Yep, I saw it. Twin batteries for a Fourtrak. I removed the original battery tray, and fabricated a new one, capable of holding one main N70 size battery along the main axis of the vehicle. A second smaller auxilary battery sits across the main axis, behind the first. I used about 1 inch angle iron to construct the trays with a couple of pieces of flat across the gap. They are welded together. I used every and any possible mounting hole to mount and spread the weight. There are about 5 or 6 threaded holes that mount the original tray. I used all these, as well as running a couple of verticle straps down from the tray to line up with the inner mudguard (wing). I bolted through both. I also have a strap that hangs off the upper drivers side radiator mount bolt that also attaches to the tray. If memory serves, the tray is mounted in about 10 places. Its a bit of a squeeze, you have to make sure the battery terminals wont touch the bonnet/hood when it is closed, or when the vehicle is flexing off road. There is still room between the batteries and the upper inner wing for all original fittings, Glowplug relay, fuel primer pump/filter, power steering pump, plus this is where I run my distribution block to power all my accessories, plus relays. Alternator output is governed by a continuous duty solinoid, which is activated by a relay energised when the ignition is switched on. This simple system keeps the batteries connected when the motor is running, but disconnected when it is off.
I suppose, if I had my time over again, I would go for Oddessy batteries, instead of normal batteries. They are smaller in size, (probably both fit in the original tray) lighter, but more expensive.
The major drawback to dual batteries in the original position is, I believe, that it contributes to the infamous Rocky lean.
I have an excellent picture on file of the tray set up, I will attempt to post it in the modifications gallery.

Hope this helps
Cheers
David
Growing old is compulsary, growing up isnt, and
MUD MAKES EXCELLENT TOOTHPASTE

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