Residential Fridge. Inverter Time?

[sandy43]

Those with residential refrigerators. When using your inverter to operate the fridge when NOT plugged into AC power, how many hours will it continue to produce power for the fridge before it needs access to AC power?

[sourdough]

Don't know because I don't want to find out....which would mean I depleted the batteries. Maybe overnite for 2 12v but others may have found out and can post.

[Javi]

Since I don't boondock and only have one 24 series battery for the inverter I don't care to find out. 😁

[chuckster57]

There is probably a formula for figuring it out. Your DC load will factor in too, like the LP detector, radio presets, any lights you turn on, water pump and furnace.

[tech740]

I can go 13 hours with only the investor powered and be at 55-60% charge. I had to do this recently and checked voltage on the batteries every hour in a parking lot. I retired my disconnect so only the inventor is on the switch side and moved everything else to the load side of the switch.

[rbrdriver]

I observed on the Trimetric meter we have that whenever the compressor on our fridge is running it is usually drawing around 9 to 10 amps, so therefore it's going to depend on how long your run cycle is, and how large your battery bank is, and also if you have solar panels.

[sandy43]

I just talked to the inverter manufacturer which is WFCO. Model #WF-5110R. The tech guy said theirs no set time limit. He said do the math, battery amps divided by fridge amps. Ex: A single battery is 700 amps and the fridge pulls about 10 amps which gives me about 7 hours of use before AC power is needed. Being I have 2 inverter batteries, not sure how that's calculated. I suppose I double the battery amps, I would think. He also said to never run your batteries completely down. He recommends, with good batteries, an 6-8 hour trip would be no problem. This info helped me, I hope it helps others. Any additional info would be appreciated.

[Javi]

Originally Posted by sandy43

I just talked to the inverter manufacturer which is WFCO. Model #WF-5110R. The tech guy said theirs no set time limit. He said do the math, battery amps divided by fridge amps. Ex: A single battery is 700 amps and the fridge pulls about 10 amps which gives me about 7 hours of use before AC power is needed. Being I have 2 inverter batteries, not sure how that's calculated. I suppose I double the battery amps, I would think. He also said to never run your batteries completely down. He recommends, with good batteries, an 6-8 hour trip would be no problem. This info helped me, I hope it helps others. Any additional info would be appreciated.

If you're driving the battery is being charged...

[dutchmensport]

We had truck trouble earlier this year and ended up getting the trailer towed to the nearest motel while the truck was being repaired. We were there for 3 nights. The trailer was not plugged into shore power and we were most concerned about the contents of the refrigerator. It was packed! Lots of frozen meat, milk, you name it. This happened the first day out. We hadn't even made it to our first nights destination yet.

Meanwhile, we stayed in the motel and the Montana had only the original 12 volt battery and no way to reach a power cord anywhere to plug in the camper.

We managed to keep the refrigerator cold, and things frozen in the freezer for 3 nights, and there was still enough power remaining to raise and lower the front landing gear to hitch-up.

How did we do it?

I turned on the inverter and flipped the battery kill switch and let the refrigerator run about 30 minutes every 5-6 hours over that 4 day period. The residential refrigerator cools very fast and stays cold for a long time if the door is not opened and closed all the time. We took our drinks into the motel room and used the little refrigerator there, and didn't get into the camper refrigerator unless we absolutely had too.

On another trip, we over estimated and ended up getting too tired driving, but could not find a campground anywhere for a quick over night. We found a motel, enjoyed the swimming pool and the morning breakfast. Meanwhile, the truck and trailer sat in the parking lot over night. Next morning when we left, the inverter was still purring away. I think we were parked about 13 or 14 hours.

[flybouy]

Originally Posted by sandy43

I just talked to the inverter manufacturer which is WFCO. Model #WF-5110R. The tech guy said theirs no set time limit. He said do the math, battery amps divided by fridge amps. Ex: A single battery is 700 amps and the fridge pulls about 10 amps which gives me about 7 hours of use before AC power is needed. Being I have 2 inverter batteries, not sure how that's calculated. I suppose I double the battery amps, I would think. He also said to never run your batteries completely down. He recommends, with good batteries, an 6-8 hour trip would be no problem. This info helped me, I hope it helps others. Any additional info would be appreciated.

I don't know who you talked to but the above is just not correct. The battery is a DC storage device and the inverter changes that DC voltage to AC voltage to run whatever is connected to it.
1. "A single battery is 700 amps"? Maybe on a submarine. The important number on the battery is Amp Hours, that's a rating of a load (12vdc amperage draw) over time. Most single dual use batteries (one's that say deep cycle/starting marine batteries) have very little AHs and list CC Amps (cold cranking amps) for starting an engine. The best 12 vdc true deep cycle battery (Group 24 to 27 & 31) is between 80 - 105 AHs until you get into very large case size and heavy weights.

2. The flooded cell battery (your average lead acid battery) should only be discharged down to around 50% of it's capacity. Going below that will do damage to the battery and shorten it's life while reducing it's capacity to hold a charge. With that being said, a "typical" group 24 marine battery will have 80 amp hours rating but only half of that is "usable". So if you have 40 amp hours of usable storage that means it can provide 40 amps for 1 hour.

[sandy43]

flybouy, I really don't know how to respond to your post. Batteries are not my thing, I'm learning. Perhaps the guy I talked to misunderstood me or I missed what he was saying. I thought I learned something, apparently not. So, you tell me how to figure this, layman's terms. I have 2 deep cycle marine batteries hooked to the inverter. Both relatively new showing 13.4 amps when charging. A Samsung residential fridge that draws 9-10 amps, most of the time. Nothing else is on, that I'm aware of, while driving down the road. How many hours will this last till I need to plug into AC power? I'm truthfully not being sarcastic, I really want to learn. Thanks

[Javi]

Driving down the road it will continuously charge your batteries off the alternator in the truck..

