Dual Battery is it really needed

Dotto We also added a second fridge and third battery under the bonnet to give us a pair for all the 4WD stuff including, but not limited to, two fridges, driving lights, camp lights, charging kids toys etc etc. We can easily camp up for three days without any charging needed.

Freedom.

Phil

Actually there is no more OOOMPH, two batteries just retain the standard amount of OOOOMPH.
You only notice the lack of OOOOMPH when it isn't there.
Technically it is called cranking ability. Ability to retain and deliver battery current without excessive loss of voltage.

There has to be someone!!!!!

And to approximate with two identical batteries:

When in parallel one could say double the current.
When in series one could say double the voltage.

That can never be explained as "no more OOMPH"

Other than that does it really matter. I can just picture some of the purists, sitting on the sand dune or snow mogul beside the car when it doesn't start and playing with the mathematics of it all and after reams of calculations one says to his freezing wife "Yep one is flat!".

Phil

Not a diesel jackaroo is it?
Tim

Which one? Mine? 100 series 4.2td.

Phil

Phil

I have a second battery in my 4wd but not for starting. I have lived for five years well up in the Snowy Mountains not far below the permanent snow line. We always got the occasional two or three day period of snow each year. I never had a problem starting my car (a 2wd at that time) on its single battery.

I was working for a Government Dept. We had a mixture of diesel Troop Carriers, Coaster buses, a small Mitsubishi tip truck and a couple of 2wds. It was common to have to throw water on the windscreen to melt the ice each morning but all had the standard size single battery and all started easily.

I

Neither did I in 20 years driving with the Army. But there was always someone around that you could rely on. Even if it was just a few kms down the road.

We mainly travel solo so there isn't anyone around to help if a battery breaks, as they do in badly corrugated places. It's for insurance. I have been on enough convoy trips where someone in the group has had batteries issues. Never us.

Here is an example that you may understand.

The last time I had a flat tyre was at Oran Park in spring of 1969. Yes - no lie. And you better believe it that the girl who owned the car, now my wife, was adament that she would change the tyre, not any "bloke". And she did.

Last month we went for a solo (single car) drive along the remote and isolated Madigan Line in the Simpson. It took quite a few phone calls to get permission to do a solo drive. But we got it. We didn't see another person or vehicle between Old Andado, the Hay River Track and Poepells corner in the whole of eight days. It wasn't until well after we got back on the popular tracks that we met anyone. Get the picture - isolated and having to rely on the car, that it will get us through.

Did I leave my spare tyre at home, because I have never needed one. Not on your horses. In fact we purchased another tyre carrier for the rear, took two full spares.

That's why our car came factory standard with two batteries. Just to be on the safe (reliable) side. And we put an extra one in for the camping luxuries that like we take.

cheers

Phil

The OP said "Starcraft outback pop top with 150w solar on roof" - Would not that come with a battery. Dual batteries generally refer to a second battery in the tug.

Good, clear, easy to understand reply, many should take notice.
Regards
Ian

Good replies often the result of good information is requested and when we are not left to assume...

Nope. Don't need a second battery , fitted anyway. I carry a second smaller battery packed away for emergency ( true I have a car like motor that doesn't need a big battery ). Never had to use it. I have a 12 volt fridge and usual lighting everywhere. Done solo Anne beadell and gunbarrel. Also heaps of Simo trips with others. If I stopped for 2-3 days I'd maybe start the car for a while. Longer, get a panel.

Thanks all, it's just that we had quote for dual battery kit $199. Battery UL120 $449. Ctek DC- DC $419. And started thinking why do we need this. Yes we have battery in caravan and brand new D MAX. Safety wise could be good to have another maybe smaller and mounted under the bonnet will do.
Appreciate all replies. It's hard to get your head around everything, and planning on doing the lap next year. We also have generator.

If you have a second battery in your van there is much less/no necessity for a second one under the bonnet.

If you get stuck with a flat cranking battery you can always use your van one to get you going which is the most critical aspect of the second battery

Be mindful also of not loading unnecessary weight to your setup as it can be detrimental to you as well.

Second batteries aren't always insurance anyway. I had some colleagues doing soil survey work in the Dalrymple Shire (west of Townsville around Charters Towers) a few years ago and the corrugations killed several battery isolators. They tried all the brands, the best they could buy. Admittedly this was the mid nineties, but circuit board construction - dry joints, cracks is probably no better now. In the end they always parked the (manual Cruiser traybacks) vehicles on a slope if they could and eventually after talking to a few army mates, changed to manual switches which were only prone to memory fails.