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Old 08-21-2019, 09:36 AM
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Unhappy 2018 JKU Battery Issues

I have a 2018 JKU that I purchased in December of 2017. The vehicle is not my daily driver and sits in the garage un-driven for up to a week or two at a time on occasion, however more recently (since early spring 2019, it has been driven regularly on the weekends, seldom sitting for more than 3-4 days. Back in February of this year I had the factory radio replaced with a Kenwood DDX6705DS radio as well as a back-up camera installed.

For the first time this past December (after owning the jeep for just over a year, but before the new radio/camera), I went to start the vehicle and the battery was dead. I simply attributed this at the time to having left the door open and the dome light draining the battery as my wife was getting in and out of the backseat using the undriven jeep for Christmas present hiding/storage. So I jump started, drove and no more problems for another month or two, and then again after sitting for 5 days or so, dead battery. Again I jump started, assumed we left some door open, and didn’t think much of it. Then within another month, after only having not been driven for 3-4 days, dead battery again.

It seems now, that the battery is going dead (or too weak to start the vehicle, only a clicking noise) if being left for only 3-4 days. I had the battery tested at Autozone and they told me the battery was “good” and that I should slow charge it vs the rapid charge from the alternator. I’ve been doing this, but still, when undriven, and not kept on the battery charger for more than a few days – dead battery.

I’ve done a multimeter parasitic load test several times (both with the aftermarket radio on when shutting off the vehicle as well as powered off prior to shutting off the vehicle), and this test is consistently showing a parasitic draw of anywhere from 38-42 milliamps which for all the research I’ve done does not seem unreasonable or indicative of a problem. The voltage measurements after the battery tender goes from red to green show around 12.4 volts, but after sitting a day or two, can be down around 11.9 volts

I took the vehicle to the dealership for the routine service and asked them to check into this issue and provided them with all the information I had collected. Their response was as I expected “we can’t find anything; the problem is probably with the aftermarket radio and back-up camera” (aka GFY).

I have an appointment set up at the place where I had the radio/camera installed to have it looked at to see if it is an issue with the installation (they wanted to do this after I stopped and explained what was going on and what the dealership told me). But based on my repeated parasitic load tests showing a consistent ~40mA, I really don’t think the problem is with the radio.

Has anyone else experienced any similar issues? Are the factory installed batteries simply low quality? Can anyone recommend any other tests or things I should check to help find the problem? My gut feeling is I should be demanding a replacement battery from the dealership as I shouldn’t be having these problems with a vehicle that is less than 2 years old, but they are going to stick to the “it’s the aftermarket radio/backup camera” argument. Should I just replace the battery – and if so, are their any recommended batteries that would work better with the way I use the vehicle intermittently leaving it sit for days (possibly weeks) at a time?

Sorry for such a long post, trying to convey all the information I’ve got in hopes someone can offer some advice or information. Attached is a photograph of the battery info (this is all I could find/see)

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Old 08-21-2019, 11:00 AM   #2
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A fully charged 12 volt battery will be around 12.7v, they probably use the same garbage as they have for the last decade or more, recycled lead bottom of the barrel quality just to get it out of the door. Save yourself the trouble and buy an Odyssey agm or the like. Most any autopart store top of the line will be a high quality agm, dont buy optima they are junk to.

Also if you jumped it and never put a chager on it chances are its still not charged and that alone weakens it, an alternator is made to maintain mostly and isnt good to always be trying to charge a weak battery. Every once and awhile its good practice to throw a charger on it for awhile.

