Auto start stop question

[Chunky White]

I bought my JTR used with 61k miles and the start stop worked for a few weeks then stopped. I figured that was because i sit in the JTR at lunch and before work with it in acc which drains the battery some. I had it serviced today and the start stop starting working as soon as I left the dealership. Could they have charged the battery while it was in the back getting serviced or reset something that would cause it to start working again? I dislike the feature and have always turned it off on all vehicles with it but thought it was crazy that it now works. Maybe the 2 hours of four wheeling in low range charged it back up. I travelled for work about a month ago and drove three hours there and back and it did not work then so i do not know

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[Max-t]

Everyone thinks it takes weeks to charge up the battery and that it drains down in seconds. Not the case. It’s all hooked together all the time. Just like when you jump start your car and drive home… the battery is all charged up.
That said, Italian batteries, and frankly all batteries lately, are junk. The sbs is prone to failure.
mid they did anything, they likely wanted to get paid for it so it would be on your RO.

as to why it suddenly started working? Maybe they turned off the AC? Noticed a fuse? There’s so many things that tie into the Ess it’s a bit of a tough nut to diag.

 

[Chunky White]

Everyone thinks it takes weeks to charge up the battery and that it drains down in seconds. Not the case. It’s all hooked together all the time. Just like when you jump start your car and drive home… the battery is all charged up.
That said, Italian batteries, and frankly all batteries lately, are junk. The sbs is prone to failure.
mid they did anything, they likely wanted to get paid for it so it would be on your RO.

as to why it suddenly started working? Maybe they turned off the AC? Noticed a fuse? There’s so many things that tie into the Ess it’s a bit of a tough nut to diag.

It was a free service at a Honda dealership of all places. Well I am sure I could find the service added to the bill of sale if I looked hard enough but it cost nothing today. I just thought it was crazy that I had driven the JTR for 5-6 months without it working and it started working again as soon as I left with it today.

 

[Max-t]

No not you… the technician wants to get paid. 99.7% of shops work piece rate… as it were. Ya spend all day running back and forth to the service writer or foreman… “I need a change fuse added”. “I need another 1/4 diag”. Etc. it all gets itemized.
it basically means you get crappy service from your technician, cuz ya don’t get paid to do it right, just to do it. Most of the good techs left for small joints or to do their own thing.
Come-backs and satisfaction surveys fall on the service writers bonuses.

but, I suppose not all places give you an exact copy of the RO. Could be a simplified customer copy. After my shop went that way, I quit that career and haven’t been back too often but for a short stint as a Service writer at Toyota.

 

[Lunentucker]

It only works if certain conditions are met. If it's too hot (ambient) it won't work. Same with too cold.
They may have charged the batteries. If it's 21 or older and still has the original batteries, then it's probably time to replace them both or disconnect the AUX altogether and replace the main with a fresh AGM.

 

[ShadowsPapa]

Just like when you jump start your car and drive home… the battery is all charged up.

Seriously? How long you been in auto electric business?
Takes a long time to actually reach SoC of 100%.
You can't jump it, drive 30 minutes and have a fully charged battery - period.
Sorry, gotta laugh. It takes hours to charge a battery that's sitting at 12.2-12.4 volts.


At 20 amps it takes mine about 4-5 hours to reach 100% SoC from 12.4 volts. So no one can tell me jump starting a vehicle then driving it home gives you a fully charged AGM battery. That's bunk.
The last 10-15% is the most difficult and takes the longest!
And unless you are running 14.5 volts for a long period of time you aren't charging anywhere near that rate.
the math doesn't work out.

Maybe the 2 hours of four wheeling in low range charged it back up. I travelled for work about a month ago and drove three hours there and back and it did not work then so i do not know

All it would take is to make it get to over 12.4 volts or so. So 2 hours of non-idle RPM driving could hve easily done it.

There's a lot of factors, including the cat temps and other things these track.
But you can operate just fine in a voltage of 12.2 for starting and driving but not be enough for the ESS to function.
Check my dozens of posts in other threads on these batteries, what it takes to charge them, the various state of charge issues and more.

I've got a fair thread from over a year ago on tracking the voltages, how long it took to reach various states of charge, the rates needed, when ESS will work or not work, the voltage at which the aux switches stop working and more.

