Best deep cycle ?

mena661 wrote:
Why would you need a car jar battery when tent camping?

Well ... that depends upon whether or not you wanted to be comfortable on cold nights in your tent without being all gussied up in a sleeping bag.

Using a 100 AH "car jar battery" one could easily have one of these inside the tent to safely and quietly keep the chill out all night long (assuming the liquid acid car jar battery was left outside the tent):

http://dealspl.us/sharper_image_worlds_smallest_big_heater_81097

We have two of these little wonders. They'll run off a small inverter and are two speed - 150 watts (12 amps at 12 volts) on HIGH, and about 75 watts (a little over 6 amps at 12 volts) on LOW. They're very efficient at conversion of electricity into heat, too - as their case does not warm up at all when they're heating. All of their heat comes directly and only right out of their little adjustable front grill.

P.S. Of course when I sleep in the cab of our 4X4 truck when out and about, I power one of these with a special (no longer available) 90 AH yellow-top Optima AGM battery so the battery can safely be used right in the truck's cab to keep the battery warm for maximum battery life. In a tent, one would want to power the heater with an AGM battery, too, so that the battery could be right in the tent with you keeping itself warm.