by daveesl77 » Wed Dec 09, 2015 9:51 am
We put a cheap Haier 3.3 ft3 dorm fridge on the inside of Conch Fritter. It runs off of a cheap Centech 2000 watt inverter. We love it! When we did our initial tests on it, outside temp was in the mid 80s. I have an old truck battery (not a deep cycle) and a 50 watt Renogy solar panel, along with 120v shore power. With the test, it was a sunny day, fridge was not precooled. Had fully charged the battery the day before. Started the test at 8am, turned fridge on plugged into the inverter using battery only. Around 9am attached the solar panel, but did not align as the area was still in the shade. Around 10 am was able to align panel to sun. The fridge had been set on max, to make maximum draw on system. I have a wireless temperature sensor that I put inside the fridge to monitor the temp as I drive. Fridge (empty) came down to 16F. Every few hours I would open the door for about 10 seconds, just to keep it working hard. After 11 hours of use like that, with the sun down so no solar energy at all, I finally pulled the plug on the experiment as the battery voltage finally dropped down to 12v =/- 0.1v. But the fridge and inverter were still going strong.
When we travel, we have the charging circuit from our truck to the camper, and we have found it best to run the fridge at about 30-40%. The compressor, at this setting, once cooled and not being opened, only runs about 12 minutes per hour. Presently I have to manually unplug from the inverter and plug into shore power (if available) when we camp. This winter I'll be adding in an automatic switching system using some 40 amp, dual pole, digital relays I have laying around, so it will change by itself. I keep the interior temp at about 28F and this is running during times in the mid 90s.
I was able to run it overnight, completely off of an overcharge on the battery, 75F outside temp, not opening. Interior temp stayed around 35f. So, when I change over from the crappy old truck battery to a serious #27 or so I feel pretty confident it will go with no problems at all for extended periods without shore power. And for those times without shore power, with overcast skies, remember, I can hit the battery with 20a from the truck and I also carry one of those little 800 watt HF generators.
And yes, we carry an ice chest, but it is primarily to hold drinks and stuff that we access frequently. We also carry an icemaker. And yes, this is a 5x10x5 teardrop.
dave