Residential Fridge - battery power

thegriffins wrote:
Thank you for responding. I hope I have all of the information you need to help me.
1. The refrigerator is Energy Star. It is a Frigidaire LFHT1817LB6 - 18.2 cu ft - The paper work says 6 amp / 115 volts.

2. The inverter is WIN - 12X20B3RT / output current amps up to 16.7 amps, peak output 70 amps, output continuous watts 2000.

3. We also have a solar panel

4. Batteries are Energizer Deep Cycle Marine/RV - RC180/12 volt / Marine cranking amps 840/cold cranking amps 675/E27DC. There are 3 of them.

Good to go. Just watch voltage is not dropping much below 12.0 under steady load.

John & Angela wrote:

Hmmmmm. Maybe I misunderstood the question. If the original poster is asking if the load of a fridge fed through an inverter will hurt the batteries of course not.

The original question was, let's say, not totally clear. It was "I turn on the inverter will it run the refrigerator without harming the batteries"?

There are 2 things that may harm the battery - high current or low SOC.

Feeding the fridge through inverter is neither good nor bad in itself. 12A current @12V is not harmful for 3*90 AH bank. One note on inverters, though. MSW inverters tend to do some harm to motors - they are running hotter - but it's hard to tell how much harm and whether this is worth extra cost of PSW inverter.

He will harm the batteries after a 20-24 hours of running the fridge. The more he does this (i.e. the lower drops the SOC), the more he harms them.

He will not harm the batteries while running the fridge when driving 5-6 hours.

I'm just gonna give a couple of tips...

I put six or eight ice cubes in a zip lock bag or plastic container with a good lid...and put it in the freezer as a safety check. If I have a worry, I just look at them or shake them. If they retain their shape, then the freezer has stayed cold. ( If they melted and refroze, you're gonna know something went wrong. If they are floating in water... something IS wrong.)

I have an indoor outdoor thermometer setup. One sensor inside the freezer. One is inside the fridge. The read out is on the kitchen table where I can easily see it. No need to open the door to check how cold it is inside. It's the first thing I look at before I open the fridge or the freezer.

If you buy the right kind, it will even beep a warning when the set temp get's below or above a certain temperature.

Hi,

Running the inverter while driving will be a piece of cake. I do this for my absorption fridge and have zero problems. It draws far more energy than your residential fridge.

You will have to make sure the inverter does power the fridge outlet. You will need to turn off the converter (if you have one).

True. :). Your inverter will hardly even know its on. Kinda like running a couple of TV's. Assuming here you have some sort of factory installed inverter in your coach.

Happy trails.

I'm sorry for all the confusion. We have already replaced the Norcold with a residential. We only want to run it while driving from point A to point B. We don't dry camp, ever. We always camp with electricity. We had read that when we left in the morning the residential would stay cold enough for a few hours, then run the generator when we stopped for lunch, then it should be OK until we arrived at our destination. However, we found that we had to run the generator more often than that. Today we were thinking about the inverter and wondered if we could just turn that on instead of the generator. We have never really used the inverter, so it's all new to us. What I am gathering from all of the conversation is that it is safe to do what I just described with the equipment we have. True??? (Thank you all so much for helping me!)

Almot wrote:

John & Angela wrote:
What Tex said. No worrys about hurting the batteries as a fridge doesn't draw much. To put it in perspective, your microwave draws about 14 times the current as your fridge does.

I don't think Tex said or meant any of this. There is a BIG worry about hurting batteries with 120V fridge, unless battery bank is big or you run the fridge only a short time. Tex has a big 440 bank, 4*220AH @6V = 440 AH@12V. And yet, after approximately 24 hours, his charge drops low. The OP has almost twice smaller bank, which means they are good for maybe 15-20 hours. Or less than 15 hours, if they have more loads than Tex, besides the fridge. This would work if they are always plugged in at the camp, and need the battery while on the road only.

Yes, microwave draws 14 times more current than 120V fridge, but it also runs total 14 times less than a fridge, over 24 hours period. Though, due to Peukert effect the high current drawn by MW may draw more charge from the batteries than the fridge, even if KWH @120V over 24 hrs period is the same.

Hmmmmm. Maybe I misunderstood the question. If the original poster is asking if the load of a fridge fed through an inverter will hurt the batteries of course not. Its about the same as a laptop (at lesat our clunky old toshiba) but actually probably draws less as the fridge is only on about a third of the time. If he is asking if deep cycling a battery or batterys will hurt them, well I suppose if he ran them flat every day ot would but most inverters cut off before then so, yah it will deep cycle them, but they are built for that. The original poster may have to clarify what his concerns are.

Almot wrote:

John & Angela wrote:
What Tex said. No worrys about hurting the batteries as a fridge doesn't draw much. To put it in perspective, your microwave draws about 14 times the current as your fridge does.

I don't think Tex said or meant any of this. There is a BIG worry about hurting batteries with 120V fridge, unless battery bank is big or you run the fridge only a short time. Tex has a big 440 bank, 4*220AH @6V = 440 AH@12V. And yet, after approximately 24 hours, his charge drops low. The OP has almost twice smaller bank, which means they are good for maybe 15-20 hours. Or less than 15 hours, if they have more loads than Tex, besides the fridge. This would work if they are always plugged in at the camp, and need the battery while on the road only.

Yes, microwave draws 14 times more current than 120V fridge, but it also runs total 14 times less than a fridge, over 24 hours period. Though, due to Peukert effect the high current drawn by MW may draw more charge from the batteries than the fridge, even if KWH @120V over 24 hrs period is the same.

Sorry, but his fridge will NOT draw enough to hurt his batteries during any day they are driving. Also, the specs say 1.2 amps and he will find in actual use, it will probably be just like ours < ¾a draw. Ours specified it drew 1.3a and actual with a meter is way less, as I said. Also, with a solar panel and alternator while driving, there is NO chance of drawing the batteries down. My use is with all electronics and normal boondocking and have never hurt our batteries.

John & Angela wrote:
What Tex said. No worrys about hurting the batteries as a fridge doesn't draw much. To put it in perspective, your microwave draws about 14 times the current as your fridge does.

I don't think Tex said or meant any of this. There is a BIG worry about hurting batteries with 120V fridge, unless battery bank is big or you run the fridge only a short time. Tex has a big 440 bank, 4*220AH @6V = 440 AH@12V. And yet, after approximately 24 hours, his charge drops low. The OP has almost twice smaller bank, which means they are good for maybe 15-20 hours. Or less than 15 hours, if they have more loads than Tex, besides the fridge. This would work if they are always plugged in at the camp, and need the battery while on the road only.

Yes, microwave draws 14 times more current than 120V fridge, but it also runs total 14 times less than a fridge, over 24 hours period. Though, due to Peukert effect the high current drawn by MW may draw more charge from the batteries than the fridge, even if KWH @120V over 24 hrs period is the same.