All,I just took delivery of a new Cardinal 5er. Came with residential Frigidaire Refrigerator, Label says 8.5amp draw The coach also was wired with a Xantrex 2000W ProWatt SW dedicated to powering the refridge(nothing else wired to it), connected to a pair of 6volt GC10 golf cart batteries. Unit is also prewired for a onboard generator for later. All 12v wiring is within 18" between batteries and inverter. We never dry camp, really the inverter is only used when on the road to maintain refridge/freezer temps. Fridge was precooled at home, when I left, I swatched the inverter on, and when disconnected from shore power, reefer continued to run. However, when we got to our destination 2 hours later, freezer had lost 10 degrees over two hours. Refridge maintained its temp. I suspect there are two separate compressors in this refridge.Reading the XAntrex manual, they talk about "exceptional" loads, including freezer compressors. I have to do a little more troubleshooting yet, to see if the inverter is not getting enough DC power to start the compressor spike, but they do go on to say that a larger battery might be needed?Dealer originally had two standard 12 volt batteries wired in parallel, but I told him I wanted a pair of 6 volt deep cycle wired in series.Whats the recommendation here? should I have stuck with the dual 12V in parallel?

What size wires are connecting the battery to the inverter? 18" is good but they still have to be fairly thick. It's probably drawing on the order of 90amps-12v.I would test at a site. Disconnect the shore power and see if the fridge kicks on if you turn the thermostat down. 10 degrees loss in an hour could imply it wasn't running at all and just functioning as a built in cooler. 8.5amps would be about 1000watts but typically getting a compressor to kick over takes 2-3 times the amps, so 2000watts would be marginal to get it started.

I think the best way to troubleshoot this is to try running the fridge on inverter at the house for several hours prior to taking a trip. This way you can watch things and see what is happening. I don't know about the Frigidaire but the Samsung RF18 has two compressors. The 8.5A draw on 110vac seems awfully high. You can roughly figure the DC amperage draw on the batteries as 10 times the AC current draw, so 8.5A AC would be around 85A DC on the batteries. I personally went with dual 12V batteries but yours should work. Experiment with it at the house and good luck.

valhalla360 wrote:What size wires are connecting the battery to the inverter? 18" is good but they still have to be fairly thick. It's probably drawing on the order of 90amps-12v.I would test at a site. Disconnect the shore power and see if the fridge kicks on if you turn the thermostat down. 10 degrees loss in an hour could imply it wasn't running at all and just functioning as a built in cooler. 8.5amps would be about 1000watts but typically getting a compressor to kick over takes 2-3 times the amps, so 2000watts would be marginal to get it started.1GA. My plan is to try that today at our current campsite today. Xantrex manual indicates that the inverter is good to 3000 watts surge, 1800 watts continous.

I wouldn't think you would have 2 compressors. Maybe the thermostat is located in the fridge only and the freezer just lost temp going down the road do to location and heat in the rig while traveling. I will be curious to see what you find out. Keep us informed.

What wire gauge was recommended from batteries to inverter in the inverter installation manual for your length wire run?1 Gauge is very likely too small.And pretty easy to check:Check voltage drop across the wires-- when someone starts the refrigerator, with a digital voltmeter check voltage between house battery positive and negative lugs.Check again at the inverter positive and negative lugs. Any delta between the two means resistance in the cabling. 2% drop is commonly recommended for primary circuits.While large gauge wire is not inexpensive, it is sure the least expensive "fix".

