I know there are variables involved here on the manufacturer of the fridge, battery etc... But for those of you that have one assuming the standard group 27 battery the dealer gives you - how long can you run that fridge on just the battery?

Our 2019 VanLeigh Vilano 320 has a Samsung residential fridge and Magnum 1k inverter. They draw approximately 160AHr per 24hr period. If you just have one standard lead-acid battery (85AHr) and only run it down to 50% before recharging (~12.0v, recommended if you want the battery to last very long), you will only get ~40AHr or 6hrs of running the refridgerator.Of course there are several variables, while driving your truck will supply a few AHr (mine does ~3A) which will add to your time, if you run lights, furnace, etc you will eat up some of that capacity, if your battery is not new or in good condition it won't provide the full charge, etc. Bottom line, you really should have at least 2 standard batteries just for campground to campground with a residential fridge in my opinion, the equivalent of 4 FLAs for overnighting, and at least 6 for much boondocking.I've added much larger batteries, and a whole-house inverter, to our 5er so that I can run everything and boondock for longer periods of time.

Ron did a great job of explaining the issues, except I would disagree on the boondocking recommendation. In Ron's example even 6 batteries would only keep the refrigerator running for a maximum of a day or so depending on other electrical use. Re-charging the battery bank would take a great many hours of generator run time. A large residential refrigerator is not practical unless you plan on hook ups at all times.

On any given residential fridge, the Energy Guide sticker will give you a good idea of how many KWH (and thus how many amp-hours) it uses per day.For example, this fridge uses 702 KWH per year, which would be around 1.9 KWH per day.1.9 KWH/day would drain around 158 amp-hours from a 12 volt battery per day:1900 WH/day / 12 volts = 158 AH/dayNote that the fridge will consume more than this amount on hot days, and less on cold days. It's just the yearly average amount.The inverter you use to convert 12VDC battery power to 120VAC will also waste some power, so you might actually need closer to 200 AH/day (on average) to power your fridge.Then you have to consider that lead-acid batteries shouldn't be frequently discharged beyond 50-80 percent, and now you need 240-400 AH of battery capacity.That's for 1 day of operation between battery recharges. If you can't completely recharge your battery every day, then you'll need more battery capacity to keep the fridge running until full recharge is possible.

JimK-NY wrote: Re-charging the battery bank would take a great many hours of generator run time. A large residential refrigerator is not practical unless you plan on hook ups at all times.Unless you add sufficient solar--in which case the costs for generator can be ignored.

austinjenna wrote:I know there are variables involved here on the manufacturer of the fridge, battery etc... But for those of you that have one assuming the standard group 27 battery the dealer gives you - how long can you run that fridge on just the battery?I thought dealers were installing 2 to 4 batteries with a compressor fridge/inverter.

Residential Fridge battery run time | Good Sam Community

austinjenna
Explorer
Apr 22, 2022

Absorption fridge takes a lot longer to cool. But if you freeze what you can, precool everything else before you load the fridge everything will be safe as the system will not need to cool as much

We do this now
JRscooby
Explorer II
Apr 22, 2022
austinjenna wrote:
The reason for my asking is my unit is in a storage yard and currently with my 3 way fridge I go the night before and start it up so its cold by the time I pick it up. I have no hookups at the storage yard.

But it seems the new units all have residential fridges in them and I was wondering about the run time on them as it seems it doesn't have the capacity to do the same routine as I currently do. I know I could always upgrade the battery bank.

My storage yard is only a few miles from my house so starting it up when I go get it only gives me about 10 minutes before I get it home which is not enough time for it to cool off.

We all know if I ask the dealer they will tell me it will run for a week LOL

Absorption fridge takes a lot longer to cool. But if you freeze what you can, precool everything else before you load the fridge everything will be safe as the system will not need to cool as much
austinjenna
Explorer
Apr 22, 2022
The reason for my asking is my unit is in a storage yard and currently with my 3 way fridge I go the night before and start it up so its cold by the time I pick it up. I have no hookups at the storage yard.

But it seems the new units all have residential fridges in them and I was wondering about the run time on them as it seems it doesn't have the capacity to do the same routine as I currently do. I know I could always upgrade the battery bank.

My storage yard is only a few miles from my house so starting it up when I go get it only gives me about 10 minutes before I get it home which is not enough time for it to cool off.

We all know if I ask the dealer they will tell me it will run for a week LOL
Wade44
Explorer
Apr 22, 2022
pianotuna wrote:
JimK-NY wrote:
Re-charging the battery bank would take a great many hours of generator run time. A large residential refrigerator is not practical unless you plan on hook ups at all times.

Unless you add sufficient solar--in which case the costs for generator can be ignored.

Except JimK may find it may be hard to get sufficient solar in NY.
pianotuna
Nomad III
Apr 22, 2022
Any battery of that capacity (~80 amp-hours), even my beloved SiO2 chemistry, is not going to be enough. Two 100 amp-hour batteries are probably not going to be enough. 300 amp-hours would be minimal. Recharging of a bank of that size in 4 hours would be about 1000 watts of panels.

A dc to DC charger would be useful for charging while trundling down the road.

I suggest using a kill-a-watt meter to actually measure the energy this fridge uses, per 24 hours.
theoldwizard1
Explorer II
Apr 22, 2022
Skibane wrote:

Then you have to consider that lead-acid batteries shouldn't be frequently discharged beyond 50-80 percent, and now you need 240-400 AH of battery capacity.

Coincidentally, that is about what you would get out of two 6V golf cart batteries. For maximum battery life, try not to go below 80 discharge.
Sandia_Man
Explorer II
Apr 21, 2022
It sounds like you just need to power fridge from home to campsite or to the next campsite, might be doable for a single group 27 (not the best battery for this scenario) although you will arrive with a pretty depleted battery, a 2nd battery would certainly help. You could travel with fridge off for a few hours, we've done so and had no issues as ice cubes and ice cream are still frozen upon arrival.

I did not try to read too much into your OP as there is no mention of extended or overnight use, which obviously would require a rather large investment in solar and batteries, and still would require usage of a genny and a fast charging converter or inverter charger when solar can't keep up. We do lots of RVing under adverse weather conditions and would not do so without a genny onboard.
time2roll
Nomad
Apr 21, 2022
I recommend 600+ watts solar if camping off-grid and expecting minimal generator use.
Probably 400+ ah of LFP batteries too.
JimK-NY
Explorer II
Apr 21, 2022
pianotuna wrote:
JimK-NY wrote:
Re-charging the battery bank would take a great many hours of generator run time. A large residential refrigerator is not practical unless you plan on hook ups at all times.

Unless you add sufficient solar--in which case the costs for generator can be ignored.

That would not work well either. I see you live in Regina at about 50 degrees north latitude. At this time of year a roof mounted 100 watt solar panel would put out a maximum of about 40 AH/day. For Ron's example of a 160 AH refrigerator, it would take 4 panels to break even assuming absolutely no clouds, no shade. It would probably take closer to 8 panels just to keep that refrigerator going in normal use.
time2roll
Nomad
Apr 21, 2022
austinjenna wrote:
I know there are variables involved here on the manufacturer of the fridge, battery etc... But for those of you that have one assuming the standard group 27 battery the dealer gives you - how long can you run that fridge on just the battery?
I thought dealers were installing 2 to 4 batteries with a compressor fridge/inverter.