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We have a 2014 Jeep GC Ecodiesel. About two weeks ago, the vehicle would not start and the battery was dead (checked via multimeter). We jump started the battery and drove around for some errands. Next day, battery is dead again. Assuming the battery is bad (about 5.5. years in service), I get a new battery from Batteries + Bulbs. Swap out the battery and the following day, the jeep doesn't start. I thought maybe it was just a low state of charge, sitting on shelf or something, so we jump it again. This happens again after vehicle isn't driven for about two days. I have a Noco 7200 charger, so I charge the battery. Repeat this sort of back and forth over the next week. Frustrated I suspect it's a bad battery, and take it back to Batteries+. They checked in the car and get a strange result, show's good voltage but about 50% rated CCA (tested in car, under the hood test points). So I remove it from the vehicle, the charge it, let it sit over night (to ensure it holds a charge), and then test it the following day. Next day, it has 12.92V, puts out 909 CCA (rated 850), and pass the test with a load tester. So I plan to take it to dealer ship to find parasitic drain because I don't really want to or have the time to mess with hunting it down.
So I take to the dealer and explain it to the service adviser. He calls me today and says that it's a bad battery. They can't find anything until I replace/fix the battery @ $300. I ask if I replace the battery and it still tests bad, will they give me the money back because their diagnosis is incorrect. He says they can't do that. They tested the battery in the vehicle and get the following info: 50% rated CCA, measured volts: 12.97V, 1h13m charge time, and 12.1 Amp-hrs. It's a Grp 49 AGM battery. 12.1 Amp-hr looks really low (rated at 92 A-hr for 20hr). Service adviser just says, machine/test/technician tell me you need to replace the battery.

Would a parasitic drain/load impact a battery tester for the CCA/amp-hr results? (they have a GR8 battery testing unit) I tried asking any sort of technical question to him, but he said he doesn't know the details and yet they don't let the techs talk to customers because they might say something wrong. He's there to translate (but couldn't). Am I missing something? Other than take it somewhere else? Or try to figure it out myself? The service manager was gone for the day, but I'm going to call and talk with him tomorrow. I know to isolate possible suspects would be to remove the negative terminal, connect multimeter to measure current draw (50mA max expected), and then pull fuses to see what stops it. Any advice or troubleshooting would be great! TIA.
 

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2019 Jeep Grand Cherokee Trailhawk
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Maybe you're getting lower readings because the rest are being performed at the contact points inside the engine bay as opposed to directly on the battery. Battery could be fine and you could have another issue... how many are on the clock?
 

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Discussion Starter #3
Maybe you're getting lower readings because the rest are being performed at the contact points inside the engine bay as opposed to directly on the battery. Battery could be fine and you could have another issue... how many are on the clock?
Yes I think the battery is fine. I trusted the manager at Batteries+ who work before as a mechanic and could speak to battery chemistry, reactions, construction vs the service adviser who said the test device & his mechanic who did it said it's a bad battery (but can't explain a single thing about the basis or the troubleshooting reasoning). Only 52k miles on it.
 

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I assume the cable connections at the battery are clean and tight but it can't hurt to check the connections at the starter and ground.
And as odd as it may seem, check all cigarette lighter/accessory power outlets (front and rear) to be sure nothing is in the socket that shouldn't be that could cause the battery to drain.
 

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2011 WK2 Laredo and 2015 WK2 Laredo
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I am not the expert on this and take no responsibility for any damage, injury, or radiological contamination, but..... in addition to pulling each fuse, do the same for each relay, they can also be offenders (I might do the relays first). If none of the above identifies an offending circuit, pop off and replace, one at a time, the large cables to the computer box in the right front of the engine bay. Chrysler soldered relays into those logic boards, so one of those relays could be the problem child.

Option 2 is to take the vehicle to your trusted independent shop and pay them to make the diagnosis, and to document their findings in writing. Then take your documentation to a different, better dealer, and request your repair under warranty.

South Main Auto has some excellent videos on this procedure.

Best of luck, and keep us posted.
 

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From what you've said i don't think its a battery issue.
If it were my deal i'd pull out the ammeter to see what the amperage draw is.
Just make sure the engine is off, all doors closed including the hood and the hatch.

You said you know how to connect the amp meter in series with the battery and the Jeep's electrical system so i won't go into any detail on how.
Just be careful doing this, although auto battery voltage is not lethal its amperage capacity is enough to arc weld with.

50ma might be a typical quiescent draw for much older vehicles but these new vehicles with electronics typically will draw much more than 50ma. Maybe as much as up to 150ma (.15 Amps) or even a little higher.
Might want to do some research on this.

Whatever is going on to completely drain a new fully charged battery over night i'd think would be well over an Amp parasitic draw.
I'd start out by verifying the simple things first like:
Door sensors
Under hood light stays off when closed, if equipped
All cabin dome lights are off
All doors, hatch and hood fully close properly
Accessories
Anything plugged into USB ports, 120 AC outlets or cigar lighter sockets
(check with a flashlight there is no conductive debris in the cigar lighter socket)
Any user electronics like radar detector, dash cam, CB radio, USB cell chargers, etc.
Aftermarket module plugged into the OBD-II port

If all that pans out make sure there IS a parasitic draw thats either way out of tolerance or high enough to drain a battery.
Its possible there could be something else going on other than a parasitic draw issue.

If a high parasitic draw is verified then you have to roll up your sleeves to find the culprit trial and error by removing fuses and also relays one at a time. To speed up the process multiple fuses can be pulled but be careful each fuse goes back into their own socket.
Myself i would disconnect the battery, pull the fuse, reconnect the battery then take the parasitic draw reading.

A mechanic will basically do the same but charge you by the hour.
 

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Would a parasitic drain/load
Seems to me that if you were getting that much of a parasitic drain you (or your battery shop) would detect a very noticeable spark and electrical pop when they connected your battery cables.
 

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One thing i forgot is that a shorted or leaky alternator output diode is notorious for draining a battery in no time.
The alternator diode anodes are typically connected directly to the battery's + post.

A way to test is to either:
disconnect the alternator's output wire then put the ammeter in series with the alternator's + output terminal and its wire's output terminal
or
disconnect the battery then disconnect the alternator's output wire and leave it disconnected, reconnect the battery then let it sit over night and see what happens.
Might want to tape the wire to make sure its electrically isolated from engine and chassis ground.
Be careful with disconnecting that alternator's output wire making sure it does not touch the engine or chassis or you'll have 4th of July early.

While a leaky diode might not show up as an out of tolerance charging voltage, a shorted diode probably would.
 

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I just ran across this. See the attached video for a more advanced method of finding parasitic drain w/o disconnecting the battery or actually pulling fuses.
(Humble Mechanic).

Looks at millivolt level voltage drop across fuses when a parasitic drain is present. Much better than traditional methods.
 

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I just ran across this. See the attached video for a more advanced method of finding parasitic drain w/o disconnecting the battery or actually pulling fuses.
(Humble Mechanic).

Looks at millivolt level voltage drop across fuses when a parasitic drain is present. Much better than traditional methods.
Good find.
 
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