Might as well just upgrade it, good peace of mind!
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Old 08-21-2019, 05:57 PM   #3
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How is the radio connected? Does it have a can bus adapter on it (pac or Maestro)?
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Old 08-21-2019, 06:16 PM   #4
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Google: How to measure the parasitic battery drain

Likely it's the head unit drawing power, I went through this on my black 09 and had to make some minor changes to the wiring. My 2018 JKU will set for several days as well, and with my ILX F309 and Maestro it doesn't draw the battery down.
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Old 08-28-2019, 10:22 AM   #5
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I just replaced my battery and have had several abuses to it before hand. It's a 2014 but only has 35k miles on it. I have left a light on, like you did and it sat for a long time. I later found the garbage battery terminals that Chrysler uses just rocking back and fourth. The radio, lights, everything worked, but I hit the starter and nothing. Putting an allen wrench in there for a check made it work. So I replaced the OEM terminals with some $3 Auto Zone ones that tighten down just fine. Finally, the battery died. Luckily, in my garage, so I was able to replace it without any drama. But it went from "just fine" one day to dead the next morning.
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Old 08-28-2019, 10:31 AM   #6
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Is the camera connected directly to the battery instead of through a switched source?
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Old 09-03-2019, 01:19 PM
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The camera is connected directly to the radio to the best of my knowlege (I had it installed at a shop that does radios/cameras, etc. I'm taking it back the place I had the radio/camera installed to have them look it over, but I suspect they will find nothing wrong with the installation. Like I mentioned in my original post, the parasitic loads (which I've tested MANY times) are negligible ~ 40 milliamps; and the battery voltage after sitting on the charger drops to below 12V (from a max charge of around 12.4) overnight. I'll simply be replacing the battery with an AGM type as was suggested in the first response to my post. Now I'm just trying to determine what size battery to get - as I see some websites/manufacturer's call for a "size 34", and others call for a "size H6" - both of which appear to be *almost* the same size.
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Old 09-08-2019, 12:09 PM   #8
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Do you have any accessories on your rig? If so do you have the negative attached to the top of the negative terminal?
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Old 09-08-2019, 12:33 PM   #9
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Originally Posted by demyer View Post
(...) Now I'm just trying to determine what size battery to get - as I see some websites/manufacturer's call for a "size 34", and others call for a "size H6" - both of which appear to be *almost* the same size.
34R or H6
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Old 09-08-2019, 01:28 PM   #10
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Originally Posted by cdeslandes View Post
34R or H6

You are correct and many of the online sources are wrong. My TJ has a Group 34 battery in it as a known quantity. The positive post is on the left as you look at the side closest to the posts. The battery in my 2017 on the other hand has the positive post on the right. Measuring the length of the batteries, they are both 10 1/4" long, which makes the JKU battery a 34R. (The R means the post locations are reversed).
None of the online sites I looked at (O'Reilly, NAPA and Batter Source) calls for a 34R (two called for a 48 and one called for a 34).

For reference for the members and especially the OP, a Group 48 battery is a little over 12" in length and a group 34/34R batter is a little over 10" in length. Neither my TJ or JKU will take a 48 as there is just not enough room. Also the label on my 2017 is the same as the one posted by the OP.

OP - while many will immediately jump on the AGM wagon, it is not necessary to spend that kind of money for a decent battery. In fact you should be able to postpone the purchase for a bit. You mentioned the battery tender, yet from you post it seems that once it reaches the green light you disconnect it. That is not how a battery tender is designed to be used. It is designed to be left hooked to the battery when the vehicle is not in use. It maintains the charge or "tends" to the charge. It is more of a slow trickle charger that keeps a battery at its prime.

Since you are not using the Jeep as a DD, I would just keep the battery tender hooked up and see how the battery performs. If the tender won't maintain the battery, then call around for a decent price on a standard battery and let them match what's in the Jeep. The Group 34 that is in my TJ was purchased from a local (South East US market) battery company for $120 last year (currently the are $130) and has 1000 CCA which is a lot more than the factory battery.

Modern Jeeps do have a fair amount of parasitic draw, not only your entertainment unit, but the the instrument cluster as well. At least on the TJ when my battery is disconnected I lost the trip mileage. Most modern "radios" have to hot leads, one that is connected to the battery to maintain the memory and the other to the ignition switch to turn it on or off.

