Resi fridges in more and more units
I'm seeing more units without propane ability for the fridge. If an inverter is also supplied by the manufacturer to only run the fridge does it stay powered enough from the tow vehicle on long runs...
Forum Discussion
If you use the governments (I know I know it's just an estimate) Energy Star guide for say a Samsung 17.6 cubic foot basic 120 volt residential refrigerator, it lists the annual estimate for electrical consumption at 448 kwh per year. (very low) That means it would use 448/365 = 1.23 kwh per day. I don't care where the electricity comes from or what the duty cycle is, that's the estimate for the electricity in kwh it consumes per day.
If you have a standard set of 2 - 6 volt wet cell deep cycle batteries, they are generally rated at 232 amp-hrs @ 12 volts at the 20 hour rating. We'll be generous and say 13.2 volts for this example. As I understand it, that means that the batteries contain 232 x 13.2 = 3062 watts available in theory, maximum, until the batteries are dead from a full charge.
So, if you have 3.062 kw available in storage and you use 1.23 kw per day you will get 3.062 / 1.23 = 2.49 days of use out of the batteries before they are dead, assuming no other loads on the batteries and that your inverter is 100% efficient, which it is not. It also assumes that the batteries can produce 13.2 volts until they are dead, which, they cannot.
So, yes you can drive and keep your residential refrigerator running strong, if you drive everyday while hooked up to your alternator in the tow vehicle. It's when you stop that you will have issues. If I were guessing, I'd say you would be good for sitting around for about a day before you need to find a supplemental electrical source.
Chum lee
Edit: On further thought, you may need to increase the size of the hot lead (and the ground) to your trailer battery(s). The power wire from the alternator to the 7 pin connector probably wont be big enough to carry the needed amperage without excessive voltage drop to charge your battery bank in the time allowed. Also, you may have trouble with your alternator failing to recognize the state of charge in your house batteries. It's designed to look at the state of charge of the under hood battery. Most Class A motor homes (mine included) have a solenoid disconnect so that the house batteries are not connected to the chassis battery (and the alternator) unless the engine is running.
If you have a standard set of 2 - 6 volt wet cell deep cycle batteries, they are generally rated at 232 amp-hrs @ 12 volts at the 20 hour rating. We'll be generous and say 13.2 volts for this example. As I understand it, that means that the batteries contain 232 x 13.2 = 3062 watts available in theory, maximum, until the batteries are dead from a full charge.
So, if you have 3.062 kw available in storage and you use 1.23 kw per day you will get 3.062 / 1.23 = 2.49 days of use out of the batteries before they are dead, assuming no other loads on the batteries and that your inverter is 100% efficient, which it is not. It also assumes that the batteries can produce 13.2 volts until they are dead, which, they cannot.
So, yes you can drive and keep your residential refrigerator running strong, if you drive everyday while hooked up to your alternator in the tow vehicle. It's when you stop that you will have issues. If I were guessing, I'd say you would be good for sitting around for about a day before you need to find a supplemental electrical source.
Chum lee
Edit: On further thought, you may need to increase the size of the hot lead (and the ground) to your trailer battery(s). The power wire from the alternator to the 7 pin connector probably wont be big enough to carry the needed amperage without excessive voltage drop to charge your battery bank in the time allowed. Also, you may have trouble with your alternator failing to recognize the state of charge in your house batteries. It's designed to look at the state of charge of the under hood battery. Most Class A motor homes (mine included) have a solenoid disconnect so that the house batteries are not connected to the chassis battery (and the alternator) unless the engine is running.
