Sunday, Mar 27, 2011 at 21:34
Donna,
Your question is a bit ambiguous as to the "permanent" requirement.
If you have a good dual battery setup, the auxiliary battery will be charged by the vehicle alternator and that may be all you need if you are travelling daily.
If however, you intend to be stationary for a couple of days or more, the requirements change.
I have a 75Ah thumper running my 40 litre Engel and is charged by the vehicle alternator when on the move. I also have an 80 watt folding solar panel array to add a charge to the portable battery system when stationary and have found this setup to be adequate for my needs.
When I upgraded my vehicle I added a new auxiliary battery system consisting of a Flyer battery pack containing a 100Ah AGM battery and also capable of being charged by the alternator.
The fridge is connected to the Flyer while travelling, then to the Thumper when camping, with the solar panels connected to add a charge back into the battery pack during daylight hours. The Flyer then is available as a back up battery system should inclement weather negate the input of the solar panels.
There is no "perfect" system as environmental conditions change, but as a general minimum for a 40 litre fridge on "fridge" setting (not freezer), an 80 watt solar panel should be adequate to put in as much charge to the battery during daylight hours, as the fridge draws from the battery over a 24 hour period.
A modern 40 litre fridge such as the Engel will run at a maximum of 2.5 amps per hour (usually somewhat less) and an 80 watt solar panel is capable of putting back around 5 amps per hour in good sunny conditions.
Bill.
AnswerID:
449412