Cockpit freezer?

I've got a nice fridge/freezer on the cockpit that I store beer and drinks in. It's got a AC based compressor and I believe it's just cold plates that are inside it (but not visible). There's an electronic temp control and a thermostat in the bottom, as well as a drain.

There is no seal around the top. There's a clear plexi board that fits inside to help seal but I've been told by many people that I should seal this and it will use much less power. The previous owner warned me against it due to condensation problems.

I tried sealing it and the PO was right. I had iced the sides inside 10 days pretty significantly and had to empty and defrost.

Somebody asked if the unit had a defrost mode, which I don't believe it does. I'm wondering if I could replace the controller with one that does have a defrost mode? I was told some can reverse the cold and heat the plates to quickly defrost. I've no real idea if this is possible, or what I may need to do. Changing the plates would be a big job, so I'd like to stop short of that.

As always, any advice is appreciated!

Actually, it's fine with no gasket at all - it's when I put a gasket in that the freezing happens.

I'm not trying to make it frost free, but to minimize if possible. I was even thinking of putting a timer on it. Maybe have it shutoff at midnight until 8am. By the time I want a beer the next afternoon, it will have had lots of time to chill back down. The thought was that any frost might melt and drain during that "off" time.