Battery not keeping up with fridge - while running.

[Reinen]

Southern Utah can make fridges work overtime. They can easily run your batteries to zero (hence their voltage cutoff). I strongly recommend using a portable lithium battery instead of using the AGM batteries that you rely on to start & run the Jeep.

The lithium battery can handle being drawn low much better than AGM and it eliminates the possibility of making the Jeep inoperable or inducing early battery failure. Worst case scenario with the portable lithium battery, your fridge stops working. Sucks, but it's much better than the Jeep not working. The portable lithium battery also makes you free to set the voltage cutoff of the fridge to the lowest setting. The fridge will continue to run longer.

Just be sure to recharge the portable battery via an ignition switched power source (or solar), not the 12v in the rear if it's still set to always-on.

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[Robertyoke]

That rear plug has some serious voltage drop under load. I see 1 volt plus drop from the reading at the battery with a +/- 10 amp load. I cant even imagine the drop at the full 20 amp load rating.
I'd measure the voltage at the plug with the refer running and see just what you got rather than chasing a problem with charging system, that probably doesn't exist.

 

[Maverick909]

SO the best way to address this issues. I run a Jackery 500 in line. jeep charges just the Jackery and my Iceco JP50 Fridge runs off the Jackery power supply. I also tend to unplug the Jackery if parked over night currently so it doesn't kill the Jeep battery. This will change when i add the dual group 25 batteries in the near future. I haven't had the shut off problem since. I can make it two days pretty easy with out charging the Jackery running the Fridge at 37-39 degrees. For extend camp times I also have a 100W solar panel than will charge the power supply while the fridge runs.

Jackery 550 maH

 

[Left Field]

That reminds me - what IS a fully charged main battery? From my volt meter, I get a reading in the 12.8 range just sitting there, but the EVIC says 13.6 and above depending on when I take a reading.

12.6V - 12.8V are good readings for a fully charged battery when the vehicle is not running.

The charging system on our Jeeps is 'smart'. Or perhaps too clever by half What that means in practical terms is that the charging voltage can vary quite a bit, hence the good suggestion by @Fudster to watch the EVIC system voltage. It is common to see voltages between the mid-12's to the mid 14's.

The combination of the charging system being in a period of lower voltage along with the voltage drop from the small gauge 12V aux wiring could easily drop you below the refrigerator shutdown threshold, particularly during the higher current demand as the fridge starts.
To improve refrigerator operation, many people have put in a dedicated 12V outlet with heavier gauge wiring, for example:

A couple possible temporary workarounds:
1) If your fridge has an 'ECO' mode, that might reduce the current demand enough to maintain voltage. May not provide sufficient cooling however if it is hot outside.
2) Set the refrigerator low voltage shutdown feature to a lower voltage. That of course increase your risk of a no-start if the fridge draws down your battery.

LF

 

[JLR_AEV]

On a recent trip from Seattle to Moab, I had my Dometic 35 plugged into the rear cargo 12v port. Along the way, I noticed that the fridge had shut itself off since the voltage was below the threshold I had set (medium). I thought that since the Jeep was running, it would keep up with the fridge. What's the deal? Do I need to do anything different, or would a dedicated larger wire to the main battery be a better idea? Does the 12v plug run off the main battery or the aux battery?

Thanks!

Matthew

Dual batteries as @Maverick909 mentioned has been the way to go for me.
Not once have I regret buying the Genesis system and probably one of my favorite upgrade I have done to the Jeep.

I added their volt meter on the left which displays both the main and aux volt levels. I also added more charge ports which also had a volt meter integrated with it so now I leave the one on the left displayed with the AUX battery voltage and the right is the main battery voltage

 

[Blue Bear]

12.6V - 12.8V are good readings for a fully charged battery when the vehicle is not running.

The charging system on our Jeeps is 'smart'. Or perhaps too clever by half What that means in practical terms is that the charging voltage can vary quite a bit, hence the good suggestion by @Fudster to watch the EVIC system voltage. It is common to see voltages between the mid-12's to the mid 14's.

