Battery Boosters for running a 12 volt fridge

fzsk4p

Adventurer
The Edgestar showed up the other day.
Works good but I think the latches are a bit cheesy.

Anyways.....Several folks have talked about using one of those portable jump start boxes`s to provide 12 volts overnight. Instead of a battery.

Has anyone done any research on what a good one is and how well it works in place of a deep cycle battery ?

I did a search using "Jump Start" as the key words and nothing much came up.

Thanks !!
 
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mountainpete

Spamicus Eliminatus
I've done it a few times. I have actually run my fridge for over two days in the garage with it and still had power left.

The unit I have was simply from Costco. Not sure what brand it is.

Pete
 

Grizzlybait

New member
I've thought about that myself. Here's what I've concluded -- it will work in a pinch, but ...

I have a 24 litre Mobicool thermoelectric cooler. It draws about 4 amps @ 12 volts DC. That's fairly average for thermoelectric coolers. They are not very efficient.

I also have a pretty good size jumper pack, and the gel cel battery is rated at 22 amp-hours. Doing the math, that would give me about 5 1/2 hours run time. That's not really very adequate.

Now, I know there are even larger capacity jumper packs, but now you're talking some real money. The biggest one I can find costs about CAD$200, and is still only 28 Ah.

Another thing to consider is that even with "deep cycle" batteries, the more times you completely discharge them, the shorter the life of the battery.

For that kind of money, you might as well get a fairly hefty marine deep-cycle battery wired to your electrical system with a battery isolator. That will do the job, and it will last.

For my own purposes, what I've done is added an extra layer of insulation to my cooler and I use ice packs. It's not perfect, and it takes away some of the storage capacity of my cooler, but when it's plugged in during the day (when the engine is usually running), I find the ice will last a few days. Even better is using about 4-5 lbs. of dry ice, wrapped in newspaper on the bottom. I've gotten a good three days use that way. If your cooler is larger than mine, you can add more ice, and get more time out of it.

Hope that helps.

Edit -- just realized your Edgestar is a *real* refrigerator, but the same principles apply regarding battery use. The current draw is in the same ballpark.
 
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fzsk4p

Adventurer
Good post Grizz.

Looked up again and the Edgestar runs @ DC 5.5A/hour. Not sure if these are max cooling numbers where the compressor is running full tilt or not. So a 25 amp/hour booster pack would run about 4 hours at the above stated load.

Wonder if the booster could be recharged through the vehicle 12 volt power supply along with the fridge running during the daytime ? Have a 140 amp alternator. That way after a long day on the trail it would be charged up enough to last most the night.

Then again, wonder how many discharge cycles would a booster pack could take before it would`nt take a full charge anymore ?
 

Grizzlybait

New member
Looked up again and the Edgestar runs @ DC 5.5A/hour. Not sure if these are max cooling numbers where the compressor is running full tilt or not.

I'd assume a worst-case, and add a bit for a safety margin.

I'm sure you'd get some kind of a charge on the booster during the day. The charging rate is pretty low, though. I don't think your alternator would be the issue here. On my booster pack, to charge it from totally dead with the ac adapter, takes somewhere around 18 to 24 hours. Not sure if the charge current is limited when charging from a lighter socket, though.

But since you've got an actual fridge, and it gets colder, I'd almost think if you had ice packs in it, you could freeze those during the day, and at night they'd help keep the inside cool, no?

Outside of that, I'd go with rigging up some sort of proper auxilliary battery that's got a sufficient capacity. I just checked, and even a $100 marine deep cycle battery has a 93 Ah capacity. So then the only question is where to put it.
 

jfarsang

Adventurer
Good post Grizz.

Looked up again and the Edgestar runs @ DC 5.5A/hour. Not sure if these are max cooling numbers where the compressor is running full tilt or not. So a 25 amp/hour booster pack would run about 4 hours at the above stated load.

Wonder if the booster could be recharged through the vehicle 12 volt power supply along with the fridge running during the daytime ? Have a 140 amp alternator. That way after a long day on the trail it would be charged up enough to last most the night.

Then again, wonder how many discharge cycles would a booster pack could take before it would`nt take a full charge anymore ?

The edgestar won't run @ 5.5A/hour unless you have the top open and nothing inside so it constantly runs the compressor.

If you have it 80-100% full inside and rarely open it, it won't consume much at all. You can hear when the compressor is running throughout the day. It's not often.
 
M

MuddyOval

Guest
I haven't tried my Edgestar in the field yet, but my Engel is usually fine if I turn it off for the night. When I used it on the wife's truck which only has one battery, we just unplugged it and in the morning plugged it back in- unless it's the middle of summer and hot overnight, it would still stay cold overnight. We'd usually drop the temp a little more than usual a couple hours before unhooking it.
 

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