2011 D22 Battery Setup

Hey Guys,

I know a bit of this is already mentioned, but if anyone can shed some light for a real simple person like me then thanks.

So, I've got a camper trailer and about to wire that up with a 12v system, and the deep cycle will be mounted in the camper.

What I wanted to know is, can you setup an isolator (like projecta 100amp) in the nav and that will perform that task of keeping the campers battery and both batteries in the nav up to scratch?

Thanks guys.

The other thing is where do you postion the isolator to make what I've mentioned effective.

The trouble with the battery in the trailer is the tyranny of distance. Over that much cable length there's so much voltage drop it becomes useless. An isolator at best provides whatever your alternator puts out, and your alternator is designed to charge the battery right nearby - voltage drop is negligible and therefore the battery receives a decent (about 75%) charge.

By suffering even half a volt drop over that distance you take the charge from 14.4V to 13.9V, which will not supply the trailer's battery with enough power to charge at all. You need to clear 13.8V by a decent margin - 14.4 up to 14.7V is a good place to sit to charge the battery at a decent rate.

The best way (by far) is to use a decent cable to the rear and run that into an inverter. The inverter's circuit will use as little as 11.4V (some will continue working down to about 10.75V) to produce decent 240V and from that you can run any charger you like (within capacity limits, of course). This will allow your trailer battery to charge beyond the 75% that your vehicle battery charges - giving you even more capacity while camping.

All you need to do in the engine bay is add a 30A thermal reset fuse and a relay that turns this cable on only when the ignition is on. Use decent gauge cable to the rear, a minimum of 6 sq mm cable (both positive and negative) is good, 8 sq mm is best.

That should give you trouble-free power. And yes, it's how I do it in my caravan, AND in my tub.

Projecta 100 actually states that the longest distance between the main battery and the isolator is 5.5m (cable not straight line) so keep it under that with the cable supplied and you'll be fine. My old man's crewman had the Projecta in the tub with 3.6ish meters of cable and it ran fine.

Given the D22 has more room under the bonnet I'm sure you'll find somewhere to mount it but if you wanted it in the tub and you can't run a straight (or almost straight) line with the cable just bare in mine Projecta only limitation which is the 5.5m from the battery.