Residential Fridge battery run time

willald wrote:
On the contrary, a residential fridge, when set up correctly with the right battery bank, an appropriate inverter to run it, and a generator to recharge when needed....Works very, very well for someone not planning to be near electrical hookups very much (boondocking).

^^^ This.

Grit dog wrote:
...Bottom line, resi fridge unless the camper is parked at a power source 99% of the time is an effort in futility...and warm beer and soggy freezer!

As one thats owned a total of 5 RVs over the course of last 22 years, 4 of which had absorption style frigs, the last of which has a residential refrigerator.....I have to respectfully disagree with this.

On the contrary, a residential fridge, when set up correctly with the right battery bank, an appropriate inverter to run it, and a generator to recharge when needed....Works very, very well for someone not planning to be near electrical hookups very much (boondocking).

As noted previously, I am able to run the frig up to 2 days without electrical hookup, off just batteries without ever cranking up the generator or burning any fuel. Run the generator for a few hours each day, I can run indefinitely, as long as the 80 gallon fuel tank holds up.

And, when I do finally need to refuel, I just need to get gasoline, not LP gas that can be more difficult to find. With an 80 gallon fuel tank, and the generator only using 1/2 gallon per hour maximum when running full power....I could camp for almost 2 months before we would need to break camp and refuel at all. I doubt that any RV with the older absorption style frig running on LP gas could go that long without refueling.

That doesn't sound to me like 'an effort in futility'. Sounds to me more like a very good setup for boondocking. I prefer this setup muuuch better over the previous RVs I had with the older absorption style refrigerator.

austinjenna wrote:
Thanks. I am not talking about boondocking or solar panels just simply starting the fridge for it to cool down before I bring it home to load up and head out.

It sounds like it will only run a couple of hours on 1 battery

Doubt you'll get a new camper with a residential fridge and 1 battery, but in general, OE power and a residential compressor fridge is still a poor combination.
I know you think you have just a specific short term situation that you will need to run off of an inverter, but it's quite possible that you're not considering all scenarios. You only travel an hour or 2? Charging while traveling? Run onboard genny or install a heavy duty dc dc charger?

Bottom line, resi fridge unless the camper is parked at a power source 99% of the time is an effort in futility...and warm beer and soggy freezer!

goducks10 wrote:
I would suggest upgrading your charger to a Progressive Dynamics that has the option to bulk charge anytime. Even if your batteries drop down 30-40% a standard WFCO won't bulk at more than 13.6-8. You waste a lot of time trying to quick charge at 13.6.

Not sure who this was directed to, but in my case, putting in a PD converter would be not only a huge down grade and not very smart, it would also be nearly impossible without redoing much of the electrical system.

Our RV has the Xantrex Freedom XC 2000 Inverter/charger unit. It provides really, really good multi-stage battery charging; Every bit as good if not better than what any PD converter would provide.

Although I do agree that for a lot of RVs, a Progressive Dynamics converter with multi-stage charging is a great upgrade over what it comes with from the factory. I did that upgrade on a previous RV we used to own.

I would suggest upgrading your charger to a Progressive Dynamics that has the option to bulk charge anytime. Even if your batteries drop down 30-40% a standard WFCO won't bulk at more than 13.6-8. You waste a lot of time trying to quick charge at 13.6.

MNRon wrote:
willald - I have a similar set-up (or had until switching to Lithiums a month ago). 630AHr AGMs, Magnum 1k inverter on Samsung residential fridge, also a Magnum 3k inverter with 125A charger for whole-house.

We found that our fridge alone would average 160AHr/24hr period. So if *nothing* else ran we could power the fridge for ~48 hours. I also am not adverse to running down to ~40% SOC once in a while. Practical experience with boondocking over a few years was that I didn't even think about battery capacity concerns if we plugged in every other night. When boondocking for a week or so I needed to average running the generator about 3hr/day, but didn't have to run it every day (but couldn't skip more than a day, and then needed to make up for the 3hr/day average).

Thanks, Ron, this is very helpful, and is probably very close to where I am. Will just plan on running the generator for a few hours most days when boondocking, and keep a close eye on charge levels. Will most likely work fine.

willald - I have a similar set-up (or had until switching to Lithiums a month ago). 630AHr AGMs, Magnum 1k inverter on Samsung residential fridge, also a Magnum 3k inverter with 125A charger for whole-house.

We found that our fridge alone would average 160AHr/24hr period. So if *nothing* else ran we could power the fridge for ~48 hours. I also am not adverse to running down to ~40% SOC once in a while. Practical experience with boondocking over a few years was that I didn't even think about battery capacity concerns if we plugged in every other night. When boondocking for a week or so I needed to average running the generator about 3hr/day, but didn't have to run it every day (but couldn't skip more than a day, and then needed to make up for the 3hr/day average).

time2roll wrote:
I frequently take cold food in a cooler out to storage. Load the absorption fridge and turn it on at the same time. And as soon as the rest is ready I roll. By the time the food might get slightly warm it is cooling down just fine. Never an issue.

Now if thinking about putting two cases of warm beer in there it may take a few days. Chilled food, frozen food is fine.

I tell my wife "honey, the more cold beer I add the better the fridge works. I'm saving our food"

;)

I frequently take cold food in a cooler out to storage. Load the absorption fridge and turn it on at the same time. And as soon as the rest is ready I roll. By the time the food might get slightly warm it is cooling down just fine. Never an issue.

Now if thinking about putting two cases of warm beer in there it may take a few days. Chilled food, frozen food is fine.

JimK-NY wrote:
...My thoughts and calculations show way less than 2 days. The 2.5 amps @ 120 is 25 amps @ 12 volts. You have 6 x 225 AH @ 6 volts which is 675 AH @ 12 volts. Draining battery bank to 50% gives you 338 AH @ 12 volts. 338/25 = 13.5 hours. Your inverter will cost you about 10% so somewhere around 12 hours. So you will need to fire up the generator about every 12 hours. You need to replenish 338 AH. If you have a good sized charger of about 50 amps that will take about 7 hours to reach a partial full charge. So 14 hours of generator time per day. Every few days you should consider running the generator full time for 24 hours to bring the batteries up to a full charge.

Of course this is based on the compressor running full time. Run time is a big variable and could be much less if the ambient temps are cool, no warm items are added and you don't open the door frequently or for long periods. I would not count on dropping below about 60% compressor run time. That would cut your gen time by several hours a day but probably no less than about 10 hours.

Thanks, JimK, for helping get more accurate numbers there. :)

Yes, if one assumes 100% compressor run time, and no more battery depletion than 50%, then about 12 hours is probably about right. Maybe less, depending on what other loads are put on the batteries.

I know the compressor run time for us is way lower than 100%, and I don't mind occasionally letting the batteries deplete a little below 50%. That being the case, I'm probably somewhere around 20-24 hours before we would have to run the generator some.

And, that is about what I expected for boondocking more than a day with this rig. We'll just plan on running the generator a few hours during the day to recharge the batteries. Depending on where we are, may well need the generator a good bit during the day anyway, so we could run the air conditioner and keep everything else cool, too.