Cole-Hersee Dual Battery Isolator

So they are still automatic? eg. Fridge runs of second battery when vehicle off the when on, can run off both whilst both batteries charge?

Thanks for the info ;-)

Hi Tom,

Not all automatic. Solenoids are simple relays. You need to wire it so it is 'clever' or 'smart'.

Redarc and Sidewinder isoltors are automatic.

Regards Derek.

Thanks Derek, so by example, once it is wired up, the main start battery shouldn't ever go flat. Am I on the money or completely missinterperating this?

Thanks again,
Tom

Yes, you have the general idea.

I have had several problems with this type of system in different vehicles where a battery has slowly died but been masked by the solonoid duel batt setup. The dead battery has then theived charge off of the good one and the first you knoew there is a problem despite your duel battery system you go no - where

Hi Dave

Sounds interesting. Have you got an old one for me to look at.. (Strip down and inspect).

Isolators are Isolators, once the contacts are open they should isolate. Diode type could cause a problem as well as poorly wired accessories that can link the batteries via a globe or memory circuit.

Regards Derek.

No this was from a previos vehicle and work vehicles. The isolation wasnt the problem the problem was when a battery dies starting was still OK as the ignition kicks in the isolator so between the dieying battery and 2nd battery there is still plenty of kick to start. the dieying battery theives the charge while running from the good battery leaving you with one dead battery and one flat battery

Yes this can happen if you don't wire the solenoid to a trigger that only has power once the car is running.

If in doubt you need to invest the a 'Smart' solenoid which will only engage once the cranking battery reaches 13.4 volts. Redarc or ABR units.

Regards Derek.