When the fix is worse than the problem

[AndySpill]

A couple of recent posts on subject matter than touches upon the following really got me thinking about how, in my opinion, Stellantis dropped the ball on its dual AGM battery JL offerings.

Given the position, size, and relative difficulty, or at least awkwardness of changing out the Aux battery, there is no way that anyone is going to tell me that its placement in the vehicle was anything other than an afterthought: the opposite of considered design.

Although the true motivation for its appearance in such JLs can be debated, some arguing the need for many an owner to run aftermarket power hungry appliances during ESS events (perhaps unique to Wranglers and Broncos) that could rob a single battery of cranking power when the ESS event ends, what can't be debated is that the entertainment system Stellantis chose to equip its JLs with is voltage sensitive...too sensitive if you ask me. Stories of people running the ESS system on just the main battery seem to confirm that.

It would appear to me, given that plenty of other manufacturer's are running their ESS systems with one battery that Stellantis, when it discovered this problem should have sought out a more robust entertainment system, not introduce a solution (the Aux battery) to this voltage drop issue likely to cause at least as many problems as it solves. You don't position a component like this Aux battery, likely given its small size and need to be changed frequently, in such an out of the way place where its recommended procedure for replacement actually suggests that you break and replace vehicle components to get to it (fender pins.) And you don't put dissimilar size batteries, even of the same battery chemistry, in parallel.

That the aftermarket will devise better approaches (witness Genesis Offroad) is not a justification for a slipshod build.

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[Shibadog]

A couple of recent posts on subject matter than touches upon the following really got me thinking about how, in my opinion, Stellantis dropped the ball on its dual AGM battery JL offerings.

Given the position, size, and relative difficulty, or at least awkwardness of changing out the Aux battery, there is no way that anyone is going to tell me that its placement in the vehicle was anything other than an afterthought: the opposite of considered design.

Although the true motivation for its appearance in such JLs can be debated, some arguing the need for many an owner to run aftermarket power hungry appliances during ESS events (perhaps unique to Wranglers and Broncos) that could rob a single battery of cranking power when the ESS event ends, what can't be debated is that the entertainment system Stellantis chose to equip its JLs with is voltage sensitive...too sensitive if you ask me. Stories of people running the ESS system on just the main battery seem to confirm that.

It would appear to me, given that plenty of other manufacturer's are running their ESS systems with one battery that Stellantis, when it discovered this problem should have sought out a more robust entertainment system, not introduce a solution (the Aux battery) to this voltage drop issue likely to cause at least as many problems as it solves. You don't position a component like this Aux battery, likely given its small size and need to be changed frequently, in such an out of the way place where its recommended procedure for replacement actually suggests that you break and replace vehicle components to get to it (fender pins.) And you don't put dissimilar size batteries, even of the same battery chemistry, in parallel.

That the aftermarket will devise better approaches (witness Genesis Offroad) is not a justification for a slipshod build.

Exactly. Poor design all around.

 

[dsgrey]

I wondered this too after seeing many vehicles since my purchase in 2019 where they have ESS but only the primary battery. My son recently purchased a 2020 Honda with ESS and the single AGM battery is original so over 4 years old so I'd assume ESS isn't "hard" on batteries.

 

[PT's19Rubi]

At one time, the wife had a VW GTI with automatic (dual clutch) tranny, while I had the "R" with the 6 speed manual. The automatic had auto Stop/Start. The manual did not. The only visible difference was the automatic had a bigger battery (I think it also had beefier starter and alternator like the Jeep).
So, why didn't Jeep just put in a larger, higher capacity battery. There's a good 2 inches to spare between the fuse box and air box. A little redesign on the air box would result in even more space.

 

[Htfan]

A couple of recent posts on subject matter than touches upon the following really got me thinking about how, in my opinion, Stellantis dropped the ball on its dual AGM battery JL offerings.

Given the position, size, and relative difficulty, or at least awkwardness of changing out the Aux battery, there is no way that anyone is going to tell me that its placement in the vehicle was anything other than an afterthought: the opposite of considered design.

Although the true motivation for its appearance in such JLs can be debated, some arguing the need for many an owner to run aftermarket power hungry appliances during ESS events (perhaps unique to Wranglers and Broncos) that could rob a single battery of cranking power when the ESS event ends, what can't be debated is that the entertainment system Stellantis chose to equip its JLs with is voltage sensitive...too sensitive if you ask me. Stories of people running the ESS system on just the main battery seem to confirm that.

It would appear to me, given that plenty of other manufacturer's are running their ESS systems with one battery that Stellantis, when it discovered this problem should have sought out a more robust entertainment system, not introduce a solution (the Aux battery) to this voltage drop issue likely to cause at least as many problems as it solves. You don't position a component like this Aux battery, likely given its small size and need to be changed frequently, in such an out of the way place where its recommended procedure for replacement actually suggests that you break and replace vehicle components to get to it (fender pins.) And you don't put dissimilar size batteries, even of the same battery chemistry, in parallel.

That the aftermarket will devise better approaches (witness Genesis Offroad) is not a justification for a slipshod build.

First, I absolutely agree it's a terrible design.

