ESS again?!

[linuxos77]

We have a 2020 Wrangler 2.0T with 70k miles. Last summer (65k miles) ESS was warning amount needing service. I did the aux bypass (pulled fuse and its neutral cable) and replace the main H6 battery with an H7. All has been well until the dreaded service ESS came up on starting the Jeep this evening (earlier in the day it was fine and on a later start tonight it was fine… maybe just a fluke, there’s only maybe 5K miles on the new battery?. It was a short drive (3-5 miles) and when driving around battery voltage is at 13.9-14.1, when at a stop light it drops to 12.3 then 12.2/12.1 after a minute. Thoughts? Do the voltages in seeing seem right?

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[Heimkehr]

My personal standard is that the resting voltage of a healthy battery (i.e., when the engine isn't running) shouldn't be less than 12.3V.

That the voltage is dropping below that threshold, while the engine is running, strongly suggests that the battery requires replacement. Since it's less than 1 year old, possibly it was faulty, meaning you might have a legitimate warranty claim. It's also possible that there's a fault in the vehicle's charging system. That probably merits additional investigation to determine whether or not any such fault, if confirmed, was slowly damaging your current battery.

 

[linuxos77]

My personal standard is that the resting voltage of a healthy battery (i.e., when the engine isn't running) shouldn't be less than 12.3V.

That the voltage is dropping below that threshold, while the engine is running, strongly suggests that the battery requires replacement. Since it's less than 1 year old, possibly it was faulty, meaning you might have a legitimate warranty claim. It's also possible that there's a fault in the vehicle's charging system. That probably merits additional investigation to determine whether or not any such fault, if confirmed, was slowly damaging your current battery.

Yeah the quick drop from 12.3/.4 to .2/.1 caught my attention. It’s a Walmart Everstart with 3 year warranty, maybe I’ll make a claim and get it swapped. Of note, since the day I’ve had the battery the stereo (factory Alpine with sub and amp) makes a 1 second static hiss on ESS startup (especially when loud).

 

[linuxos77]

Of note after re reading your comment, while at a stop light with ESS working (ie engine is off) the battery voltage starts at 12.3/12.4 but after a minutes drops to 12.2/.1 then stays there it seems. For the second or two when the engine starts back up (taking foot off the brake) the voltage seems to flash to 11.8/.9 before going back to the upper 13v while engine is running.

 

[Heimkehr]

Of note after re reading your comment, while at a stop light with ESS working (ie engine is off) the battery voltage starts at 12.3/12.4 but after a minutes drops to 12.2/.1 then stays there it seems. For the second or two when the engine starts back up (taking foot off the brake) the voltage seems to flash to 11.8/.9 before going back to the upper 13v while engine is running.

That makes sense. You've isolated the ESS battery, meaning the primary 12V battery now assumes any and all electrical loads that the smaller battery would've taken on during ESS events.

I've used EverStart batteries, in no small part due to their value and Wal-Mart's rep for making the warranty exchange process easy. Let us know how things proceed here for you.

 

[ScotM]

Since you deleted the aux battery, and are still using the start stop, you may want to consider disabling the start stop feature. That will keep your new battery from doing more work than it was designed to do. A lot depends on how short your trips are and how often the start stop is active

 

[alphawolff]

We have a 2020 Wrangler 2.0T with 70k miles. Last summer (65k miles) ESS was warning amount needing service. I did the aux bypass (pulled fuse and its neutral cable) and replace the main H6 battery with an H7. All has been well until the dreaded service ESS came up on starting the Jeep this evening (earlier in the day it was fine and on a later start tonight it was fine… maybe just a fluke, there’s only maybe 5K miles on the new battery?. It was a short drive (3-5 miles) and when driving around battery voltage is at 13.9-14.1, when at a stop light it drops to 12.3 then 12.2/12.1 after a minute. Thoughts? Do the voltages in seeing seem right?

ESS messages can be a lot of things, not everything is related to the battery. It could be a simple hood switch, for example. It'll also throw an ESS warning for *pending* CELs that don't throw a CEL as it's just pending. You should get the vehicle scanned.

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