rruff
Explorer
The least efficient frig was 1.5A average consumption. The most efficient was .73A. http://www.arbusa.com/uploads/Newsletter/ARBmegaFridgeComparo.pdf
Solar/Battery Help
- Thread starter Jdavenport
- Start date
The least efficient frig was 1.5A average consumption. The most efficient was .73A. http://www.arbusa.com/uploads/Newsletter/ARBmegaFridgeComparo.pdf
broncobowsher
Adventurer
For reference point, I have a 70W rated solar panel with a PWM charge controller that does a real nice job of running an ARB fridge (in fridge mode, not freezer). Fixed panel mounted flat on the roof. I really wanted a 100W panel after doing all the math and factoring in the losses (and there are many, many, MANY losses) in the system. From low sunload in the winter, poor aiming (none), the loss in the charge controller, etc. In full freeze mode, it will suck a single battery really low overnight in the summer. Did that once on a grocery store run and forgot to turn it off when I got home.
Yes, tie the house batteries into the engines alternator. If you get a couple bad days of weather you can start the engine and idle it for an hour or so to get a charge back in them.
Toaster oven. Don't count on solar to run that. Big invertor and run the engine while running the oven. At home I am a huge toaster oven user. Have not incorporated it into travel (yet). But I would like to. Need a bigger rig to house it first.
Yes, tie the house batteries into the engines alternator. If you get a couple bad days of weather you can start the engine and idle it for an hour or so to get a charge back in them.
Toaster oven. Don't count on solar to run that. Big invertor and run the engine while running the oven. At home I am a huge toaster oven user. Have not incorporated it into travel (yet). But I would like to. Need a bigger rig to house it first.
Traveling 2gether Journal
Adventurer
I read a bunch of reviews similar to this one before getting my fridge. They are a useful comparison when trying to decide which fridge might meet your needs best, but don't take these numbers as the efficiency you should expect or you will greatly underestimate the amount of power you need, like I did
The posted article is nice because they describe their process. They pre loaded the fridges and got everything to operating temperature over night before starting the test. then didn't open them at all during the tests from which they collected this efficiently data. It's probably the most accurate way to do a comparison, but doesn't simulate real world use at all.
Think about how often you will open the fridge in an evening of making diner and drinking a few beverages. Each time you open the door you let out cold and the fridge has to work hard until it cools everything back down to the set temp. It probably takes about the same time it takes you to come back for another drink
And if your like me, after a day or two at camp its time to restock the fridge with warm beverages because I can't fit 5 days worth of food and drink in the fridge at once. Now the fridge is going to be working hard for a while to catch up.
I believe many manufacturers use the same compressors throughout their product lines. so a 44L unit may have the same compressor as a 66L unit. Their efficiency results would probably be similar during test conditions, but in real world conditions the compressor would have longer run times to cool down the larger cabinet every time you open it.
I'm not an expert, but as noted my fridge consumes the vast majority of my power, so I was paying close attention for a while before deciding that nothing was wrong with my fridge, its just the price I pay for running a large fridge freezer in the tropics.
DaveInDenver
Middle Income Semi-Redneck
If you're careful you probably don't really let out much cold air when you open the lid. Remember physics, cold air is heavier than warm, so if you swing the lid open slowly so as not to disturb the air too much it should just sit there. Obviously you stir things up by adding and removing things, but if you pack intelligently you might only really have to get the stuff at the bottom infrequently, which is what really upsets things I imagine.
Your point, then, is very valid. That real world usage impacts things heavily so the only way to really compare consumption is to not add in that variable. So from fridge-to-fridge you compare the draw with the same conditions, full, empty, starting hot, starting cold, etc. and pick the one that meets your power goals. The way you use each is probably going to be the same, so that marginal change is uniform across all of them to you (assuming they are similar size and shape)
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Traveling 2gether Journal
Adventurer
Good point Dave. These comparison articles are great for shopping.
To clarify my point was just that you shouldn't use the efficiency ratings posted in these articles when calculating your expected power demands in the design of your solar/battery system or you will under estimate your needs.
DaveInDenver
Middle Income Semi-Redneck
Makes sense completely, definitely true. Published specifications, tests and other's results are handy but you 100% need to measure for yourself, in your mounted location and how you use it. Another thing I found that impacts consumption is the side of the truck you mount it on if it's near windows as it may be shaded or not more often. Also if an exhaust pipe runs under it may heat up faster.