Inverter/Battery/load combination | Good Sam Community

gatorcq
Explorer
Jul 02, 2016
Our residential:
Rule of thumb - 1 amp AC = 10 Amps DC
Releasing ice can go as high as 2 - 5 amps AC. Remember the defrost cycle high current more time every 24 hours.
Ours will draw from 10 to over 25 amps DC.
Temps do not change
Our electrical system is capable of charging batteries Via, shore, generator or Alternator
Pure Sine wave Vs Modified Sine wave. Using MSW the refrig will work harder using more energy.
djousma
Explorer
Jul 02, 2016
MrWizard wrote:
That 8.5 amps had to be the max when the defrost heater is working
Not the compressor power use
I doubt the compressor even reached 300w aka 2.5 amps at 120v
My compressor fridge uses about 100w that's 9 amps into the inverter

FYI
ZERO is not cold for a freezer
Ice cream will be soft, maybe runny

This is 0F. Sorry I wasnt specific.
djousma
Explorer
Jul 02, 2016
dougrainer wrote:
Is it possible that the Freezer Door was NOT sealed tight. It may have slightly opened from driving? 11 degree jump in 2 hours from zero is a big jump when you consider the refer was NOT having its doors opened. IF your stationary test on Inverter shows no rise in temp in that 2 hours, you need to consider the doors not being latched correctly. Doug

I guess anything is possible, and maybe even likely, since the refridge side stayed at the set temp. I'll pay more attention to that. There are heavy elastics that go across the doors for travel, since like a typical new home unit, there are no latches.
djousma
Explorer
Jul 02, 2016
smkettner wrote:
djousma wrote:
My batteries were not dead when I arrived at the campsite, as the fridge was still operating, and I was able to lower landing gear, push slides out, etc before plugging in to shore power, so the batteries had to be maintained while driving too.

Not a battery or inverter issue. This is purely a fridge temperature control issue. Keep a watch but I think all is normal.

+11 seems like a lot but not unreasonable.

Does the freezer have an automatic ice maker that might be cycling?

Yes. I will be turning that off while travelling, since pump is off too, no ice to be made.
camperguy99
Explorer
Jul 01, 2016
Just open the door and when the interior lights come on the watts used doubles or tripples!
dougrainer
Nomad
Jul 01, 2016
Is it possible that the Freezer Door was NOT sealed tight. It may have slightly opened from driving? 11 degree jump in 2 hours from zero is a big jump when you consider the refer was NOT having its doors opened. IF your stationary test on Inverter shows no rise in temp in that 2 hours, you need to consider the doors not being latched correctly. Doug
Almot
Explorer III
Jul 01, 2016
You don't need more battery for what you are doing.

8A is when it's cycling, i.e. ~50% of time. After 2 hours on the road this amounts to mere 8 AH draw from your 225 AH bank. Startup current is higher but it only lasts a second.

Besides, you are getting 10A charge from the truck through 7-pin connector, and there is nothing else running except for maybe CO/propane detectors.

Your battery should be same full after those 2 hours unless you forgot to turn something else off.

Sounds like fridge/freezer issue.
MrWizard
Moderator
Jul 01, 2016
That 8.5 amps had to be the max when the defrost heater is working
Not the compressor power use
I doubt the compressor even reached 300w aka 2.5 amps at 120v
My compressor fridge uses about 100w that's 9 amps into the inverter

FYI
ZERO is not cold for a freezer
Ice cream will be soft, maybe runny
time2roll
Nomad
Jul 01, 2016
djousma wrote:
My batteries were not dead when I arrived at the campsite, as the fridge was still operating, and I was able to lower landing gear, push slides out, etc before plugging in to shore power, so the batteries had to be maintained while driving too.

Not a battery or inverter issue. This is purely a fridge temperature control issue. Keep a watch but I think all is normal.

+11 seems like a lot but not unreasonable.

Does the freezer have an automatic ice maker that might be cycling?
djousma
Explorer
Jul 01, 2016
Brett,

Thanks. Here is what Xantrex says:

With 1GA wire, at 1 foot, the drop is .0076V at 600watts, .0126V at 1000 watts, .0189V at 1500 watts, and .0378V at the full 3000 watts surge.

Contrast that with their maximum wiresize 4/0 its .0030, .0050, .0075, and .0150 per foot.

I am believing that the inverter is working fine, been running on it now for a couple hours, with no problems. I am leaning towards, either the connections were not tight enough - all were not right, and collectively, could have contributed to the problem, or just taking a residential refridge down the highway caused some problems.

I'll just have to keep an eye on things.