split charge system

[Deleted member 3011]

The alternator had managed to recharge the main battery and the leisure battery in half an hour!

If that was after using the battery for 5 days, I doubt whether it would be anywhere near charged. 13.6V doesn't mean fully charged unless it first got to about 14.4V and then dropped back to float. Gel or AGM batteries are a little different, but still take a while to fully charge.

i am going down the route of a large relay and some thick wiring. over-engineering rules. i

This is unlikely to be overengineering - merely good engineering. Using smallish cable for battery interconnects or supplying a three-way fridge results in excessive voltage drop (meaning anything over 0.5V) and this seriously reduces the efficiency of the fridge and means the battery will take hours to get anywhere near fully charged - or rather as fully charged as possible with a normal alternator and normal flooded-cell batteries.

 

[Belgian]

Golden advice !

This is unlikely to be overengineering - merely good engineering. Using smallish cable for battery interconnects or supplying a three-way fridge results in excessive voltage drop (meaning anything over 0.5V) and this seriously reduces the efficiency of the fridge and means the battery will take hours to get anywhere near fully charged - or rather as fully charged as possible with a normal alternator and normal flooded-cell batteries.

This is a golden advice Tony Lee, thanks

 

[wildman]

Going of the thread slightly anyone know how a second leisure battery can be connected to the first does it need a second relay,can they be connected positive to positive?Andy

They mus be connected posative to posative or you will end up with 24V battery. additional battery must be same size i.e. both 85 amp/hr or both 120 amp/hr if you mix them, 85 plus 120 you will end up with 2 x 85. It will always charge to the lower rate and no more.