And of course if you have the remote lock/unlock that is always on and if you have remote start that is always on as well.
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Old 09-08-2019, 07:32 PM   #11
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I had issues and all it was the cable clamp not getting a good connection on the battery post. The battery post seems small compared to the clamp. The clamp was tightened down as much as it would go but would still move / wiggle . I ended up putting a new clamp on the end of the positive cable . No issue since.

Before two trips to the shop and messing around with battery chargers.
Sport JKU 3.73 anvil /black .
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Old 09-09-2019, 08:32 AM
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Thanks for the feedback everyone. I was aware that it is a 34R with the positive terminal on the right side, but wanted to be sure either a 34R or H6 will drop into place. I've been looking at the Odyssey batteries, but can't find a place to directly purchase, so I would have to order online, and certainly don't want to spend that kind of money to find out it won't fit and can't be returned. I realize I probably don't need to spend $300 on a top of the line AGM battery, but come this fall I will be using the Jeep for hunting season here in PA where they open seasonal roads and I don't want to be 4-5 miles back a seasonal road with 6" of snow, and come back at the end of hunting all day to find the jeep won't start - especially since it has started having these issues. I've purchased one of those portable jump starters (so I've already got over $100 sunk into that) - but I just want to have absolute confidence that the Jeep will start without fail after sitting in below freezing weather all day - and right now I have no confidence whatsoever. It seems crazy to have spent $40K on a Jeep only to ask my Dad to drive his Toyota Forerunner when we go hunting because I'm afraid the jeep won't start and will leave us stranded!
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Old 09-09-2019, 09:24 AM   #13
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Before buying a battery, I would take MW2016's advice and do a parasitic battery drain check. It can be done in your driveway with a $20 multi meter purchased from Harbor freight. https://www.harborfreight.com/electr...ity-61593.html

A new battery might solve your problem, but if there is a parasitic draw taking place, then the new battery will die just as fast and you'll be back where you started.
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Old 09-09-2019, 10:35 AM   #14
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No one ever mentions the BLUETOOTH MODULE. It is hidden behind the HVAC controls and if it does not have the stock head unit installed, it goes into constant search and will drain the battery in a few days. I had this exact issue after upgrading my head unit until I unplugged that POS. Removing it will take no more then 10 minutes and its another piece of the puzzle.

P.S. I am sure you know, but the jeep computer doesn't go into true "sleep mode" until a bit of time has elapsed, locked, without the hood open ( or the hood open button pressed down with tape)
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Old 09-09-2019, 01:10 PM   #15
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One word about Odyssey batteries: their posts are on the smaller size, and the OEM negative terminal doesn't grip well on it. If getting one, think about upgrading the negative clamp (not a bad idea anyway)
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Old 11-19-2019, 08:24 AM
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I took the Jeep back to the place that had installed the radio (Kenwood DDX6705) and they put the old one back in and went through some whole procedure of shutting down the old one in a certain way, letting everything go to sleep and so forth that supposedly was required by the Kenwood installation folks (he called and spoke to them directly about this issue). But he did not remove the "bluetooth module (as you've referred to it). I was good for a couple of months, then in the last few weeks it's died after only a few days of sitting idle for two weeks in a row. I'm really thinking it is this UCONNECT/Bluetooth module. Does this thing do anything at all that it would still be needed? I've found in installation literature from other radio mfgs that this exact problem could be occurring (see page 11 of https://insaneaudio.com/wp-content/u...ps_current.pdf ). I can't seem to find any other discussions about this on this forum or elsewhere on the internet though. Surely I can't be the only one that has had this problem.
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Old 11-19-2019, 09:33 AM   #17
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Pull the fuses for the aftermarket radio and camera, if the 40ma draw stops you know that's the problem.

Just letting the alternator charge the battery after it's been jumped is not the greatest. Your going to kill the battery early with repeated discharges.

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