[flybouy]

Originally Posted by sandy43

flybouy, I really don't know how to respond to your post. Batteries are not my thing, I'm learning. Perhaps the guy I talked to misunderstood me or I missed what he was saying. I thought I learned something, apparently not. So, you tell me how to figure this, layman's terms. I have 2 deep cycle marine batteries hooked to the inverter. Both relatively new showing 13.4 amps when charging. A Samsung residential fridge that draws 9-10 amps, most of the time. Nothing else is on, that I'm aware of, while driving down the road. How many hours will this last till I need to plug into AC power? I'm truthfully not being sarcastic, I really want to learn. Thanks

As Javi stated, the tow vehicle should keep the batteries charged while under tow, given the load on the batteries don't exceed the charge vrate of the alternator and wire size.

When stopped, unplugged from the truck and shore power (i.e. batteries only) how long it will run the fridge depends on more information.

What are the capacities (Ah) of the batteries and are they 6v or 12v?
What is the size model of the inverter? I believe you listed that earlier.
Are there other loads on the battery when you run the fridge i.e. using the furnace, running the water pump, interior lights, etc.?
What's the average run time for the fridge? Do you mainly keep the door closed or do you have kids "grazing" frequently (opening the fridge door and just staring into it for minutes while they decide what they want)?

Not at all taken as sarcasm. Just trying to help and clarify. As you can see from the questions it's not a "one size fits all" type of answer as there are several variables that factor into the results. Keep asking questions, that's how we all learn.

[sandy43]

Ref charging, I know my Ford will charge while driving. I thought it charged the converter not the inverter. Apparently I was wrong. You say it charges both. Am I understanding that correctly?

My inverter batteries are 2 Interstate deep cycle 12V. Fridge door will be closed while driving and nothing else operating from the inverter. Either I'm driving or parked where AC is available. I don't boon dock, to old. No kids, all grown and gone, thankful. With what info I've given you, if I can get 8 good hours without AC and the fridge stay cold, I'll be a happy camper. Also, please don't forget to address the 1st paragraph. Solves lots of issues. Thanks

[flybouy]

Originally Posted by sandy43

Ref charging, I know my Ford will charge while driving. I thought it charged the converter not the inverter. Apparently I was wrong. You say it charges both. Am I understanding that correctly?

My inverter batteries are 2 Interstate deep cycle 12V. Fridge door will be closed while driving and nothing else operating from the inverter. Either I'm driving or parked where AC is available. I don't boon dock, to old. No kids, all grown and gone, thankful. With what info I've given you, if I can get 8 good hours without AC and the fridge stay cold, I'll be a happy camper. Also, please don't forget to address the 1st paragraph. Solves lots of issues. Thanks

No it charges neither, your truck will charge your trailer batteries while you drive. If you don't "dry camp" or boondock (camp with no 120vac power available then you have nothing to be concerned about. You can drive indefinitely and the truck will keep the trailer batteries charged and the inverter will continue to work.

[sandy43]

I miss stated that. I mint the inverter batteries, not the inverter itself. Sorry about that. So, the truck will charge the inverter batteries while driving. I did not know that. That's really good news. Problem solved. Thanks.

[travelin texans]

Originally Posted by sandy43

I miss stated that. I mint the inverter batteries, not the inverter itself. Sorry about that. So, the truck will charge the inverter batteries while driving. I did not know that. That's really good news. Problem solved. Thanks.

Your truck alternator charges the rv batteries that the invertor is connected to, just as shore power does when plugged in.

[sourdough]

Sandy, if yours is like mine you don't have an "inverter" battery unless they wired one specifically for the inverter. Upon purchase we discussed it but the way I use my trailer it wouldn't be beneficial. I suspect yours is the same. That said you would have the trailer batteries, a converter for the RV and a small inverter for the fridge. All are 12vdc.

Your 12vdc batteries, which power only small parasitic devices while traveling, are kept charged by your tow vehicle on the road. The converter is doing nothing. With a res fridge and inverter the inverter is drawing power from the batteries to power the fridge with 120VAC - the converter's only function in life in your case is to convert enough 12vdc current into 120vac to power the fridge. Unless modified it is a pretty small inverter (1K watts?).

120VAC is the other power system in the trailer. It is what is commonly used in regular S&B houses. It will power the AC, fridge, microwave, your AC outlets etc. AND your converter which then charges your batteries while you are parked and on commercial power (a generator can also provide that power). Those only work when you are plugged into commercial power. The rest of the time the only power coming into the trailer is 12vdc from the batteries which also power your lights.

Sort of long but sort of short when discussing the complex nature of how an RV is powered. Hopefully it sheds a little light on batteries, inverters and converters.

[Javi]

My Avalanche 313RS came with two series 24 batteries, one for the trailer and hydraulics and the other for the fridge inverter.

Both charge from the truck when hooked up and the motor is running, as well as off the converter/charger when on shore power and the inverter is in standby.

[sourdough]

Originally Posted by Javi

My Avalanche 313RS came with two series 24 batteries, one for the trailer and hydraulics and the other for the fridge inverter.

Both charge from the truck when hooked up and the motor is running, as well as off the converter/charger when on shore power and the inverter is in standby.

Javi is the inverter battery connected directly to the inverter and nothing else other than the converter? I thought about doing that with a 3rd battery but haven't gotten around to even delving into it - and really didn't want to take up any more room in the battery compartment.