Both Batteries Dead

[LeodaJeep]

I'm wondering if I got a lemon JLUD. You may have read my other thread of suckee mileage. When I got it back from the dealership for that, they had found a bad cam sensor but also noted that it had "numerous" low voltage codes. They said the low voltage showed good now so they gave it back to me. After I got it back 3 weeks ago, last week I went on vacation to my daughter's house in Santa Barbara Ca., 180 miles each way. All was well until the morning after we arrived, when it wouldn't start and was deader than a door nail. Zip...nada. I had it towed to the nearest Jeep dealership, which may be the worst dealership in the country, Santa Barbara Jeep. They sell a number of brands including Maserati so my $60K Jeep was on the cheap side for them. I asked Abel, the service advisor if they might do me the favor of getting to it a little early because we were on vacation. He responded, "you too huh? Do you know how often I hear that...Thursday, Friday, Saturday, every day." I was shocked at the attitude. I have 6000 miles on the Jeep so it was warranty work that pays less than customer pay work. Maybe that explains a little of the attitude, or possibly it wasn't one of those fancy M cars that it would take 3 or 4 of my Jeeps to pay for.
But to my main point: At idle my voltmeter shows 12.6-12.7. As I accelerate it goes up to 13-13.6. When I let off the pedal, it goes to 14-14.4. It's almost like there is a short in the TPS (throttle position sensor). Letting off the pedal gets the highest voltage which makes no sense to me...or does it? To me, while running it should be 14 Volts + or is that not so on the Jeep JL?
How do your volt meters react to pedal position changes? What are your volts. I know it isn't an ammeter so maybe the voltage variance is normal? Please let me know as I don't want to get stranded...again. In Santa Barbara they replaced both batteries. Thank you for any help you can give. I already made an appointment but that is 12 days out and if this is normal I would love to cancel that appointment.

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[LarryB]

I'm wondering if I got a lemon JLUD. You may have read my other thread of suckee mileage. When I got it back from the dealership for that, they had found a bad cam sensor but also noted that it had "numerous" low voltage codes. They said the low voltage showed good now so they gave it back to me. After I got it back 3 weeks ago, last week I went on vacation to my daughter's house in Santa Barbara Ca., 180 miles each way. All was well until the morning after we arrived, when it wouldn't start and was deader than a door nail. Zip...nada. I had it towed to the nearest Jeep dealership, which may be the worst dealership in the country, Santa Barbara Jeep. They sell a number of brands including Maserati so my $60K Jeep was on the cheap side for them. I asked Abel, the service advisor if they might do me the favor of getting to it a little early because we were on vacation. He responded, "you too huh? Do you know how often I hear that...Thursday, Friday, Saturday, every day." I was shocked at the attitude. I have 6000 miles on the Jeep so it was warranty work that pays less than customer pay work. Maybe that explains a little of the attitude, or possibly it wasn't one of those fancy M cars that it would take 3 or 4 of my Jeeps to pay for.
But to my main point: At idle my voltmeter shows 12.6-12.7. As I accelerate it goes up to 13-13.6. When I let off the pedal, it goes to 14-14.4. It's almost like there is a short in the TPS (throttle position sensor). Letting off the pedal gets the highest voltage which makes no sense to me...or does it? To me, while running it should be 14 Volts + or is that not so on the Jeep JL?
How do your volt meters react to pedal position changes? What are your volts. I know it isn't an ammeter so maybe the voltage variance is normal? Please let me know as I don't want to get stranded...again. In Santa Barbara they replaced both batteries. Thank you for any help you can give. I already made an appointment but that is 12 days out and if this is normal I would love to cancel that appointment.

I am far from an expert, but I did have some issues with the batteries when I first bought my Jeep (used, 2.5 years old, sat a lot, which is bad for batteries):

- Does your ESS kick in when you are at a stop light consistently? If not, does it constantly show your ESS battery charging? I had this and they ended up replacing the main battery under warranty (I guess the main battery was causing the ESS battery not to charge up).
- Have you tried hooking it up to a trickle charger on your own? I bought one (Noco) and it charged the batteries for almost 9 hours the first time. I will use it once/twice a month if I am not driving a lot and it keeps the batteries charged up.
- what kind of driving do you do? If it is short trips with the AC blasting as an example, your alternator may not have a chance to get your batteries charged. Does it act any different after a good highway run?

I don’t spend a lot of time looking at my voltage gauge while driving, but it does get up to 14V on occasion, but often lower, especially if I have just charged up the battery.

 

[LeodaJeep]

I am far from an expert, but I did have some issues with the batteries when I first bought my Jeep (used, 2.5 years old, sat a lot, which is bad for batteries):

- Does your ESS kick in when you are at a stop light consistently? If not, does it constantly show your ESS battery charging? I had this and they ended up replacing the main battery under warranty (I guess the main battery was causing the ESS battery not to charge up).
- Have you tried hooking it up to a trickle charger on your own? I bought one (Noco) and it charged the batteries for almost 9 hours the first time. I will use it once/twice a month if I am not driving a lot and it keeps the batteries charged up.
- what kind of driving do you do? If it is short trips with the AC blasting as an example, your alternator may not have a chance to get your batteries charged. Does it act any different after a good highway run?

I don’t spend a lot of time looking at my voltage gauge while driving, but it does get up to 14V on occasion, but often lower, especially if I have just charged up the battery.

