second battery

I'll leave those 'in the electro-know' re the best battery type, but keep in mind that if it is going in the engine bay, some deep cycle makers class their warranty as void if you put it in that very hot environment....the case can bulge !

Is it going under the bonnet or in the cabin somewhere.

A starting battery is all that is needed

Fit another identical to the first.

Then you can swap them around if one goes belly up. As we did and we didn't replace the broken one until we got home. The corrugations shook the plates loose on it.

Amusing though because until it twigged. Every time we slowed or stopped we would look at each other and blame the other for the stink. Had to laugh though. Five minutes stop and we were away.

But then again we have three Allrounders under the bonnet because we sometimes like to camp for a bit every now and then and don't carry generators or solar cells. The two fridges work fine with no charging for up to three nights.

kamn1
As the second battery is going under the bonnet, and is going to be running a fridge, then the only choice is a flooded deep cycle as these are the only type of battery that will withstand both the heat AND the cycling that is required for the fridge and survive. It can also be used as a starting battery if the need arises.

Starting batteries will not survive with continuous deep cycle applications, and some will not operate your fridge for more than a couple of hours (if that) as they are designed to give that BIG INSTANT current flow that is required for starting purposes, not the slow continuous current flow that a fridge application requires.

Hope this helps.
Regards
Athol

I would suggest you use a marine pro as it has some deep cycle ability, should handle corrugations reasonable well and IMO is very good value for money.

Another Option would be an Optima but they are expensive for the money.

Other deep cycles that will tolerate under bonnet temperatures are around but you'll have to do some research.

One thing to keep in mind if your going to use a VSR setup is that a lot of deep cycles don't like high charge rates so again do some research before buying.

Hi kman, I installed an 80amp deep cycle battery under the bonnet of my 120 and it is working perfectly after about 25,000k. It is hooked to a redarc solenoid to protect the crank battery. Will run 38litre engel for about 30-40 hours. Hope that helps

Hi Paul
The Auto sparky does not know what he is talking about
I fthe batterries are both the sameTYPE Ie floooded wet cell batterries there is no problem with charging them both aFlooded wet cell LA starter & aFlooded wet cell LA deep cycle at the same time
In fact that is the way most are set up
What iisimportant is to have goos connections a heavy cable to the 2nd batterry
Also to protect the crank battery from discharging when the engine is not running & the fridge is, you should fit EITHER a VSR or an igntion contolled relay in the pos line to the 2nd battery
The size of the 2nd battery will need to be considered
That will depend on how long you hope for the fridge to run without the battery needing to be fuly recharged
Two question:
What TYPE of battery is the crank battery ?
Do you know what peak voltage the alternator charges to?


PeterQ

Hi Kman1,

I think I heard somewhere that the later Prado's have a Smart Charge alternator, if so you may need a DC/DC charger to get the most out of your system and keep your auxillary battery charged fully.
Although I may be wrong. lol