Parasitic Battery Drain

[wyosteve]

Truck in my signature is completely stock. New batteries in April of 2021. This morning again, the batteries were too low to start the truck. Truck has sat for one week without driving. This has happened several times before when it sat for several weeks. What I'm wondering is if anyone knows what draws off the batteries while it sits and if there's something I can turn off to lessen the draw. I have that idiotic 8.4 radio which can't be turned off completely, just turn the volume down to '0'. I did have the headlight switch to the 'auto' position and wonder if that contributes.
I know I could drive it more often or use a battery tender, but that's not a good solution especially since when I use the truck/horse trailer for hunting, it may sit at the isolated trailhead for 2 weeks or more. Any insight or suggestions would be appreciated.

 

[SnoKing]

Truck in my signature is completely stock. New batteries in April of 2021. This morning again, the batteries were too low to start the truck. Truck has sat for one week without driving. This has happened several times before when it sat for several weeks. What I'm wondering is if anyone knows what draws off the batteries while it sits and if there's something I can turn off to lessen the draw. I have that idiotic 8.4 radio which can't be turned off completely, just turn the volume down to '0'. I did have the headlight switch to the 'auto' position and wonder if that contributes.
I know I could drive it more often or use a battery tender, but that's not a good solution especially since when I use the truck/horse trailer for hunting, it may sit at the isolated trailhead for 2 weeks or more. Any insight or suggestions would be appreciated.

You answered your own question, "radio"! Pull the radio fuse and see if batteries still drain.

 

[wyosteve]

Do the newer diesels have the same radio? If not, I might get rid of the '18 since I could get a good price for it with 31,700 miles. The radio in my '19 Power Wagon can be turned off.

 

[SnoKing]

Have you tried rebooting the radio?

How to Reset Uconnect®: Step-by-Step
Depending on which Uconnect® software version you’re running, the steps for how to reset Uconnect® might vary slightly. For the latest Uconnect® version 8.4, this is how you can perform a soft reset of the system:

1. Turn your key in the ignition to “Run,” but leave the car in park.
2. Simultaneously press the volume button and the tuner knob at the same time.
3. Continue pressing them down for 10 – 20 seconds.
4. After pressing the buttons for 10 – 20 seconds, the touchscreen display should flash the brand of your vehicle (FIAT, RAM, or Dodge), then proceed to go dark.
5. A few moments will pass with a dark screen, then the brand name should reappear. At this point, the Uconnect® system is reinitializing and will soon return you to the main Uconnect® screen.

Once you’ve completed these steps, your Uconnect® system should be running seamlessly once more! Keep in mind, these instructions are for a soft reset of Uconnect® version 8.4. They should resolve any issues with Bluetooth® connection, navigation, and small mishaps with the Uconnect® system without requiring you to entirely wipe the system of all the settings you’ve enabled thus far.

 

[Ozymandias]

Any non factory add ons to the truck, electric steps or so?

 

[wyosteve]

No sir. All stock. Original radio went bad about 2 yrs. ago and was replaced under warranty. But current radio works fine.

 

[petersonj]

New batteries in April of 2021. This morning again, the batteries were too low to start the truck. Truck has sat for one week without driving. This has happened several times before when it sat for several weeks.

How many times has this happened since the new batteries have been installed? If the answer is "two, or three, or more times", then these batteries could be well on their way in the sulfating process. If this is the case, no amount of parasitic draw diagnostics will help them.

Does this truck get driven short distances over a period of time (a month or two). If so, starter motor and grid heater consumption could override battery charging replenishment.

I have no experience as to what the maximum parasitic draw should be on a 2018 truck, but I imagine it would be less than 100 milliamps and more likely less than 50 milliamps (my '02 is maximum of 35 milliamps).

Testing for parasitic current draw on modern trucks can be a bit elusive as you need a multimeter capable of reading milliamps and a shunt to be placed in parallel to not to blow the fuse in multimeter. Even then you have to wait until all of the modules go to sleep for an accurate reading.

I think it would be worth your time to have both batteries independently load checked by a professional you trust.

- John

 

[wyosteve]

Thanks, this is the second time it's happened with the 'new' batteries. The first time was after it sat in the garage for a month and the batteries were totally dead. I suppose I could have a battery going out and I'll check that also.