I was wondering if maybe they didn’t charge the two batteries when they replace them but since then I have about 400 miles of highway and is still jumping around on the voltmeter. Does your Jeep have a voltmeter that you can watch if it moves around like the numbers that I posted above?

 

[LarryB]

I was wondering if maybe they didn’t charge the two batteries when they replace them but since then I have about 400 miles of highway and is still jumping around on the voltmeter. Does your Jeep have a voltmeter that you can watch if it moves around like the numbers that I posted above?

It does have a voltage reading. I can try to keep an eye on it.

If you are able to go into ESS mode relatively quickly after starting your ride (in the summer, would be a matter of minutes), it would likely indicate that things are normal with both batteries. You can always just use a volt meter on the main battery to make sure it is getting back to normal range.

 

[LeodaJeep]

It does have a voltage reading. I can try to keep an eye on it.

If you are able to go into ESS mode relatively quickly after starting your ride (in the summer, would be a matter of minutes), it would likely indicate that things are normal with both batteries. You can always just use a volt meter on the main battery to make sure it is getting back to normal range.

 

[LeodaJeep]

I have a unit installed that keeps the ESS turned off. Maybe I should remove that it’s so every once in a while that battery gets used and recharged. What do you think of that?

 

[LarryB]

I have a unit installed that keeps the ESS turned off. Maybe I should remove that it’s so every once in a while that battery gets used and recharged. What do you think of that?

The reason why I had a battery failure early was because the previous owner didn’t drive it much (less than 8K miles in 2.5 years). If you do not ever use the aux battery, it will suffer a similar fate.

what I do is push the ESS off button upon starting, but if I get to what I know is a long light / rail crossing, I will engage it. I usually aim for 2-3 times a day …

As well, my dad religiously used a battery charger on his vehicles. He used to get extraordinary battery life out of them, and they would start on the coldest days (not a problem where you are, I know). Run it once/ twice a month if you don’t want to use ESS and that will help keep them fresh.

 

[LarryB]

I have a unit installed that keeps the ESS turned off. Maybe I should remove that it’s so every once in a while that battery gets used and recharged. What do you think of that?

By the way, this definitely played a factor in your batteries’ demise. If your aux battery went bad from lack of use, it very well could have led to an issue with the main battery, as they operate in parallel. It could have been something else, but this is a possible culprit.

 

[Reinen]

That's normal voltages you're seeing.
12.6-12.7v is a fully charged 12v battery. You're seeing more when you let off the accelerator because it's a smart charging system. The charging system avoids charging while you are accelerating to increase performance. You'll also see it fluctuate as the charging system will stop charging when the battery is full. Always throwing 14v at a full battery isn't good for it either.

 

[LeodaJeep]

That's normal voltages you're seeing.
12.6-12.7v is a fully charged 12v battery. You're seeing more when you let off the accelerator because it's a smart charging system. The charging system avoids charging while you are accelerating to increase performance. You'll also see it fluctuate as the charging system will stop charging when the battery is full. Always throwing 14v at a full battery isn't good for it either.

Have you watched your voltmeter do this same behavior? What you say makes total sense but I just don’t want to get stranded again. Do you think I am safe to cancel the dealership visit?

 

[LeodaJeep]

Have you watched your voltmeter do this same behavior? What you say makes total sense but I just don’t want to get stranded again. Do you think I am safe to cancel the dealership visit?
[/QUOT
I removed my ESS bypass…but actually pushing the ess button off does the very same thing. The way the bypass works is that whatever position you last had it set to, on a fresh start it goes to the same setting. If when I start the vehicle, I immediately press the Ess off, it would have the same affect on the battery, would it not?

 

[av8or]

That's normal voltages you're seeing.
12.6-12.7v is a fully charged 12v battery. You're seeing more when you let off the accelerator because it's a smart charging system. The charging system avoids charging while you are accelerating to increase performance. You'll also see it fluctuate as the charging system will stop charging when the battery is full. Always throwing 14v at a full battery isn't good for it either.

 

[Reinen]

Have you watched your voltmeter do this same behavior? What you say makes total sense but I just don’t want to get stranded again. Do you think I am safe to cancel the dealership visit?

I learned this because I saw my voltmeter do the exact same thing and determined why. It's normal. That isn't to say you don't have a problem, just that the voltages you're seeing are normal.

What @LeodaJeep said about the Jeep sitting idle too long is also correct. I WFH and my Jeep either sits all week or is only driven for a short errand or two (which is worse than sitting idle). Then driven on the weekends. I keep it on a battery tender because that's too long to let it sit without a long ride. There is a lot of parasitic draw in modern vehicles and they need to be driven regularly to avoid stressing the batteries.

 

[LeodaJeep]

I learned this because I saw my voltmeter do the exact same thing and determined why. It's normal. That isn't to say you don't have a problem, just that the voltages you're seeing are normal.

What @LeodaJeep said about the Jeep sitting idle too long is also correct. I WFH and my Jeep either sits all week or is only driven for a short errand or two (which is worse than sitting idle). Then driven on the weekends. I keep it on a battery tender because that's too long to let it sit without a long ride. There is a lot of parasitic draw in modern vehicles and they need to be driven regularly to avoid stressing the batteries.

Thank you

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