Alternative 12v Fridge Power

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Dangil

Dangil

10 Year
Joined
Aug 9, 2011
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Location
New Westminster BC
I was wondering if there those new compact "jump start" battery packs would be a viable alternative for powering a 12v fridge for a couple days when you are camped and the vehicle is off.

Something like this:
Amazon.com: Eveco Jump Starter 16800 Mah 800 Amp Peak Current Emergency Power Bank Supply Fit All 12v Car/truck: Automotive

I'm not an electrician, so I'm not sure about how to run the math on this.

16800 MAh = 16.8 Amp hours. Efficient fridges draw 2.5-3.0 Amps. Does this mean you'd only get 5-6 hours from one of these batteries?

Or is the 16800 MAh at 120 volts, so you would actually get 168 Amp hours at 12 volts.

It's been a while since I took Physics 12.
 
Solar is your best option IMO

Depleting a battery 50% is recommended for long life giving you only ~8AH to work with that I would still question. Over the years I have found a direct relationship between battery AH and weight and anything outside of that is a false claims.
 
Jump start batteries are designed to discharge high current (CCA) quickly. The aren't designed to run low current devices for long periods of time.

A typical group 27 sized deep cycle battery weighs about 50-60 lbs. A jump start weighs a couple lbs.

For the most part, the bigger and heavier a battery is, the more energy it can store.

A group size 27 deep cycle battery can run an efficient fridge (ARB) for maybe 2 days on low setting without killing the battery.

4 lbs vs 60 lbs.
 
Output Shaft said:
Jump start batteries are designed to discharge high current (CCA) quickly. The aren't designed to run low current devices for long periods of time.

A typical group 27 sized deep cycle battery weighs about 50-60 lbs. A jump start weighs a couple lbs.

For the most part, the bigger and heavier a battery is, the more energy it can store.

A group size 27 deep cycle battery can run an efficient fridge (ARB) for maybe 2 days on low setting without killing the battery.

4 lbs vs 60 lbs.
Click to expand...

For comparison a group 27 deep cycle is rated at ~90AH
 
I have heard of folks running a fridge off of one of those Goal Zero Yeti power packs while parked and have the truck charge the system while under way. Might be nice and easy for weekend use, but longer trips without drive time it might be a problem.
 
I have an Engel 45 liter and run it off of a pair of golf cart batteries and an 80 watt solar panel. Expensive and heavy but it allows for basically indefinite off grid cold beer. But yeah there's no free lunch.

Eric
 
There are some Grp 27 105 aH batteries around (expensive Lifelines), but I agree with Phil. Heavy = more. Also, as batteries age, they have less capacity even though they are still good, so figure that in the mix too.

So in the original question, a 16 aH battery has 8aH of useful capacity, so would allow your average fridge 2-2.5 hours of run time. Not very useful.

There is no free lunch in the battery /solar world. I like the idea of two 6 volt golf cart batteries in series, but there's no room under the hood for them. They are big, heavy and potentially dangerous in the rear of a wagon, so I think we're all basically stuck with about 100aH capacity batteries.

Solar is nice because it does 2 things. It charges your battery (duh!) but also supplies the load of your fridge all day, so you get to dark fully charged. I ran a 100 watt panel last year (which was sufficient) but I got a 160 watt panel at a good price for this year-going to try that.
 
Cruiserdrew said:
There are some Grp 27 105 aH batteries around (expensive Lifelines), but I agree with Phil. Heavy = more. Also, as batteries age, they have less capacity even though they are still good, so figure that in the mix too.

So in the original question, a 16 aH battery has 8aH of useful capacity, so would allow your average fridge 2-2.5 hours of run time. Not very useful.

There is no free lunch in the battery /solar world. I like the idea of two 6 volt golf cart batteries in series, but there's no room under the hood for them. They are big, heavy and potentially dangerous in the rear of a wagon, so I think we're all basically stuck with about 100aH capacity batteries.

Solar is nice because it does 2 things. It charges your battery (duh!) but also supplies the load of your fridge all day, so you get to dark fully charged. I ran a 100 watt panel last year (which was sufficient) but I got a 160 watt panel at a good price for this year-going to try that.
Click to expand...

Yep - my batteries are made here in town and were repaired I think for leaks so I got them at the outlet for cheap. 260 Ah I think. Very heavy (just looked at the brochure - 80 lbs a piece.) They typically ride in the bed of the Tacoma and I know they're there. But as you allude to the price of solar cells is coming down so much that I can see more solar cells less battery being the way to go (especially since solar cells have a much longer life than lead acid batteries - mine have been growing old in the basement all winter.) i just got a 62 I'm refurbing and I'd like to ditch the GC batteries and add a second one under the hood as you describe.

When partially overcast my 80W panel can barely keep the batteries topped off depending on temp and usage of course.

Eric
 
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