rebelrider.mike
Member
- Joined
- May 25, 2017
- Messages
- 554
Hey all,
I'm planning to convert a cargo trailer for camping. I want to make it semi-off-grid, and so I'll have a battery and some solar. What I'm looking into right now though is how to keep the food cold. From what I've found so far it seems that there are 120VAC mini fridges, and 12VDC thermoelectric coolers.
I'm not sure which would be better for my application.
A thermoelectric cooler would be simple enough that I could build my own for a fraction of the cost of buying one. Also, the commercial units are tiny. 1.6 CFt. They have no thermostat, so they draw about 5A as long as they're plugged in. I could build a larger one with two peltier chips, a few fans, and a thermostat. It would use about 12A, but would only run while warm inside. So it would draw 144W from the battery. An issue with thermoelectric cooling is that it's only around 30% efficient. At least that's what I've read. So the cooler would generate twice the heat outside as it dos cold on the inside. I've been playing with peltier chips, and they do indeed get cold enough to freeze condensation right out of the air, but they generate a lot of heat.
A mini fridge That runs on 120VAC might be a better setup. It looks like a very basic 4.4 CFt without a freezer uses around 1A, or 120W. I'm thinking a 500W pure sine inverter would be sufficient to run the fridge off the battery. And I could switch it to grid power whenever we're plugged in. I haven't been able to find a number as far as refrigerator efficiency, but I'm pretty sure that they are much more efficient that thermoelectrics. This would be the only AC device I'd use from the battery. So I don't want to buy a hugely expensive inverter.
So for the moment, I'm leaning towards the mini fridge. I'm guessing that the fridge would run less often than the cooler, and hopefully the peak current will be small enough for the inverter to handle. I'll continue searching and reading, but maybe you all have figured this stuff out already?
I'm planning to convert a cargo trailer for camping. I want to make it semi-off-grid, and so I'll have a battery and some solar. What I'm looking into right now though is how to keep the food cold. From what I've found so far it seems that there are 120VAC mini fridges, and 12VDC thermoelectric coolers.
I'm not sure which would be better for my application.
A thermoelectric cooler would be simple enough that I could build my own for a fraction of the cost of buying one. Also, the commercial units are tiny. 1.6 CFt. They have no thermostat, so they draw about 5A as long as they're plugged in. I could build a larger one with two peltier chips, a few fans, and a thermostat. It would use about 12A, but would only run while warm inside. So it would draw 144W from the battery. An issue with thermoelectric cooling is that it's only around 30% efficient. At least that's what I've read. So the cooler would generate twice the heat outside as it dos cold on the inside. I've been playing with peltier chips, and they do indeed get cold enough to freeze condensation right out of the air, but they generate a lot of heat.
A mini fridge That runs on 120VAC might be a better setup. It looks like a very basic 4.4 CFt without a freezer uses around 1A, or 120W. I'm thinking a 500W pure sine inverter would be sufficient to run the fridge off the battery. And I could switch it to grid power whenever we're plugged in. I haven't been able to find a number as far as refrigerator efficiency, but I'm pretty sure that they are much more efficient that thermoelectrics. This would be the only AC device I'd use from the battery. So I don't want to buy a hugely expensive inverter.
So for the moment, I'm leaning towards the mini fridge. I'm guessing that the fridge would run less often than the cooler, and hopefully the peak current will be small enough for the inverter to handle. I'll continue searching and reading, but maybe you all have figured this stuff out already?