dual battery

Hi Brian R,
I have just fitted a Derek Bester battery management system in our 79 series cruiser, no room in engine bay for aux. battery, mounted it in the aluminium canopy, ran a heavy battery cable back to the isolator in the engine bay, flick a switch on the battery monitor in the cab to bring aux battery on line as a starting battery.
From+ junction block under the canopy run a + cable to the rear of the vehicle for a caravan battery top up.
Brilliant system from Derek, $160.00 plus postage.Check out his web site for extra wiring diagrams.
A very satisfied return customer from the great state, WA
Ken

Hi Brian.
I installed a DBI 120 from Derek to power the second battery. Works well & excellent service from Derek.
Cheers.
Vince

Brian,

You know the old saying, "you get what you pay for"?

A couple of replies have mentioned an isolator solution from Derek Bester of Sidewinder fame. Whilst this may be OK, you still need to locate and secure a second battery somewhere.

Derek also has a much better solution on his web site in the form of a Sidewinder Flyer.
This intelligent box includes a built-in isolator to control the operation of dual batteries, whilst still being able to charge them.
You just add an AGM battery of your choice (I use a 100Ah Remco) and the kit includes the appropriate size charging cable and circuit protection.

The Flyer has three 12v outlets. One Hella style outlet is suitable to connect your fridge to and another Anderson connector outlet, is ideal to connect up the van cable to, should you need to charge any batteries that may be in the van. This is achieved via a patch lead also available from Sidewinder.

Sidewinder Flyer

Brian,

Presumably your fridge in your new van will be a 3-way. If so, your fridge will draw somewhere around 10-15 amps when in 12V. You should run your 6 B&S all the way back to a distribution point in the van. The wiring from your caravan fridge to the distribution point should be as heavy as reasonably possible (8B&S, perhaps). Same for the negative from the fridge!

It's not quite so critical for a compressor fridge as they draw much less current.

Also, if you intend to charge a battery in the van, particularly if it's a deep cycle, while driving then you probably need a dc-dc charger in the van, especially if the fridge is pulling the voltage at the end of the 6 B&S line down.

Cheers