I have a chart posted here in a couple of places that shows the percentage of state of charge associated with various battery voltages for AGM batteries.

 

[Chunky White]

It only works if certain conditions are met. If it's too hot (ambient) it won't work. Same with too cold.
They may have charged the batteries. If it's 21 or older and still has the original batteries, then it's probably time to replace them both or disconnect the AUX altogether and replace the main with a fresh AGM.

It is a 2020 so I should probably check and see what the date is on the batteries. I have no idea whether they are new or not

 

[ShadowsPapa]

It is a 2020 so I should probably check and see what the date is on the batteries. I have no idea whether they are new or not

At 2020, you are likely needing new batteries.

But like I always recommend -
Take a volt meter - even a $19.95 Walmart or Menards unit will do.
Measure the voltage with the truck off after it's been sitting a couple hours or so (to take off any surface charge, etc.)
Measure it with the volt meter with the truck running.
What you get will tell a whole lot.
I'd bet your voltage with truck off, sitting, is under 12.4 volts.

You'd be surprised at the voltage and time it takes to get a battery charged, even float voltage is higher than you might think.

At 12.4 volts you are only about 50% charged with some batteries (varies with the battery make)

 

[Max-t]

35 years? Ish… but mostly real life stuff… I’m not trained beyond ohms law.


Ok… well 100% functional. You jump a lot of batteries or just charge them on a machine.
go kill a known good battery. Jump it. Drive 5 minutes. Shut it off and see if it’ll start. Every time that hasn’t worked for me, it’s been a bad battery, not a dead one.
When was the last time you had a battery lose charge because “you’re not driving far enough. It’s not a thing.
In fact, the Ess gets used every like 100 yards around here and never discharges, so
Have to laugh

so, the guy brings his car to the dealer, they put a charger on it for 10 hours? And a bad battery took a charge?

 

[Chunky White]

At 2020, you are likely needing new batteries.

But like I always recommend -
Take a volt meter - even a $19.95 Walmart or Menards unit will do.
Measure the voltage with the truck off after it's been sitting a couple hours or so (to take off any surface charge, etc.)
Measure it with the volt meter with the truck running.
What you get will tell a whole lot.
I'd bet your voltage with truck off, sitting, is under 12.4 volts.

You'd be surprised at the voltage and time it takes to get a battery charged, even float voltage is higher than you might think.

Yeah I had a 2020 Grand Cherokee that was bought new that start stop only worked part of the time because I sit in the vehicle for so long 5-6 days per week with the ignition in ACC with the radio on during lunch and before I start work. I get to work early and eat lunch in the Jeep most days so I can take a versus sit on a job site trailer with the guys I work around

 

[Chunky White]

Thanks for the replies!! I will check the battery dates and voltage when I get a chance and possibly replace them with one or two. I think I will look into just one battery and doing away with auto start stop, ESS or whatever its called

 

[ShadowsPapa]

35 years? Ish… but mostly real life stuff… I’m not trained beyond ohms law.


Ok… well 100% functional. You jump a lot of batteries or just charge them on a machine.
go kill a known good battery. Jump it. Drive 5 minutes. Shut it off and see if it’ll start. Every time that hasn’t worked for me, it’s been a bad battery, not a dead one.
When was the la


st time you had a battery lose charge because “you’re not driving far enough. It’s not a thing.
In fact, the Ess gets used every like 100 yards around here and never discharges, so
Have to laugh

so, the guy brings his car to the dealer, they put a charger on it for 10 hours? And a bad battery took a charge?

Wow, a lot wrong there. So the car started - it would start with a 50% charge.
So you think driving 5 minutes charges a battery??

This final phase from 80% to 100% can take a couple of hours -

I've got 50 years in this, as an automotive electrician (college trained) and daily experience.
If the battery is low enough, it may not start again with a short drive home - only because it takes a while to build enough voltage up. If it's down to say 9 volts it may not crank, but may not be bad, either.
A good charger goes through various phases of charging (especially with AGM) and I've got charts showing the hours it can take to get up to even 75% charge. Sure it will start - but leaving it at that kills the battery life. Leaving these at 12 volts long enough will destroy them and yet it will start.

When was the last time you had a battery lose charge because “you’re not driving far enough. It’s not a thing.

LoL, wow. Yeah, it's a thing. It sure is and personal experience has proven it.

