I am new to caravaning. When I had my tow ball put on, I asked for an isolation switch to be added. (Who knows where that is, under bonnet I presume). I have since had two more solar panels put on the roof and thought I could run my fridge on 12V from the house battery when stationary. After paying thousands of dollars I am now told by the installers that my type of fridge which is not a compression fridge (its dometic 3way) is only designed for battery use when driving along. Is this true? The only other things atm that I am using 12V for is water pump and lighting which is overkill for the amount of panels and extra battery I now have if I cant run fridge on battery when stationery. I did try running on house battery overnight & even though the volt gauge showed 13, the freezer was defrosting in the morning. This is as clear as I can get, sorry. I would really like to understand how it all works & get some clarity before I take off on a long trip. Thanks
-- Edited by Yatra on Monday 5th of August 2024 09:27:31 AM
Welcome to the forum Yatra. A good first question, although it would have been better in the Technical section.
The 12 volt element in a 3 way fridge is not designed to run the fridge all the time, but to help sustain it while on the move. You did not say how big the fridge is, but my 186 litre Dometic draws 25 amps on 12 volts. That is a LOT of current draw for a van battery system. It is also a constant draw, not cycling on and off.
Over 24 hours, that means 600 amp/hours. If you have a typical basic battery in the van it is probably about 100-140 amp hour capacity. You would need more than triple that capacity to store enough to be able to run it all night ... just one night.
Then comes the solar requirements. Those 600 amp/hours need to be replenished while the sun is shining. Assuming 8 hours of charging at full capacity (optimistic) you would need a solar system that produces 80 amps (80 amps for 8 hours = 640 amp/hours). But if there is a cloudy day your food starts going off.
So, running a larger 3 way fridge off 12 volts is not a very practical solution. Assuming you are freecamping, can you run it on LPG?
Swapping the fridge for a compressor fridge is a solution, although costly. Your solar will probably be enough but you need battery capacity. If you provide details of what you have we can get a bit closer.
