12v/battery/inverter/residential refrigerator

[spock123]

Originally Posted by lesptr

We did the Flying J overnight parking for a little sleep last weekend on the way to Myrtle Beach. We were parked for the overnight for no more than 7 hours total. Approximately 5 hours into the stay, I woke to visit the the little boys room and heard a barely perceptible beep. As I came around the corner, I heard the beep again and noticed the light on the propane detector was flashing red and that the temperature screen on the refrigerator was illuminated. The only gauge I have to monitor the batteries (at this time) is on the master panel. The batts were showing 1/3. This was our first attempt at dry camping and was a dismal failure. I really thought the batts would last through the night. Lights were used for no more than 20 minutes before bed and are LED.


Ok, now the details.
Coachmen Chaparral 336TSIK purchased in September 2016

2, 12 volt Interstate Batteries. (Batts are believed to be new at time of purchase)
[ATTACH]

Hisense Residential fridge.
(Forgot to take a pic of the spec page of the manual. Will do so if the folks think it is necessary)

Inverter
[ATTACH]

5r is plugged in to 50a service 24/7. All battery tending is done by converter which is WFCO. Not sure of the model.

Propane detector manual says light will flash red during the first 3 minutes after receiving power.

I'm sure there are different ways of correcting this.
2, six volt in series?
Better 12v batteries?
And others I'm sure.

Please keep in mind that I fly airplanes, am military trained i.e. Prefer one line bullet statements, and I'm getting old.
So DUMB IT DOWN FOR ME!


Fire away.

Thanks
L

A good place to learn about batteries and amps and how to hook them up is the 12 volt side of life part 1 and 2. I have a Whirlpool residential refrigerator and a 1000 watt inverter plus four six volt Trojans (T-105). The refrigerator will run off the batteries at home for four days. I took a short trip last week, about three hours and the inverter still read 12.8 when I unhooked the camper

[lesptr]

I've been reading and digesting that for the last couple of days. I think I'm going to go with 2 6 volts and see how it does. If I can't get a nap without running the batteries down too low to operate the refrigerator, I'll up it to 4. In order to go to four, I'd have to remove some stuff from that compartment.

[lesptr]

Originally Posted by pgandw

Before we can give sound advice, we need to know what your residential fridge really draws. Being a 120V appliance, there is a plate near where the cord goes into the unit that says how many watts and/or amps the fridge draws. If you know watts (say 160), divide by 110, then multiply by 10 to get your amps at 12V. If you know amps (say 1.35), just multiply by 10 to get amps at 12V. If my guess at 160 watts is correct - could be a lot more, I assumed a dorm-sized fridge - you are using 14.5AH, round up to 15AH for losses, for EVERY hour your fridge runs.

Two Group 24 Interstate batteries are 80AH each. To keep them above 50% charge (which probably will give you 200 charge/discharge cycles of battery life), you can use 80AH. That gives you 5 hours of run time for the fridge before the batteries are at 50%, with only 5AH available for everything else. If you go below 50% charge on your batteries, the number of charge/discharge cycles drops off rapidly.

To find out how your batteries are doing while towing, measure the voltage at the camper batteries with the fridge running AND the tow vehicle hooked up and running. Turn on the tow vehicle and camper running lights, too. If the voltage at the camper batteries is 13.2 are greater, the tow vehicle will keep the batteries charged. It probably won't add much charge, but will maintain. If the voltage is less than 13.2, the tow vehicle wiring can't keep up with the load.

My little A-frame fridge has a 160 watt DC coil - and it's continuous run with no thermostatic control. So when I am towing I am drawing about 13.5 amps (160/12). I do have 13.2 - 13.6 volts to the camper batteries with running lights and fridge on, and minivan running. So my tow vehicle wiring is good. I did replace my tail light bulbs with LED bulbs to reduce the load by a couple of amps. But the big thing - I absolutely must shut the fridge off of 12V before I disconnect the tow vehicle or set up camp. If I don't shut it off, I will significantly drain my batteries before I even get started camping.

Looking at the numbers, dry camping/boondocking with a residential fridge requires a generator or significant solar power (300 watts or better), and a good-sized battery bank (typically 4 batteries).

Fred W
2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time

I'm not able to pull the fridge out alone to check the plate where the cord attached, but this sticker is on the door.

[ATTACH]

[VinceU]

That nameplate is promising but most likely wrong. I quoted the 22 cuft unit in my motor home drawing 7.3 amps. I checked a friends 18 cuft box it draws 6.5 amps. Yours is 15 cu ft. , sorry to say the Chinese have not improved the fridge cycle by a factor of 5 (operates for near free) no way, realistically maybe 5+ amps multiply by 10 for D.C. Power

[CTGREG]

Will 4 12v true deep cycle batteries keep a residential French door fridge going all night while dry camping cross country?

[JCDMeyer]

Originally Posted by CTGREG

Will 4 12v true deep cycle batteries keep a residential French door fridge going all night while dry camping cross country?

https://www.batterystuff.com/kb/tool...-inverter.html

Considering that you only want to use 50% of the battery (or ruin the battery) I found a deep cycle battery that delivers 105 Ah (105 amps for one hour). 2 - 12 volt deep cycle batteries would probably power your fridge for 1 hour. However if you run a heavy wire from your tow vehicle alternator to a 1500 watt inverter you could power your fridge while you drive. It will depend on how many amps your alternator will put out. If your fridge requires 10 amps ac you'll need 110 amps dc from your alternator. I will assume that most vehicles big enough to pull a camper should have at least a 145 amp alternator. Of course the vehicle itself will make a draw on that power too.. (not sure how much) but if your driving at night with the air conditioner, lights, trailer lights, other accessories... You'll tax the alternator a bit. What I don't know is if a 145 amp alternator is enough.

Years ago I powered my fridge, computer, and a couple lights with a 1750 watt inverter hooked to my pickup truck (145 amp alternator). I burned 3/4 of a tank of gas so I switched to my lawn tractor and it worked.