battery black magic

I have a pair of Exide Extreme batteries and are 3 years old and still going strong.I have them in parallel to run my thirsty fridge and they don't seem to suffer much from draining them from time to time! They are made for offroad use and appear to do the job! MIchael

hi marc h1
sounds like the heat under your bonnet would fry a chicken have you considered putting an air scoop on the bonnet near where the battery is
when i turboed my mazda bravo back in 1998 my auxillary battery was that hot it was boiling and no way could i put my hand on the side of it
so i searched and found a guy in perth making bonnet scoops cost me $60 i cut a
hole and fitted it just forward of the turbo and battery so the air went in and past the turbo and took the heat down past the firewall
this cured the problem and the auxillary batterys last 4-5yrs now the mazda is 1997 model and im still driving it around and never had any more cooked batteries
cheers
barry

Some flooded wet cell deep cycle batteries, AGM’s and some other non-maintainable batteries don’t like the heat under a bonnet. The heat in the rear battery, under the bonnet location, in my V8 Troop destroyed a top quality USA made lead antimony deep cycle battery due to internal cell temperatures in excess of 60 degrees centigrade. I am having much better run out of a pair of Century N70ZZ 4WD batteries. I have disconnected the battery isolator and they are hard wired in parallel. The outlets suppling my fridges are then protected by a simple undervoltage relay. I have a voltmeter permanently connected and I keep a close watch to see that the batteries never drop below 11.5 volts.
These batteries have had a lot of use and are in thier 3rd year with no sign of dying.
When they do die I will replace them with 2 Century flooded Marine Batteries as I think they will be more suited to my type of use. AGM’s are good and I have a 5 year old Fullriver in my caravan but most AGM’s aren't warranted for the tempuratures under my bonnet.

Yes, heat will affect Gel and AGM batteries if mounted under the bonnet.

An AGM deep cycle battery is still the best choice for running a fridge, etc. and the best place for the battery is in the rear of your wagon.

Derek Bester from Sidewinder has a great solution which I employed.
For $395 you can purchase a "Flyer" which is a box to contain a battery up to 120Ah, plus the cable's, etc to connect to the starting battery. The Flyer has a built-in isolator to keep the two batteries separated from each other, but maintains the ability for charging by the vehicle alternator.
The Flyer also has a status display and a secure 12v plug to connect the fridge.

One other addition to consider is a low voltage cutout device also available from Derek. This will stop the auxiliary from being irriversably drained by the Engel as the voltage drops below a certain level.

Sidewinder Flyer
Battery Protector

Skip the Allrounder, but the Exide Extreme or a Century Overlander are good choices.

I bought a Century flooded deep cycle for mine about 6 months back (quite ok so far) - Century advise a void warranty for AGM's and Gels if you put them under the bonnet. Flooded is not as robust as the others it seems but I'm not into bush bashing or thrashing on corrugations.

Thanks for the input everyone