Fridge on battery

[unltd]

Newbie: Still getting used to this site and our new to us 2018 Newmar Ventana 4037. Getting ready for our first trip in this unit.


Anyone have experience with how long the house fridge will run off batteries alone? In other words, while not driving and without the generator running? 110v electric is it's only power source.

Thanks.

[Arch Hoagland]

How many batteries do you have?

[twinboat]

My guess is a 24 hour day before charging, if the batteries are any good.

That's a conservative # if you have 400 AH of battery. If you have 8 batteries, double that.

[Old-Biscuit]

Are you talking about the Inverter supplying 120VAC power to Fridge from the batteries?

Which Fridge ?
10 cu ft Norcold
12 cu ft Norcold
10 cu ft Frigidaire with the 2000W inverter and 2 extra batteries
19.7 cu ft Whirlpool with the 2000W inverter and 2 extra batteries

Different Options/different usage-run times

[dons2346]

The number of batteries is a useless number unless you know the amp hour rating of them.


If you have 400 amp hours of battery, figure using 50% of that.
I have gone 36 hours with zero power to the refer and everything temperature wise was still within safe limits and everything in the freezer was still frozen

[jacwjames]

If you can I'd recommend taking the time to do a test. I did this right after installing our RF18 Samsung residential.

Batteries were fully charged. Unplugged, turned on the inverter, turned the Samsung on and monitored the power over an 8 hour period. At the end I still had ~70% battery left so I knew I could easily go over night, which was my concern.



Last year on a trip and boon docking I'd run the generator for ~1.5 hour at night, sometimes less, until I had ~90% charge. Would easily last over night.

While driving my alternator charges the house batteries so when I'd stop I'd have full charge. Depending on timing I sometimes wouldn't have to run generator.

[AllegroD]

Originally Posted by Old-Biscuit

Are you talking about the Inverter supplying 120VAC power to Fridge from the batteries?

Which Fridge ?
10 cu ft Norcold
12 cu ft Norcold
10 cu ft Frigidaire with the 2000W inverter and 2 extra batteries
19.7 cu ft Whirlpool with the 2000W inverter and 2 extra batteries

Different Options/different usage-run times

Also need:
type/mfgr/model of batteries
Amp hour for each

# batteries
Inverter model

Originally Posted by jacwjames

If you can I'd recommend taking the time to do a test. I did this right after installing our RF18 Samsung residential.

Batteries were fully charged. Unplugged, turned on the inverter, turned the Samsung on and monitored the power over an 8 hour period. At the end I still had ~70% battery left so I knew I could easily go over night, which was my concern.



Last year on a trip and boon docking I'd run the generator for ~1.5 hour at night, sometimes less, until I had ~90% charge. Would easily last over night.

While driving my alternator charges the house batteries so when I'd stop I'd have full charge. Depending on timing I sometimes wouldn't have to run generator.

Great idea. The real way to determine what your setup can do. Also note ambient temperatures as well as if you will need additional items running.

[Gary RVRoamer]

Originally Posted by dons2346

The number of batteries is a useless number unless you know the amp hour rating of them.

Maybe not useless, but certainly not very accurate. If the battery size/type is unknown, 100 AH/battery will allow making a rough estimate, plus/minus about 20%. Sounds awful, but there are other usage factors that can make an equally large difference. It's a SWAG at best.

[JHinman]

I just checked the draw on my 10 cf Norcold. No lights or anything on, no truck hooked up, and my bitty little solar panel shaded, I was drawing 28 amps.

This was with a 3kw Victron Multiplus inverter.

[dons2346]

Originally Posted by JHinman

I just checked the draw on my 10 cf Norcold. No lights or anything on, no truck hooked up, and my bitty little solar panel shaded, I was drawing 28 amps.

This was with a 3kw Victron Multiplus inverter.

This was 28 amps DC or AC? Probably DC as it takes 10 amps DC to make 1 amp of AC. My Samsung uses 3 amps of AC so 30 amps of DC

[JHinman]

Yes, DC amps. Using lithium batteries my system is running about 13 volts DC.