 

[lpennock]

Flooded batteries hate going completely dead. AGM doesn't like it but will survive a couple times.

 

[petersonj]

Thanks, this is the second time it's happened with the 'new' batteries. The first time was after it sat in the garage for a month and the batteries were totally dead

I would definitely have the batteries checked. Also, there should be an IOD fuse (ignition off draw), or something like it, that can be lifted up without removal. You can use this feature when parking your truck for long periods of time. This feature will not allow power to electronic components that have a sleep mode. It will also disable under hood lights, interior lights, glove box lights, etc. Years ago, the factory provided this feature so that vehicles could be moved around on dealer lots without draining the batteries.

- John

 

[Topzide]

@wyosteve, for when the truck sits at a trail head while hunting (a bit jealous), you need to get a solar battery tender to plug into the power socket. Just make sure you have the fuse in correct position to allow power all the time which would allow the solar to keep batteries up. I've got one in my 1500 that doesn't get driven as much anymore and has kept the battery up in it. You could put a pretty good size setup on the horse trailer and back feed it through the 7 way plug. Should be able to offset the draw and keep them up.

 

[wyosteve]

Thanks Topzide, I hadn't thought of the solar tender route. Good idea. My other thought was to keep my small Honda generator in the truck so I could charge them when I got back to the trailhead, but that would seem to be an invitation to thieves!! The current batteries are AGM, but I just checked and the 'menu' says the voltage is less than 8v. So, I guess I'll try the new battery route tomorrow. Since these have gone completely dead once, it probably didn't help them. And today is our first cold (20's) day so with the grid heater draw, the batteries are likely not up to the task any longer. It might have just been my imagination, but it seemed like even this summer the starter turned a bit slower than I remembered so maybe the batteries were going. bad then already.

 

[Topzide]

@wyosteve, when I don't drive the 3500 for a couple of days, I back feed through the 7 way with my 4 amp tender. It's the new school type that varies the voltage up and down to help de-sulfate them. Make a great way to hook up since you don't need to open hood to hook it up. Also use Anderson Power Pole connectors about a foot from trailer plug so If I have to go quickly, they leg go without dragging anything out of the driveway! Ask me how I know.

 

[Timd32]

My '22 has the 8.4 but the software changes from year to year, so while it's an 8.4. Hard to say if they are the same as your '18.

The NOCO Genius chargers are pretty slick, they can do all sorts of types and they have a repair feature on them. They have adapters for various types if connections. I have a few NOCO Genius 5A and 10A, use them for a bunch of things. On power fail they will remember where they left off, but not sure how long that is actually for, so if you have a power hit and need it to auto come back there probably is a limit to that feature.

A bunch of us use them, I think anyway. I got them from posts on here. I just got from Amazon.

When you get sorted check them out might be a good fit, solar sounds slick as well.

I will need to figure out something for my 3500, if you do something 120VAC even thru the trailer plug, hang the cord somewhere you don't forget it, for me it would be a matter of time before I forgot and tool off with it plugged in.

But solar sounds good.

The charge from the 7pin is cool as well.

Hope you get it sorted.

 

[wyosteve]

Thanks much for all the responses. Heading to town for new batteries tomorrow. I also see Harbor Freight has a solar tender that has good reviews for not much money so will swing by there and pick one up to try as well. Will post on how it all turns out.

 

[lpennock]

If you are talking the 1.5 Watt from Harbor Freight, I wouldn't waste the money. It really isn't big enough to do much. Take a look at Renogy 10W Charger Maintainer. <https://www.renogy.com/10w-solar-battery-charger-and-maintainer/> It has a built in MPPT controller with makes it about 90% efficient Plus it knows when to switch from bulk to float mode.

 

[wyosteve]

Thanks lpennock, yes that’s the one I was looking at, but will check out the Renogy instead.

 

[Ozymandias]

Do you leave the key in the truck?

 

[wyosteve]

No didn't leave the key in. Learned that lesson a few years back on our Subaru!!

 

[Turbo Terry]

So what happens if you leave the key fob in the truck besides someone could steal your truck or car?