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Old 08-31-2019, 08:56 PM   #1
Shackleton
 
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Default problem with Dometic cfx fridge OR solar power system?

Hi all. I have a problem to diagnose. My Dometic CFX 35w fridge has been increasingly erratic, but Iím not sure itís not actually a problem with my solar power system.

System details:
- 280W solar panel (new)
- 40A Renogy charge controller (new)
- 105AH OEC LiFePO4 battery (new)
- 12v outlets, no inverter, no other power source. A few LED lights and our top fan are the only other power draws.
- Itís been in use constantly for 5 1/2 months.

The issue:
The fridge worked great for about a month. Then, one very hot night in Big Bend National Park, it started doing this thing where the compressor would kick on every few minutes but just for 10 seconds or so and then stop. Fridge temp rose rapidly. Dometicís app didnít tell me there was a problem, and the fridgeís LEDs didnít blink warnings. But I switched the fridgeís battery protection cutoff to low and didnít have another problem for a while.

A couple months later, there was a similar glitch that I fixed by unplugging the fridge for a few minutes. Since then, the glitches have gradually become daily events. Sometimes now I do get a ďlow voltageĒ warning from the LEDs. But sometimes not. Sometimes the fridge just turns off. Sometimes it runs for ten seconds at a time. Sometimes it runs just for a second.

The glitches seem to happen mostly at night, but not always. Resetting no longer reliably fixes it. Right now, driving across Minnesota in the day, itís working great.

I havenít had a lot of opportunity to test the fridge on shore power, but the one time I did, it worked without a hitch.

Switching the fridge to emergency mode (turning off electrical control) usually works, at the risk of freezing everything, but once or twice itís failed there, too - the fridge just shuts off.

The Renogy charge controller, btw, says everythingís peachy. But thereís a lot of info in its bluetooth app that I donít understand.

The questions:
Is this definitely a fridge problem, or could there be a problem with my power system? A loose wire somewhere? A failing battery?

Secondly, if it is the fridge, how do I prove it? Itís under warranty, but I was told it had to be dead before I could trade it in.


Thanks, everyone.
Evan (Shackletonís the van)
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Old 08-31-2019, 09:41 PM   #2
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Default Re: problem with Dometic cfx fridge OR solar power system?

Quote:
Originally Posted by OrioN View Post
Your battery is running low. You solar setup is not supplying enough current to keep up with your demand or replenish the bank.

Connect the battery to your alternator so you can charge while driving.
Get more solar.
Get a shore charger and use when you can.
Maybe but I don’t think so. I ran a CFX80 in the Sprinter 24/7 for four years

205 watt solar panel 250ahr battery but never used more than 6% over night and unless dark and rainy days, always got back to 100%
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Old 08-31-2019, 09:47 PM   #3
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Default Re: problem with Dometic cfx fridge OR solar power system?

And I guess it could be that the battery is running low but the real problem is that the refer is fubar and drawing way more than it is supposed to
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Old 08-31-2019, 09:51 PM   #4
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Default Re: problem with Dometic cfx fridge OR solar power system?

Quote:
Originally Posted by richard cabesa View Post
Maybe but I donít think so. I ran a CFX80 in the Sprinter 24/7 for four years

205 watt solar panel 250ahr battery but never used more than 6% over night and unless dark and rainy days, always got back to 100%
Is solar your only charge source?
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Old 08-31-2019, 09:57 PM   #5
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Default Re: problem with Dometic cfx fridge OR solar power system?

Quote:
Originally Posted by OrioN View Post
Is solar your only charge source?
No, but day after day in the driveway it is

Could be plugged in but not

Could charge while driving but rarely (after 4 days in the trees on the Oregon coast)

His system should power that fridge without issue
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Old 08-31-2019, 10:03 PM   #6
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Default Re: problem with Dometic cfx fridge OR solar power system?

What is the voltage at the fridge when it tries to start up? Battery voltage?
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Old 08-31-2019, 11:23 PM   #7
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Default Re: problem with Dometic cfx fridge OR solar power system?

This is one of the reasons i have my fridge hanging off the LOAD terminals of my solar controller.

That way, you've got (in the controller) a way of monitoring/displaying the voltage and current that the LOAD is requesting/demanding/receiving.

I see that the Renogy 40A MPPT has load terminals. It's just a sequence of button-pushes to set them to "always on".

ControllerOnly.jpg

--dick (never too many meters)
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Old 09-01-2019, 12:04 AM   #8
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Default Re: problem with Dometic cfx fridge OR solar power system?

It still could be Shackleton’s solar. We don’t really know what “peachy” means

Any chance of a couple of screen shots of the Renogy Bluetooth app?
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Old 09-01-2019, 01:08 AM   #9
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Default Re: problem with Dometic cfx fridge OR solar power system?

A few common causes to check :
Battery may be never attaining a full charge by nightfall.
Too much volt drop to fridge, due to cable distance/ size between fridge and battery.
If using a cig. type plug, they can vibrate loose.
Once, had a situation where the female socket broke apart internally, causing intermittent operation.
Check any associated fuses, eg, fridge itself, inside cig plug, and at power source. Sometimes thermal type fuses can be flakey.
Changed my fridge connections to Anderson style plugs.
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Old 09-01-2019, 02:40 PM   #10
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Default Re: problem with Dometic cfx fridge OR solar power system?

Thanks, everybody, for the response so far.

To answer some questions:

Yes, solar is my only source of power.

By "peachy," I meant that I'm not getting any warnings from the charge controller, and the battery as reported by the controller never drops below 50%. It only gets anywhere close to 50% after a long night of starting the fridge over and over. An hour of good sunlight is usually enough to bring it back to 100%

The voltage at the fridge Ė according the the fridge's app Ė is usually 12+, then drops down to 10.8 or 10.7 as it starts up. BUT... last night I saw it drop to 9.6 before the fridge shut off. It's the first time I've seen that happen. The fridge's safety cutoff is 10.1. It didn't give me the warnings (blinking LEDs, app message), just shut off.

The controller has never shown the volts at the battery as lower than 12.

So...

If the fridge turning on is driving the voltage at the fridge below its cutoff value, how do I fix it?
And why has the problem become worse over time?

I'll attach screenshots of the Renogy app.
Attached Images
File Type: jpg direct_sun--emergency_mode.jpg (130.0 KB, 54 views)
File Type: jpg direct_sun--working--off.jpg (129.0 KB, 47 views)
File Type: jpg night--emergency_mode.jpg (128.0 KB, 47 views)
File Type: jpg night--glitchy--off.jpg (129.9 KB, 47 views)
File Type: jpg night--glitchy--on.jpg (130.3 KB, 47 views)
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