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post #6 of (permalink) Old 17-09-2020, 19:59 Thread Starter
Bryce Lawrence
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Join Date: Sep 2020
Location: Hamburg, Germany
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Quote:
Originally Posted by Penquin View Post
Agree totall with Ray; you SHOULD have three ways of powering your fridge;

1. Mains voltage (240 v nominally), this should be used WHENEVER POSSIBLE to prechill the fridge before a trip and during any trip where mains EHU is available,

2. 12v this is the most inefficient way of cooling the fridge, the current drain is too high for solar panels even here in the very sunny South of France at mid-day, 12v should ONLY be used while the engine is actually running and the wiring should prevent any other use of the 12v system for cooling, if not then there is a SERIOUS fault in the wiring. The 12 v is so inefficient that the fridge thermostat is bypassed while on 12 v so the fridge in theory gets colder and colder,

3. Gas, this should be used when the vehicle is on a site IF NO MAINS EHU AVAILABLE, but only if, it may require extra cooling fans for really efficient operation in hot weather but is VERY efficient at cooking the fridge down (it actually puts in about four times as much cooking power than even mains EHU. It must NEVER be used while underway cure to a serious fire risk in the event of a road traffic collision. Seen one MH burn out within 7 minutes, fortunately we were able to get the sole occupant out just before the cylinders exploded.

Please use this as fairly fundamental advice, you CANNOT operate your fridge from solar panels - they only deliver their maximum output when the sun is directly overhead - and how often does that happen each day ? Of course, there is absolutely NO charge if cloudy, raining, evening, ,orning or night in other words most of the 24/7. Our twin 85w panels + a portable 7w panel deliver just over 4.5a here at mid-day but we have recently had most days in the mid 30's....... with full sun and zero cloud and a <1% chance of rain during the day. Can you match those conditions ?
My 260W panels keep my battery fully charged on a rainy day at about 20 degrees, so the battery is only needed at night. In 100% perfect conditions, my panels need no more than 2 hours to supply a full days fridge consumption. Typically the battery is fully charged by lunchtime.
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