Mike, in the sentence about the 12 volt system powering the refrigerator propane controls you wrote, "15 or 20 watts which is about 1.5 amps at 120 volts."
It looks like you slipped a decimal point, or maybe got 120 VAC switched with 12VDC. At 120 volts a 20 watt draw takes 0.167 amps, ignoring small inefficiencies. At 12 volts, 20 watts would require 1.67 amps, 15 watts requires 1.25 amps, again ignoring inefficiencies.
I’ve always assumed that it is not a good idea run a 3-way absorption fridge on 12V DC while driving because that would require more current than can be provided through the 7-way trailer wiring without too much voltage drop and could result in draining the RV battery and / or the tow vehicle battery (if the alternator can’t make up the difference). With DC fridges drawing so much less power, it would seem that driving with a DC fridge on might work just fine. I’d be curious to hear what folks have experienced?
You are correct that a 7-way plug can’t supply enough current to power a 3-way absorption fridge. And it won’t be able to power a residential refrigerator through an inverter. But it can probably power a 12-volt DC compressor fridge. Great idea for an article!
Mike, in the sentence about the 12 volt system powering the refrigerator propane controls you wrote, "15 or 20 watts which is about 1.5 amps at 120 volts."
It looks like you slipped a decimal point, or maybe got 120 VAC switched with 12VDC. At 120 volts a 20 watt draw takes 0.167 amps, ignoring small inefficiencies. At 12 volts, 20 watts would require 1.67 amps, 15 watts requires 1.25 amps, again ignoring inefficiencies.
Oops, that should be 12 volts. Let’s blame my 20/800 vision. Thanks for the correction. 😁
12v also runs the fan on the fridge
I’ve always assumed that it is not a good idea run a 3-way absorption fridge on 12V DC while driving because that would require more current than can be provided through the 7-way trailer wiring without too much voltage drop and could result in draining the RV battery and / or the tow vehicle battery (if the alternator can’t make up the difference). With DC fridges drawing so much less power, it would seem that driving with a DC fridge on might work just fine. I’d be curious to hear what folks have experienced?
You are correct that a 7-way plug can’t supply enough current to power a 3-way absorption fridge. And it won’t be able to power a residential refrigerator through an inverter. But it can probably power a 12-volt DC compressor fridge. Great idea for an article!
Please do write an article on this!