Battery/electrical experts -- question on refrigerator

My default is 11 volts. That gives you some leeway when the compressor or any other load hits. At 12 volts my generator comes on too often.

Thanks for the info... just went over to the storage lot and checked on the temps... it was cold, didn't have my thermometer, but seemed really good after 4 hrs. The refer/compressor wasn't running, so it must have reached it's target temps of 0 in the freezer and 38 in the refer section. So, in the future, I'll start it up a few hours before hand instead of a day ahead. The battery meter showed that battery voltage had dropped about .2v from where it started this morning.

I have a small dorm fridge in my smaller toyhauler. Power is a pair of GC. Batteries run the frige on a MSW inverter, lights, furnace etc. When not running the furnace, I can usually go two full days before the batteries are at 50% SOC and I need to run the generator. That is with using interior lights when needed. And the dorm fridges aren't that energy efficient, how many WH/day it uses vs. a good fridge don't know. Fridge usually has about a 25% duty cycle, draws about 10Amps from the battery when running.

it's a residential fridge
you don't need 24 hrs to pre cool it
2 hrs maybe less it will be at operating temp
once you turn on a 120vac compressor fridge, the compressor runs until the fridge is cold
and it does not take long

want to run it overnight find.. no problem you have more than enough battery power

JoeH wrote:
Westend--- Thanks --- that gives me a guideline.... the only time I'll probably need to do that is when we are getting ready to go out on a trip and the MH is in the storage lot w/o electric so I need to start up the refer a day before hand. ?

I would turn it on a hour or two before leaving, it would be ice cold in that period of time. I wouldn't let it get below 12 volts. That's about 50% discharge. Just got done putting in a residential refrigerator in my 5th wheel. Its amazing how fast it will get cold. In my fridge it takes about 15 amp hours to cool down the from completely warm and only about a hour to do it.

JoeH wrote:
Westend--- Thanks --- that gives me a guideline.... the only time I'll probably need to do that is when we are getting ready to go out on a trip and the MH is in the storage lot w/o electric so I need to start up the refer a day before hand. ?

I would turn it on a hour or two before you it would be ice cold. I not let it get below 12 volts. That's about 50% discharge. Just got done putting in a residential refrigerator in my 5th wheel. Its amazing how fast it will get cold. In my fridge it takes about 15 amp hours to cool down the from complety warm and only about a hour to do it.

Westend--- Thanks --- that gives me a guideline.... the only time I'll probably need to do that is when we are getting ready to go out on a trip and the MH is in the storage lot w/o electric so I need to start up the refer a day before hand. With the old MH which was propane, not a big deal as long as we had propane... now, with the new one, it looks like a day in advance is doable with battery power without kicking in the genset.
The AGS defaults to start at 11.0 volts...... what would you recommend I set it to, if you think 11.0v is too low ?

Assuming a 220 AH rating for each battery, your total capacity would be 880 AH. The fridge draws 1.5 KWH/day, on average. That is 125 AH/day at 12v. With a target of 50% state of charge until recharging the batteries, you should be able to run the fridge 3 1/2 days. You will not want to wait until the batteries are at 11v because this will quickly ruin all your batteries.

The above math is not exact because you will also have the result of the Peukert effect on the constant draw from the batteries and the inverter loss so that 3 1/2 days may be down to 3 days in real-world use.

What else is turned on? How many amps solar are you getting? How hot is it inside the MH? How long has the refer been on? How full is it? How old are your batteries? How many amps does the inverter draw when waiting to invert? Based on average values to these questions... 32.63 hours:B
Why not unhook from shore power and find out?