However, I've been running the factory ESS dual battery system successfully for almost 6 years (2018 JLU) without issue. I've only had to change both batteries once DIY in that time. I also had the dealership install two new batteries shortly after purchasing because they were bad after sitting on their lot uncharged for weeks.

The DIY battery change is simple and quick going through the passenger fender to replace the Aux battery and then putting in a larger H7 battery in place of the smaller factory H6.

Note: the issue is their weak design of ESS requires the owner to have to "monitor" battery health. For example, if the dash voltage is constantly above 14v (alternator charging voltage) while driving with the accelerator engaged, the batteries are probably low and need charging. If it's not a daily driver, a battery trickle charger can be utilized to keep a healthy charge level. In other words, it's not a simple "drive and go" vehicle like other so called SUVs.

 

[AndySpill]

First, I absolutely agree it's a terrible design.

However, I've been running the factory ESS dual battery system successfully for almost 6 years (2018 JLU) without issue. I've only had to change both batteries once DIY in that time. I also had the dealership install two new batteries shortly after purchasing because they were bad after sitting on their lot uncharged for weeks.

The DIY battery change is simple and quick going through the passenger fender to replace the Aux battery and then putting in a larger H7 battery in place of the smaller factory H6.

Note: the issue is their weak design of ESS requires the owner to have to "monitor" battery health. For example, if the dash voltage is constantly above 14v (alternator charging voltage) while driving with the accelerator engaged, the batteries are probably low and need charging. If it's not a daily driver, a battery trickle charger can be utilized to keep a healthy charge level. In other words, it's not a simple "drive and go" vehicle like other so called SUVs.

Hey Jeff:

Curious...what are your driving habits? What I seek to know is if you tend to use your JL frequently, or at least take it on reasonably long highway trips that allow the alternator to provide more power than either battery needs to be topped off?

I'm an infrequently driver where Winter temperatures, unlike your "O Co," can get nippy and tax batteries.

 

[Htfan]

Hey Jeff:

Curious...what are your driving habits? What I seek to know is if you tend to use your JL frequently, or at least take it on reasonably long highway trips that allow the alternator to provide more power than either battery needs to be topped off?

I'm an infrequently driver where Winter temperatures, unlike your "O Co," can get nippy and tax batteries.

Hey Andy,

You are definitely asking the right questions. It has a lot to do with the JL "smart" alternator logic and our driving habits. I used to have a daily commute, but now work out of my home. So I'm using a battery maintainer if I'm not driving enough to charge my batteries.

This is where we can get into trouble by assuming the batteries are getting enough charge without monitoring/maintaining them from time to time. The JLs ESS design does a mediocre job at best by itself. Also many people misunderstand the dash voltage display. First of all, it is normal for it to be all over the map (12v to 14.5v) throughout a drive time/ESS event. This depends on many factors including if the accelerator or brake is engage etc. However, if it displays consistently above 14v ( while charging) then it probably senses low battery charge. Mine is normally in the mid 13s (charging) when the battery is in a healthy charged state.

 

[autotragic]

Hey Andy,

You are definitely asking the right questions. It has a lot to do with the JL "smart" alternator logic and our driving habits. I used to have a daily commute, but now work out of my home. So I'm using a battery maintainer if I'm not driving enough to charge my batteries.

This is where we can get into trouble by assuming the batteries are getting enough charge without monitoring/maintaining them from time to time. The JLs ESS design does a mediocre job at best by itself. Also many people misunderstand the dash voltage display. First of all, it is normal for it to be all over the map (12v to 14.5v) throughout a drive time/ESS event. This depends on many factors including if the accelerator or brake is engage etc. However, if it displays consistently above 14v ( while charging) then it probably senses low battery charge. Mine is normally in the mid 13s (charging) when the battery is in a healthy charged state.

One of the alternator companies now offers a replacement for the JL that doesn't have the stock clutch mechanism and let's the alternator run all the time instead of being computer-controlled. I've been wondering if that would solve a lot of the problems. Instead of letting the charging system do an almost adequate job just let the batteries charge like they always used to.

 

[Bill_BCNtoNY]

One of the alternator companies now offers a replacement for the JL that doesn't have the stock clutch mechanism and let's the alternator run all the time instead of being computer-controlled. I've been wondering if that would solve a lot of the problems. Instead of letting the charging system do an almost adequate job just let the batteries charge like they always used to.

interesting! If my alternator ever needs replaced I shall remember this!

 

[autotragic]

interesting! If my alternator ever needs replaced I shall remember this!

https://www.extremeterrain.com/powe...or-6-groove-pulley-250-amp-black-51024ws.html

That's the one I'm talking about that doesn't have the decoupler.

https://www.extremeterrain.com/powe...or-decoupler-pulley-250-amp-black-51024w.html

That's the stock style replacement with the decoupler so you can see the difference.

 

[Thofland-1]

I wondered this too after seeing many vehicles since my purchase in 2019 where they have ESS but only the primary battery. My son recently purchased a 2020 Honda with ESS and the single AGM battery is original so over 4 years old so I'd assume ESS isn't "hard" on batteries.

I have a 2019 jeep wrangler 2.0l 4 cylinder with etorque. I have AGM battery no auxiliary battery but I do have 48 volt battery pack with a motor and generator under the back drivers side seat. There also is no alternator on etorque vehicles.

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