B2B Advice

You'll have to provide a bit more info. B2B is usually installed in conjunction with a Lithium battery set-up.

It might help if you say what your conversion, model and year of manufacture is.

In every conventional set up I’ve come across, both batteries charge on hookup but some need manual switching from one to the other.

I I think we need a bit more detail of the conversion in question, It very much depends on the set up. In most circumstances whilst the engine is running it will charge both cab and leisure batteries. From then on it becomes more complicated. The electrical system in the van, when on 230v mains should charge the leisure battery and provide 12v supply within the van via a transformer built into the system, but cab battery charging via this system is far from universal. From what you say you don't have this sort of system. If that is the case perhaps you need to consider a solar panel if you wish to spend time off grid?

David

Simple to check, if you have a meter. Put it across the leisure battery when you park up, note the voltage. Connect to the EHU and again check the voltage and if it is higher than the first reading, then it is charging - it should read around 13.8v, or higher when on charge.