The combination of the charging system being in a period of lower voltage along with the voltage drop from the small gauge 12V aux wiring could easily drop you below the refrigerator shutdown threshold, particularly during the higher current demand as the fridge starts.
To improve refrigerator operation, many people have put in a dedicated 12V outlet with heavier gauge wiring, for example:

A couple possible temporary workarounds:
1) If your fridge has an 'ECO' mode, that might reduce the current demand enough to maintain voltage. May not provide sufficient cooling however if it is hot outside.
2) Set the refrigerator low voltage shutdown feature to a lower voltage. That of course increase your risk of a no-start if the fridge draws down your battery.

LF

Thanks for the info! I got a reading from the main battery last night after driving home. It read 13.1v. This morning it was 12.9v. The EVIC showed 14 to 14.1 this morning on the drive to work. I'm wondering if I have some parasitic draw from some things I put it. So, I've taken out fuses to see what happens over the next few days. I have an oil change next Sat. so I'm going to have the dealer test the system to see if they find anything weird. I wouldn't be so worried about all this if I hadn't just replaced both batteries last week!

 

[Left Field]

Thanks for the info! I got a reading from the main battery last night after driving home. It read 13.1v. This morning it was 12.9v. The EVIC showed 14 to 14.1 this morning on the drive to work.

As a battery comes off from being charged it is normal for it to drift down to its normal charge level (12.6 - 12.8). That would happen even with no load on it, parasitic or otherwise.

The voltage readings you've provided all look normal to me.

LF

 

[Sidewalk]

I occasionally run a fridge off the rear (I mainly leave the fridge in my van). There is a ton of voltage drop to the rear. I leave the fridge in the "low" voltage setting. I did a four day trip to southwest Utah a few weeks ago and didn't have any problems, but I did drive at least once a day (various mountain biking trails).

If it was something I was planning on doing a lot, I would run a separate battery (which I may still do) for the fridge (or other accessories). But it is going to be rare for me, so I might not for a while.

 

[Vrotfel]

I’ve had this fridge running for 3 years straight. I drive a lot… If I’m not going to be using the Jeep for more than a few days I plug in the battery to an extension cord and just slam it in the door.
I welded up a basic battery cradle with some scrap angle iron. It comes off with the top so it can be used with or with roof. ARB plug is connected to jeeps 12v w a quadratech splitter. 12v outlet is switched w key(inside fuse box optional)
Retracting cable keychain keeps wires outa slides.
best mod I have done, always cold drinks and snack.
Honestly I haven’t thought this much about it in years, it’s just always there and on.

( Jeeps been in SoCal and Florida all of that so outside temp doesn’t matter)

 

[Blue Bear]

Thanks, all. I'm going to have the dealership run a check of the charging system for peace of mind, but it sounds like I am OK. I appreciate all of you talking me down from the ledge.

 

[hoch]

I just ran down to So Utah last week. I’ve got the fridge plugged into a Jackery 500 (and the Jackery into the 12v in the back).

 

[Blue Bear]

I just ran down to So Utah last week. I’ve got the fridge plugged into a Jackery 500 (and the Jackery into the 12v in the back).

Were you at Arch Canyon?

 

[hoch]

Were you at Arch Canyon?

No, but I love that area. I was close to Capital Reef.

 

[trekster]

2022 JL Rubicon V6 eTorque. I’m running a Jackery 550 with an IceCo JP50/also Using the back 12 volt plug in the back. i plug the Jeep to JackRey, Jackery to frig. I noticed that the Jackery quit taking the charge from the Jeep with every start. Batteries are good. I checked the voltage when I start the Jeep, it temporarily drops 1 to 2 volts. The Jackery stops taking the charge, I’m guessing because of the voltage drop. if I unplug Jackery, start the Jeep then plug it in all is fine. To avoid needing to unplug the Jackery I’m going to try improving the wire to the 12 volt outlet to reduce the voltage drop. Maybe directly to the main battery. Any input would be greatly appreciated.

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