Hi Jas,
Here is a link to a previous post, has lots of info for you
http://myswag.org/forum/index.php?topic=5682.0 plus a "cut & paste" from a post I did on ExplorOz.com over 2 years ago. I have been running my twozone for over 2 years now and reckon it is now one of the best accessories I have. I do also have a second 40L engel as a freezer, one thing I am not short on is fridge/cripser/freezer space
...................................................................
I recently bought a Two Zone fridge top for my 40L Engels and was originally disappointed with its performance - and thats with the Two Zone insulated cover fitted.
I had the Engels running on "2" and while it was keeping my drinks perfectly cold (actually had ice in some cans), the top section was at 17C and not really keeping my fruit and vegies cold. OK - the ambient temp was 40C and both sections were fully loaded, but at ~$380 for Two Zone and cover I expected better performance. And given the Engels was nice and cold, it was the Two Zone that was not performing.
Now I figured that as hot air rises there was no way the Two Zone was going to keep cool in hot conditions as nothing was bringing up the cold air. So I bought a 12V computer fan and wired it up. Boy what a difference!!!
Running the whole setup today and I was achieving between 3.5 - 6.5C in the Two Zone as the Engels cycled on and off - and all this in a 40C parked vehicle.
Now this was really keeping everything cold and the fan only draws 0.22amps so the extra power is minimal IMHO. And I am sure a keen sparky could figure out how to only run the fan when the Engels motor is going if you wanted to further reduce the power draw.
Anyway, just thought I would share how to get the best out of a Two Zone - why they don't do this as a factory option has got me beat.
Cheers
Captain