Deep Cycle battery question

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Old 04-19-09, 06:05 AM
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Deep Cycle battery question

Our rv refrigerator stopped working and plan on installing a cheap dorm fridge in its place. I also plan on getting a LifeLine battery that has 100 ah along with 1000 watt inverter. I think the fridge draws like 5-8 amps when the compressor is running. I need to know how long will this battery run the fridge? I only need to have it run it for 8-10 hours while I'm at work. Then the truck will charge going down the road or will charge through the camper inverter while camping. Thanks for your time!
 
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Old 04-19-09, 09:36 PM
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RV Frige

This is not going to answer your questions but have your frige checked,it might be cheaper to fix it than buy all the stuff you are talking about. Mine quit working on gas and a 30 dollar transformer fixed it. Another thing you quoted the draw when running but when the thing starts is when the draw is high. I had a rig like this and if you had to string cords a long way to the source every time the frig started it would trip the breakers. Also it was so poorly insulated the it ran every 5 minutes. Good Luck RW
 
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Old 04-20-09, 05:47 AM
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Sorry, a fridge running at 750 watts will run less than one hour on a 100 ah battery.
You will need a bank of ten 100 ah batteries but you will have a problem recharging them.

What makes an RV fridge so attractive is that they are very efficient, energy wise, at what they do.
You will need to be happy running it only when plugged in or replace it with another RV unit.
 
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Old 04-21-09, 10:57 AM
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went to walmart last night and the 100 ah battery said it would last 10 hours at a 6 amp draw before it was drained. why wouldnt that work? the fridge is only running part time too.
 
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Old 04-21-09, 12:27 PM
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Right, you are drawing 12 volts at 6 amps which is 72 watts.
Your fridge will be drawing 6 amps at 120 volts which is 720 watts of power consumed.
720 watts plus about 15% loss for the inverter will be about 825 watts.

If you are buying a deep cycle battery from Walmart it will be the 24 group size for their small one and 27 group for the bigger one.
Also, if it is a dual purpose marine type you will get less performance than a true deep cycle.

Here is a good chart that may make it easier to understand.
 
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Old 04-21-09, 03:19 PM
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the 6 amps is only when the compressor is running. The rest of the time its around 1.5 amps. figured the compressor would run around 30-40 percent of the time. depending on outside temp.
 
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Old 04-21-09, 04:23 PM
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I am not sure if you understand what I am telling you.

A fridge that draws 8 amps when connected to an inverter that is connected to the larger size 27 series deep cycle battery will run for less than one hour before the battery charge is used up.

If your fridge runs 40% of the time then you might get two and a half hours run time.
Like I said, if you wanted the fridge to run overnight you would need many batteries.
 
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