Duel Batery - What Type

You will get replies with good reasons for using both types, deep cycle and cranking. Fridge and GPS etc, deep cycle is technically the one to use.
I have similar gear running off my 2nd battery, but use a cranking battery. :o) However, I run N70ZZ's as 1st and 2nd batteries, and have room under the bonnet to do it.
My reason is that I don't sit in one spot for that long without using the car, which keeps the 2nd battery topped up. And, I usually swap them over every 6 months for better battery life. Plus, I have found that I can get a N70ZZ anywhere if one fails.

If I was going to sit for more than 2 to 3 days without running the car, I would go deep cycle. You also may need a good 4 plus hours running to recharge the 2nd battery when you do charge. I need a good run of 5 to 7 hours after sitting in national parks for a few days (3 to 5) and only doing short runs to tour around.

PS - I run/recharge my laptop and GPS off my main battery while the car is running to save load on the 2nd battery. The laptop really pulls the power when on, more than a fridge.

I use an Optima Deep Cycle Yellow Top for the second battery in my DUAL..DUAL...DUAL...battery system, read about the yellow top in the above link.

Doug

Why dont you go for a marine type battery, they have both deepcycle and cranking capacities, I have one in my 3L and its been great

I"d go for a Deep cycle AGM. I have the patrol and run two 90 A/H AGM as auxiliary batteries (I run a fridge and freezer on longer trips) one of which is mounted in the rear of the car. I left the cranking battery as is. The best thing to do is ensure that your cranker is in good shape and not getting old. The AGM batteries have the advantage of being able to discharge to a greater level without damage and recharging at a greater rate also. I picked mine up for $170 each (which was a bloody great price) at Supercharge Batteries in the western suburbs (Derek from ABR put me on to them).

Cheers. Mick

Definitely a deep cycle battery.

A wet cell deep cycle is cheaper but takes longer to charge and reaching a full charge via the vehicle alternator is doubtful.

An AGM deep cycle battery is by far the better option, providing you can justify the initial cost.

Forget the advice of using a starting battery to run a fridge. They are not designed to drain down to a low level and be charged again continuously. (i.e. deep cycling)

Brand? Unimportant. Just make sure the battery footprint (size) will allow installation into the cradle.
AGM batteries have a bigger footprint than a wet cell battery.

G'day Iceman, if you want god information on all batteries and their accessories go to your local Battery World. I have no, I repeat no affiliations with them in anyway, only as a customer. The guys at Wantirna are spot on.

We use a Trojan 27TMH deep cycle in our Prado with that same controller. Have had zero issues with it to date. It is a 115AH battery at 20 hour rate and seems to be the best AH capacity battery I can find in a standard 12" case.

Cheers
Muddy

When you have done some 'home work' you will be very aware the technical differences between Cranking batteries and Deep Cycle batteries and AGM batteries.
There would not be one "qualified" 12v battery supplier that would RECOMEND using a Cranking battery over a Deep Cycle or AGM battery for camping.
Some popular Cranking batteries have a Amp Hour rating as well as their normal CCA rating, however the warranty is very often DIFFERENT when used as a cycling battery than when used as a Cranking battery, eg, the Extreme is an example of that policy.

Using an AGM Deep Cycle battery, makes even more sense and yes is more expensive too, but if you want the BEST long term PERFORMANCE then they are the best available option and anything less is just that a cheaper and less performing option.

If you are going to be continualy driving, every day or second day even a 'motorbike battery' will work, but if you want to run a fridge and spend a few days in the same place then you have to spend some money and buy a battery capable of doing what you want it to do.

AGM's charge much faster than non-agm's and they last longer and cycle more often and cycle deeper too, their only disadvantage is initial cost, however when worked out over the life of the battery it's probably less expensive to buy a quality AGM battery than a series of Cranking batteries. Remember when these cranking batteries fail it will be out in the bush, away from a replacement and when the fridge is full of Barra fillets, now that is a waste of money and time.

I picked up an AGM and a Flyer from Derek at Sidewinder http://www.sidewinder.com.au/ (also known as ABR). He even let me take advantage of the summer promotion that is out yet where I got a 100AH AGM with the flyer plus the promotional pack for around $550 plus freight. Great service, recommended.

Scott