load on the SB. If you really need to handle charging the SB, then you would be better off using a switching panel in the van to select which battery you want to charge and/or use for the load in the van itself. You might however need to select battery type when switching as most SB will be lead acid whilst the LB is most likely to be lithium if your using DCtoDC charging between SB to LB.

[Laz]

The starter battery is old and the Bongo isn't my only vehicle, there maybe times it won't move for a couple of weeks or more. A well charged battery is a happy battery so it makes sense to me to use any spare electricity to keep it that way.

Though, having thought about the system a bit more I suspect I'll be fitting a panel with a higher amperage than the DC-DC charger can handle anyway. I can find another solution for the starter battery if necessary.

I hadn't considered switching the supply between batteries. But as you suspect they are different types, in this case the starter is lead acid and the leisure is an AGM. I think it may be more hassle than say, a separate solar trickle charger.