Twin Engine to battery isolator

Hi,

This winter sees me changing my manual start outboards to electric starts and wondered if the two engines can I use a single isolator ? thus both engines will be connected through one isolator to the start battery. There is a 100A fuse / breaker at the battery.

The second battery will serve the gps/vhf/etc.

The engines are Mariner 40’s and have a manual start option in case of battery failure.

I don't think there is a problem with the engines in general but I'm not sure how the two voltage regulators with work in parallel. One is bound to have a slightly higher output voltage than the other and this one might do all the charging. Hence you may think you've got X charging capacity but you may only have half of that.

Why not fit twin batteries and have two completely independant systems ? twin 40s will only require small batteries.

Pete

I'd be with Pete, dual isolators would give complete separation.