As many of you have found, when ambient temperature is really high, the older ammonia fridges have difficulty getting down to food safe temperatures. The issue is poor cooling of the absorber and condenser, compounded by the heat from the boiler warming the space between the fridge
and rear wall. After much reading and experimenting I have installed a fan to augment the cooling of the absorber and condenser.
I mostly dry camp and so use the main battery
just for lighting
(all LED), and easily get a week or more. My daily consumption is usually in the order of 3 to 5 AHr/day.
The fan draws 300ma or about 7.2AHr/day and would significantly up my battery
consumption. I have found that the fridge
is usually about 4degree C by morning without the fan and then creeps up as the day gets hot, so I see no need for the fan at night, so I now power the fan with a small solar panel
and the fan runs only when the sun is out. It only needs to be about a 5 watt panel and I connect it directly to the fan...no battery
. It loads the panel to around 12V, but I have seen it as high as 15V. It is an $8 fan so if the higher voltage ever smokes it I will simply replace it, but I have many days of full sun so far and no problem. Another possibility is to run the fan off the battery, and connect the solar panel
to the battery to replace the fan consumption. That would keep the fan voltage down to battery voltage. I prefer the fan directly driven by the solar panel
way as I don't have to monitor it.
One more thing I found was that over the years some of the vent fins have closed up a bit and any improvement in ventilation makes the fridge
run better, so I took a screw driver and bent the fins out a bit.
In the picture above, I have only done the fins on the right and you can see the difference.
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