Split Chargers

[Normanmunns]

Hi Everyone

I believe that when my motorhome engine is running, the split charger relay kicks and and puts the leisure battery and vehicle battery in parallel so that they can both be charged by the alternator.
When the ignition is turned off the relay opens so that the vehicle battery cannot go flat.
If the two batteries are therefore in parallel on start up, do they both draw current from the starter motor when the engine is fired up?

 

[tonyidle]

In general no because the split charge relay is wired to operate as soon as the alternator starts to charge either by sensing the rise in starter battery voltage or more directly by connection to the alternator warning light output.

I say in general because I have seen split charge relays operated by the ignition switch but by virtue of lengthy and usually not very thick wire to the leisure battery starter current draw has little effect on it. Not a very clever way of doing it though.

 

[Normanmunns]

Thanks for reply
You say the split charge relay operate when alternator starts to charge. but i think my relay operates as soon as ignition is on so i gues both batteries are drawing current to feed starter motor ?
I have a Autosleeper Harmony based on a Peugeot boxer

 

[mitzimad]

should only connect when the alternator is pushing out voltage sounds like yours is wired to an ignition live if you cant find a d plus signal you can fit a smartcom on to the wiring you have and use that to trigger the main relay message me if you need more info
all that is assuming you have a dumb relay rather than the vsr type