I dont think 3 way runs full time 12v or DC ? Try it for 12hours ? At night it wont or shouldnt require the same load from battery . If it lasts 10 -12 hours through the day . What is the running load of fridge ? There is no info ?
I have had to replace the heater element in our 3 way Dometic 90 L fridge in our caravan (I also replaced the whole fridge a few years ago as well). The thermostat operates on AC, but the The gas seems DC circuit doesn't use the thermostat at all - it just goes all the time that the DC source is selected. The gas system also doesn't use the thermostat.
I have a 28L Waeco compressor fridge. The 28, 35, 40 & 50 litre fridges all use much the same.
Rated current 28L 6.5amps but typically when the compressor is running it's about 4.0 amps, usually around 3.8amps.
Waeco says 0.75AH per hour 5°C internal, 32°C ambient temperature. So 18AH per 24 hours.
Rated amps 35 & 40L 7.0amps, 50L 7.8amps. So about 2/3 of that in typical running situations.
I have added additional insulation. So my 28L uses up to 15AH per 24 hours running as a fridge. So in theory I can get about a week off my 4 x 26AH gel batteries. But often we go 4 days & not both dragging out the solar panels.
If your fridge is a 3 way fridge it will use 15AH per hour running off 12 volts, frightening stuff!
How much energy the fridge uses largely depends upon ambient temperature.
Tests I did on a 60L fridge/freezer with the fridge set to +2C and the freezer set to -12C indicated a daily power draw between 25Ah and 50Ah (at 12V) depending upon ambient, so if we say an average of 37Ah and only allow the battery to be depleted to 50% then you have 60Ah available which equates to a run time of around 40 hours.
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"I beseech you in the bowels of Christ think it possible you may be mistaken"
Oliver Cromwell, 3rd August 1650 - in a letter to the General Assembly of the Kirk of Scotland
I have a 120ah battery how long would it keep my dometic fridge /freezer frozen
It depends on what size your fridge is and are you running as all freezer and or fridge My 65 litre Ironman would drain a 120 amp running on freezer -15 degrees with no charging being done within 8 hours or two to three days running at fridge 4 degrees.Also depends on whats in your fridge ie ice cream and bread dont freeze as well as meat and liquids.Also hot weather like constant days over 35 degrees has a big effect on cooling .I now run 3 x 120 batteries in the car with a red arc 25 amp dc dc charger for driving and a 180 watt solar permanently on the roof when not driving
Cheers
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John
2017 dmax lovells upgrade full CSM trade aluminium canopy,3.5 m quintrex tinny and rear boat loader mangrove jack aluminium trailer
When you add insulation cover the door. They are poorly insulated.
The best insulation in vacuum panels but one single accidental puncture & the vacuum is stuffed.
The next best product is Aerogel which if used in a fixed built in situation is the best insulation.
Failing that about 150mm thickness is roughly the maximum cross over point of maximum thickness for foam insulation. The thicker the insulation the greater the eventual external surface area. So there is a cross over point where any more thickness is of realy no use.
But any insulation is better than what the fridge comes with, & is a lot lighter than more batteries & solar.
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Procrastination, mankind's greatest labour saving device!
50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.
When you add insulation cover the door. They are poorly insulated.
The best insulation in vacuum panels but one single accidental puncture & the vacuum is stuffed.
The next best product is Aerogel which if used in a fixed built in situation is the best insulation.
Failing that about 150mm thickness is roughly the maximum cross over point of maximum thickness for foam insulation. The thicker the insulation the greater the eventual external surface area. So there is a cross over point where any more thickness is of realy no use.
But any insulation is better than what the fridge comes with, & is a lot lighter than more batteries & solar.
When I bought my 65L brass monkey I ran it for 24hrs empty, fridge 4c freezer -10c it used 28Ah, then added bottles of chilled water and on the same settings ran it for another 24 hours and it used 25Ah, Just came home from 4 days in the bush and it seemed to use a similar amount of power but I couldn't get accurate information as my cheap power meter count in both input and output and I was running 2 145w panels to keep the battery charged, but it kept my food perfectly over the 4 days. I'm running a 120Ah AGM atm.
I get nearly 3 weeks out of a 9kg bottle of gas in my 3 way portable. So I will always stick to a 3 way, but they are really heavy to carry as well as having a place for the bottle, and also finding gas if you are remote, although we don't intend to be remote anymore so this wont be a problem for us in the future.
