Wednesday, June 28, 2017
Refrigeration on the go
The veggie van has a good sized 12 volt cooler. It works well, is solidly constructed, and has plenty of room. The problem is that it's a thermoelectric cooler. Those work using a Peltier plate module that directly turns electricity into cold and heat. One side of the module gets cool and the other side gets hot. Usually there are heat sinks and a fan to dissipate the heat. The big problem with these is that they are power hogs, usually drawing around 6 amps of power. That's a lot.
It's fine when my van is running and it's plugged into the van's 12 volt circuit. Most vehicle alternators have no difficulty keeping up with the demand. The problem is that if the cooler is still drawing power when the car is off. It can kill your starting battery in a few hours.
My van has a 106 watt solar panel charging a separate 12 volt battery. If it's a sunny day the panel can just about keep up. Of course, the battery is drained when the sun goes down. The next day the panel cannot run the cooler and put much power in the battery. The cooler is well insulated so sometimes I can get away with just unplugging the cooler during the cool nights. When the sun comes up it's plugged back in. I can get away with it off-grid for a few days, but by then the battery is getting low. Heaven help you if it's cloudy or your solar panel is shaded by trees.
They do make more efficient coolers that are actually mini refrigerators with small low energy drawing compressors. Not only do they use a lot less energy, they do a better job cooling and often can even be used as freezers. Thermoelectric coolers never have that capacity.
The problem is that a decent thermoelectric cooler can often be had for around $100. Even entry level compressor types are at least 4 or 5 times that price. That's the only thing keeping me from changing over. Even with the price difference, I'm very tempted to upgrade to a compressor type. Much depends on how primitive we decide to camp this coming winter. If we stay at a campground with electricity, it's easy to use a 120 AC to 12 DC converter.
The best part of having an electric cooler is not having to deal with ice. It didn't take me long to get sick of having to always hunt down expensive ice that melted and made my food soggy. If I want to deal with ice I could always stay home in New Hampshire during the winter.