I've got 2 (used to be 4) cars that sit a lot certain times of year. No parasitic draw because they are classics without electronics. Batteries lose a charge just SITTING. You can drive them and get them up enough they'll start again, but enough times of getting them up to only 50% - 70% or so and that battery literally loses capacity - and lifespan.
that's a fact I can show with documentation if you like.
Shadetree explaining batteries to trained tech.
I bet my teachers would enjoy seeing this.

I've got to keep battery tenders on my cars when not driven often or far enough. Otherwise - trouble. But as long as they are kept fully charged, a good float charger, I've had batteries last over 12 years. Let it sit - it's not going to make it through warranty.

I deal with auto electric pretty much daily - designed, bread-boarded a voltage regulator circuit for classic cars (electronic) and more.

 

[Chunky White]

I'm wasting my industrial electrician talents by not being more interested in my vehicles batteries it seems. I usually trade every year or so and never have anything as old as the JTR I have now. I work with some very electrically knowledgeable guy but I am the grunt work kind of guy who doesn't mind it, so I don't do much trouble shooting but can figure stuff out on the fly without much thought. I guess two years as an electrical designer helps but I hated that job

 

[ShadowsPapa]

I'm wasting my industrial electrician talents by not being more interested in my vehicles batteries it seems. I usually trade every year or so and never have anything as old as the JTR I have now. I work with some very electrically knowledgeable guy but I am the grunt work kind of guy who doesn't mind it, so I don't do much trouble shooting but can figure stuff out on the fly without much thought. I guess two years as an electrical designer helps but I hated that job

Besides automotive electric (did my first work at age 14 rewiring a bad wiper motor so I could get my first car through inspection so I could buy it), I was maintenance electrician for one company, and they called me "electrician" when I worked at PFG (Principal Financial Group). I did the 110 and 220 wiring for office moves and such. Industrial - heck no. I know where to draw a line!
Got A's on my college papers in auto electric. That instructor didn't do much with T/F tests, you have to diagram things and explain each step along the way.
I really liked transmission and engine work in the shops I worked in but honestly my real love was electric and my shop shows it. Any chance I got for electric work I was all over it.
My love over the years has been automotive electric from complete re-wires to building custom harnesses to restorations to whatever.
Love it. But didn't really mind rewiring my garage with a new panel so I could install a Level 2 charger for our 4xe. That was a nice change.
But I'm trying to back out of things a bit - for a while I had up to 14 things on the shelves to repair and restore for others. I'm finally down to about 10 but want to reduce it even more.

Industrial - nope, no way. I'll let the real pros do that.
But I guess I've been working with 3 phase power - alternator stators, 3 legs, Wye or Delta wired HAHAHA.

 

[Chunky White]

Besides automotive electric (did my first work at age 14 rewiring a bad wiper motor so I could get my first car through inspection so I could buy it), I was maintenance electrician for one company, and they called me "electrician" when I worked at PFG (Principal Financial Group). I did the 110 and 220 wiring for office moves and such. Industrial - heck no. I know where to draw a line!
Got A's on my college papers in auto electric. That instructor didn't do much with T/F tests, you have to diagram things and explain each step along the way.
I really liked transmission and engine work in the shops I worked in but honestly my real love was electric and my shop shows it. Any chance I got for electric work I was all over it.
My love over the years has been automotive electric from complete re-wires to building custom harnesses to restorations to whatever.
Love it. But didn't really mind rewiring my garage with a new panel so I could install a Level 2 charger for our 4xe. That was a nice change.
But I'm trying to back out of things a bit - for a while I had up to 14 things on the shelves to repair and restore for others. I'm finally down to about 10 but want to reduce it even more.

Industrial - nope, no way. I'll let the real pros do that.
But I guess I've been working with 3 phase power - alternator stators, 3 legs, Wye or Delta wired HAHAHA.

I don't work any 3 phase hot only single phase so it isn't scary too me. We check everything before we work on it and if working something HOT we are fully dressed out. I am stuck in the new construction or rebuild category because thats what I am good at and I get too much work done correctly to move up. I enjoy teaching helpers how to do my job and have helped many become electricians sooner than they should have. I am working for one of my old helpers now but he is really smart and was a easy to train.

I guess the thread got off target but IDC

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