Aux delete- Start/Stop still charging

[Devildoc22]

I have a 2020 2.0 JLU and my auxiliary battery has died every year. I was going to replace it myself this time since I am not under warranty, and I learned about the auxiliary battery delete instead. My main battery was just replaced last year, so I just disconnected the negative terminal for the aux battery and pulled the correct fuse. I read on here the ESS should still work, just off the main battery. I noticed it wasn’t today and still said it was charging. Is this common or did I do something wrong? I don’t care about the feature, I just want to make sure it is not going to try to drain my main battery still. My main battery is still showing 13.7-14.0 volts.

Sponsored

 

[THAW]

ESS is disabled when the JLs Intelligent Battery Sensor estimates the battery State Of Charge is
65% or lower.

Use an external AGM charger and/or drive more to recharge your battery. If charging doesn't re-enable ESS, you likely need a new battery.

 

[Terrymo]

Your alternator is charging at 13.7-14 volts.
With the engine off use a multimeter to test the voltage at the main battery terminals.

 

[Heimkehr]

My main battery is still showing 13.7-14.0 volts.

Add'l. context is required. Is that idle voltage during cold starts? Is that figure being observed (via the screen display) while the vehicle is being driven? Or other?

 

[Devildoc22]

Add'l. context is required. Is that idle voltage during cold starts? Is that figure being observed (via the screen display) while the vehicle is being driven? Or other?

Sorry, I was never taught about cars so I never knew a difference. I tested with multimeter cold as was suggested and it said 12.44 v

 

[Devildoc22]

Your alternator is charging at 13.7-14 volts.
With the engine off use a multimeter to test the voltage at the main battery terminals.

Thanks. This jeep is how I’m learning about cars by doing everything myself because I was never taught, so I did not know this. I used the multimeter on it cold and it read 12.44. From my further research after, looks like if I just charge it, it could possibly be fine.

 

[Terrymo]

Thanks. This jeep is how I’m learning about cars by doing everything myself because I was never taught, so I did not know this. I used the multimeter on it cold and it read 12.44. From my further research after, looks like if I just charge it, it could possibly be fine.

Good for you. There’s plenty I don’t know. Here’s a general chart for reference

 

[Heimkehr]

Sorry, I was never taught about cars so I never knew a difference. I tested with multimeter cold as was suggested and it said 12.44 v

If that figure represents the main battery's resting voltage, that's a fair reading by itself. "Resting" means the engine is off and hasn't been run for a good while, meaning there's no residual surface charge from the alternator remaining to obscure a truly accurate reading.

Now, resting voltage can appear OK, as yours does, and then fall off a cliff (thus possibly indicating a bad battery after all) during a cranking event. Connect your multimeter to the battery again and have someone start the engine. Record the voltage figure that the meter displays as the starter is turning the engine. Pay attention because it will occur quickly. Report back and we'll have add'l. required context to comment on the state of the battery.

It's good that you want to learn. We were all beginners at one time.

 

[Devildoc22]

If that figure represents the main battery's resting voltage, that's a fair reading by itself. "Resting" means the engine is off and hasn't been run for a good while, meaning there's no residual surface charge from the alternator remaining to obscure a truly accurate reading.

Now, resting voltage can appear OK, as yours does, and then fall off a cliff (thus possibly indicating a bad battery after all) during a cranking event. Connect your multimeter to the battery again and have someone start the engine. Record the voltage figure that the meter displays as the starter is turning the engine. Pay attention because it will occur quickly. Report back and we'll have add'l. required context to comment on the state of the battery.

It's good that you want to learn. We were all beginners at one time.

So after a night of rest instead of just 90 minutes, it read 12.14 cold and dropped to 9.6 when cranking. So I assume this means new main battery?

 

[lutey]

I have a 2020 2.0 JLU and my auxiliary battery has died every year. I was going to replace it myself this time since I am not under warranty, and I learned about the auxiliary battery delete instead. My main battery was just replaced last year, so I just disconnected the negative terminal for the aux battery and pulled the correct fuse. I read on here the ESS should still work, just off the main battery. I noticed it wasn’t today and still said it was charging. Is this common or did I do something wrong? I don’t care about the feature, I just want to make sure it is not going to try to drain my main battery still. My main battery is still showing 13.7-14.0 volts.

You need to check votage of battery while engine isn't running. If it's 12.4 or below.. the ESS won't work and it will say battery is charging

 

[Heimkehr]

So after a night of rest instead of just 90 minutes, it read 12.14 cold and dropped to 9.6 when cranking. So I assume this means new main battery?

That'd be my next move, yes.

 

[Bandit59]

I have a 2020 2.0 JLU and my auxiliary battery has died every year. I was going to replace it myself this time since I am not under warranty, and I learned about the auxiliary battery delete instead. My main battery was just replaced last year, so I just disconnected the negative terminal for the aux battery and pulled the correct fuse. I read on here the ESS should still work, just off the main battery. I noticed it wasn’t today and still said it was charging. Is this common or did I do something wrong? I don’t care about the feature, I just want to make sure it is not going to try to drain my main battery still. My main battery is still showing 13.7-14.0 volts.

Check volts with it not running and switch on

 

[Devildoc22]

That'd be my next move, yes.

Thank you so much for your help! I will definitely get a new one then.

 

[Heimkehr]

Thank you so much for your help! I will definitely get a new one then.

The larger and slightly stronger (in terms of cold cranking amps) H7 battery will fit, if your Jeep currently has the H6. If the latter, you just need to remove a press-fit spacer in the bottom of the battery tray to accommodate the larger H7.

Just be sure to use an AGM-type battery, no matter the size or brand that you choose.

I purchased my Interstate H7 AGM at Costco, saving significant $$ when compared to the battery price trends at Advance Auto and similar. Just an FYI.

A healthy 12V automotive battery should have a resting voltage no lower than 12.3V.

 

[Devildoc22]

The larger and slightly stronger (in terms of cold cranking amps) H7 battery will fit, if your Jeep currently has the H6. If the latter, you just need to remove a press-fit spacer in the bottom of the battery tray to accommodate the larger H7.

Just be sure to use an AGM-type battery, no matter the size or brand that you choose.

I purchased my Interstate H7 AGM at Costco, saving significant $$ when compared to the battery price trends at Advance Auto and similar. Just an FYI.

A healthy 12V automotive battery should have a resting voltage no lower than 12.3V.

I will definitely get the bigger one then. I’ll have to give Costco a call to see if they have it in stock. I saw a lot of people recommend Odyssey and I can get it for the same cost as the Duralast due to discount, but if Costco is cheaper I’ll do that.

Sponsored