Tough battery question

[Overwatch]

Hi All,

I got help with a wiring issue here and now comes the big one. I have a 2021 392 (no ESS), and every morning my battery is almost dead. I came to the forum and did the following based on other threads: replaced my battery with an Odyssey Performance Series (1 year ago), took everything else off my battery except main cables and a battery tender I use every night, unplugged anything from cigarette lighters and USB plugs. When running the battery is at 14.1 Volts according to the off-road pages. Alternator seems fine...the Jeep doesn't die except when starting. I bought a battery jumper and it starts every time I have to use it. I have not checked every circuit for a parasitic drain, but it seems unlikely as the only things left were included with the Jeep which ran great for a year. I'm at the end of my rope....

Sponsored

 

[Dlit]

Parasitic drain does not need to be from aftermarket adding…for example vow Passats often see a drain from their amps. After 40k miles or so. I would methodically look for drain then one at a time add things back.

 

[Heimkehr]

+1 to what Dan said. I made the same conclusion before I got to the end of the OP's post.

@Overwatch
Chase each potential pathway, so to speak, individually and thus methodically. Take notes to keep track of what was investigated, and if anything was discovered that might be causative here. E.g., check every possible ground to ensure they are snug and secure.

From experience, diagnosing electrical issues is one of my least favorite things in the world. Best of luck. ?

 

[garyji]

How long does it sit?? Daily Driver??

G.

 

[Overwatch]

How long does it sit?? Daily Driver??

G.

It's my daily driver, never sits more than 24 hours. I'm just wondering if I'm missing something else.

 

[Heimkehr]

My '21, purchased new in late 2020, is also a daily driver. The original H6 continues to crank the engine as reliably as when the vehicle was new. I disabled ESS the day I drove the Jeep home. I'm not sure what effect, if any, that choice has on the practical service life of any primary battery in our Wranglers.

 

[garyji]

Dave, something is wrong to kill an Odyssey overnight.

G.

 

[Left Field]

It's my daily driver, never sits more than 24 hours. I'm just wondering if I'm missing something else.

Do you have a multi-meter or ammeter?
LF

 

[Old Jeeper]

Hi All,

I got help with a wiring issue here and now comes the big one. I have a 2021 392 (no ESS), and every morning my battery is almost dead. I came to the forum and did the following based on other threads: replaced my battery with an Odyssey Performance Series (1 year ago), took everything else off my battery except main cables and a battery tender I use every night, unplugged anything from cigarette lighters and USB plugs. When running the battery is at 14.1 Volts according to the off-road pages. Alternator seems fine...the Jeep doesn't die except when starting. I bought a battery jumper and it starts every time I have to use it. I have not checked every circuit for a parasitic drain, but it seems unlikely as the only things left were included with the Jeep which ran great for a year. I'm at the end of my rope....

Been down that road and got so far that the dealer was going to Lemon Law it. As we talking one of the mechs came over and said: Sir, Old Joe has worked here nearly 50 years and he is the only one who has not looked at it. Would you mind if I ask Old Joe to take a look? OK, I will give him 30 min if it's okay with (me) sure let him look I want to keep my car rather than Lemon Law.

15 min later Old Joe drives it up front and says it's fixed.

The switch (electric window) was installed improperly so the switch was HOT 100% of the time. So it died every night as a result.

2). Same thing happened to my '85. Ground wire was connected to the hot side and it died after a few days. I took it to 3 dealers and finally one found it and bingo, never again a dead battery. It was the Right rear Taillight stayed on all the time. I was single, and I never noticed it...

Here is what I would do: Disconnect your Primary Negative Cable from the negative post! See if your Jeep starts after the time it sits. If it does then disconnect the positive and leave the Negative on.

 

[DaltonGang]

Think simplicity first. Unhook the battery, and fully charge it. Let it sit for a couple of days, then hook it back up, and see if it cranks the engine over. If it wont crank, the battery is bad. Of it cranks, well, time to take it to an electrical expert and have them track the Gremlin down.

 

[Overwatch]

14+ volts means the ECU thinks the SOC of the battery is low and commands high output from the alternator.
The fully charged battery at near 100% the ECU thinks the battery is charged, thus the alternator output is reduced and you will see around 13.5 volts.

Charge your battery with a wall charger long enough to get it fully charged and report back.
It may take more than one day of charging even with your new battery. Do not use a high amp charger. 2 to 10 amps is good. I always use 2 amps overnight and all is fine.

Thanks Paul, I had no idea. I thought 14 meant it was all good. I'm charging it right now and will try it again in once the light on the charger is solid green.

Sponsored