Spilt charge relay

[spruce]

Its not just what the alternator kicks out. I looked into it in detail. Mind blowing. If 1 battery if flat and the other full, the surge will be massive and blow the fuse. I thing small leisure batteries got away with it most of the time, But not 110amp batteries.Its best fitting as close to main battery as poss. Less chance of problems. ! fuse as near main battery as poss and one as near leisure battery as pos.

If its really close 1 fuse would be ok.

I have a transit which is a 2 battery set up/ 1 main 1 aux via ford slit charge system. then I read about modern alternators etc and put it on hold. The more I looked into it, the more complicated it got. I will just put 1 in and see what happens

The initial charging surge can be quite dramatic with just a standard system. After a big job the initial amp surge into my 110 amp battery can be as high as 22 amps (that I've seen) but very quickly drops to around 10 amps. It due to the low voltage of the leisure battery which hasn't had a chance to stabilize.

Having a higher alternator charging voltage will force that amp charge higher; that the scary side. For those who have these new vans I would feel at the moment that the only solution is an expensive battery to battery charger.