Dual Battery

Does anyone have a dual battery setup? If so, how much was it and what type? Im thinking of setting up an extra battery (or maybe even just 1 bigger/better battery so i can run one of those portable coolers in my car, so i can have a cold drink at work, or a semi-portable fridge when i go camping/partying.

It works off a 12v supply but ill have to see what kind of drain it makes first...
Suggestions?

12volts, 50watts and 3.8amps...

Your only realistic option is a split charge system and a lesiure type battery of around 50Ah or more..

Hmmm. Looks interesting :) Thanks.
Found this page on split systems,
http://www.kampenwagen.co.uk/Split%20Charge.htm

Ill fish around a bit more before deciding on the whole 2 battery system, or even something that kills the fridge/cooler once the battery goes down to a certain level.

Buy a small good insulated esky chuck in couple of those freezer bricks and will last all day no worries.
Nothing to go wrong and cost you next to nothing.
Advice from an old fashioned man.

Thats the other thing i was thinking :D

Do they make low-circular eskys???
Like say, the size of a spare wheel? :D

Reckon you could make your own to an exact fit you wanted.
Innner and outer frame even made from ply or thin bendy alloy and then fill in between using those foam aerosol fillers.
Timber is a very good insulating material ( use marine ply)
a nice coat of varnish and would look smick.
I can remember old cold rooms made from timber and charcoal used as the insulating material. They were just as efficent as modern ones.
Get creative!!