Mark replied:

John,

We have hired the 39 Liter Engel a couple of times and found that it would generally run around 2 days on a fully charged battery. There are a lot of factors that may increase/decrease the run time such as ambient temperature and size of battery (amp hours) as well as the number of times the fridge is opened etc. From memory I seem to recall that the Engel 39L would draw around 3.5 amps while the compressor was running & 0.7 amps when only the fan was running, therefore your probably looking at 1.5 amps per hour on average and with a good 80 amp hour battery you will probably get around 60 amp hours out of it before the fridge stops working due to the voltage drop. Thats 40 hours if you leave it running, you can turn the fridge off at night if its cool enough. Its also important to leave enough space around the fridge to allow the fan to work, also if leaving it in the car try and keep in the shade and where possible leave windows and doors open to keep a good airflow.

Nigel replied:

Australian 4WD Monthly recently did a fridge comparison in their September edition. They ran the fridges for 2 days in a test lab were the temperature was varied from 15 to 55 degrees over a normal day cycle to simulate desert usage. The average current draw for the whole cycle was 1.6 amps for the Engel/ARB (the lowest of any tested). To find out how long a battery will power the fridge you need to find out it's capacity in Amp Hours (Ah). Then you simply divide the Ah by the average current draw to find out how many hours it will run.

Nigel replied:

One more thing - I agree with mark that you will rarely get as many Ah out of a battery as is claimed, except under ideal conditions when the battery is brand new. So don't forget to leave a safety margin so you don't end up with rotten food. Also the flattening a standard car battery to the point where the fridge cuts out will reduce the life of the battery significantly. Best to check with a battery expert but from memory I think 11.8 volts may be the lowest you
should go before recharging if you want your battery to have a long and healthy life.

Tony replied:

John, I have a TailBlaza 60l and with a new 95ah deep cycle battery.I get about 2 and a half days to 3 days.I turn the fridge off at night otherwise I get 2 days. This fridge has 3 inches of insulation and will stay cold for 2 days after the battery has gone flat.

John Eaton replied:

Many Many Thanks to all who replied,uptill now I have not been able to get a clear answer.Thank you Again. John

James replied:

John, I bought one of the new 41 litre ARB/Engel fridges in May this year. I live in Darwin and travel around up here. I had a 70 Ah deep cycle battery fitted at the same time. I went through the Kimberleys in June and left the fridge on No. 2 setting (drinks icy cold) for 48 hours without any troubles. I have found the fridge to be one of my best investments and it goes great as a bar fridge at home. Good luck.