ESS "Not Ready Battery Charging" question.

Jebiruph

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Good to know. You mentioned two times that the 3.6L knows of the ESS batteries status. Do you think that testing prior to an ESS event is a third?

I say this because people report that longer trips, where initially that "Not Ready Battery Charging" message appears and ESS doesn't engage, that the message does go away and ESS does kick in. So I have to presume there are additional checks of the ESS battery, even if not just, or necessarily immediately prior to a possible ESS event.

(I know its not easy Jerry to run a multimeter at a stop light to find out some of these things, as you did a stationary rig for the hack!)

I hear you that this message may not be related to charging, even though coincidence may find the alternator of a cranked rig charging both batteries while coincidentally this message appears--making it "true by "coincidence," if that makes any sense, somewhat similar to the fact that if you turn the wheel too much at a stop light, or put the automatic rig into manual, so too ESS won't engage, and yet the alternator is still charging away.
The battery sensor provides constant information related to the condition of the main battery, so that a determination can be made to enable ESS or not. The "Not Ready Battery Charging" message is based on the battery sensors' constant report of the main battery, so as soon as this condition clears on the main battery, the message should go away.
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WranglerMan

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My JLUS gave the “ Battery charging ESS not ready” message about a year ago and when the dealer checked the battery they found the main failed some type of test so they replaced it and I have not had any issues since, I do see the EVIC display 14.3 when it’s been sitting for several days but after driving it slowly drops to the low 13’s and never displays any error messages.

Once a month I do put my JL on a tender for the day just to bring it back to 100%
 

Rahneld

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The battery sensor provides constant information related to the condition of the main battery, so that a determination can be made to enable ESS or not. The "Not Ready Battery Charging" message is based on the battery sensors' constant report of the main battery, so as soon as this condition clears on the main battery, the message should go away.
Thanks. While this makes perfect sense, I would have thought that similar checks would also, if not primarily would have gone to the ESS battery as well. Maybe they do and you can confirm this....?

Certainly FCA has existing components to effect this main battery check from other members of the fleet that do ESS with one battery, not two like the Wrangler JL. : - )
 

Jebiruph

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Thanks. While this makes perfect sense, I would have thought that similar checks would also, if not primarily would have gone to the ESS battery as well. Maybe they do and you can confirm this....?

Certainly FCA has existing components to effect this main battery check from other members of the fleet that do ESS with one battery, not two like the Wrangler JL. : - )
There isn't a battery sensor on the aux battery, so it's real time condition is unknown. If I'm a JL, here's what I need to know to determine if I should enable ESS. Does the main battery have enough power to crank the starter and can the aux battery power the electronics during an auto stop? That's why the battery relay is blipped during a cold start, it's testing the ability of the aux battery to power the electronics by itself. If it can't power the electronics, the starting process is terminated. Once started, the battery sensor provides real time information on the main battery's ability to crank the starter.
 

Rahneld

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There isn't a battery sensor on the aux battery, so it's real time condition is unknown. If I'm a JL, here's what I need to know to determine if I should enable ESS. Does the main battery have enough power to crank the starter and can the aux battery power the electronics during an auto stop? That's why the battery relay is blipped during a cold start, it's testing the ability of the aux battery to power the electronics by itself. If it can't power the electronics, the starting process is terminated. Once started, the battery sensor provides real time information on the main battery's ability to crank the starter.
Thanks Jerry. But if you wouldn't mind answering this for me as it regards the 3.6L that would be great:

As some members have reported, ESS may not be available upon cold crank--aside from all the basic reasons like engine cold, wheel turned, automatic in manual mode, etc.

Over time, as the engine warms up ESS continues to remain out of commission, sometimes requiring a long trip to engage, I thought the reason was the time was given to the alternator to charge the ESS battery (actually both batteries given that they're in parallel when the rig's cranked but not in ESS mode)...and yet there's no way of testing the ESS battery mid trip?

Perhaps the test of the main battery you speak of is sufficient as given its ample charge and connection to the ESS battery in parallel in these situations, that would imply the ESS battery would also be well charged.

What I'm trying to say is that I'm working on the theory that either battery lacking power drains from the stronger one given the parallel connection and that by corollary, if either battery is fully charged, the other must be.

Is that why testing of the main battery only needs to be effected while the rig's traveling?

Thanks.
 

Jebiruph

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Thanks Jerry. But if you wouldn't mind answering this for me as it regards the 3.6L that would be great:

As some members have reported, ESS may not be available upon cold crank--aside from all the basic reasons like engine cold, wheel turned, automatic in manual mode, etc.

Over time, as the engine warms up ESS continues to remain out of commission, sometimes requiring a long trip to engage, I thought the reason was the time was given to the alternator to charge the ESS battery (actually both batteries given that they're in parallel when the rig's cranked but not in ESS mode)...and yet there's no way of testing the ESS battery mid trip?

Perhaps the test of the main battery you speak of is sufficient as given its ample charge and connection to the ESS battery in parallel in these situations, that would imply the ESS battery would also be well charged.

What I'm trying to say is that I'm working on the theory that either battery lacking power drains from the stronger one given the parallel connection and that by corollary, if either battery is fully charged, the other must be.

Is that why testing of the main battery only needs to be effected while the rig's traveling?

Thanks.
I haven't crafted explanations for everything yet, but it seems like the whole system is very conservative and really wants to make sure everything is ready before enabling ESS.

When the engine is running, a weak battery will not affect a strong battery because they are both over powered by the alternator.

It's not so much that the main battery is only tested when the engine is running, the battery sensor is constantly measuring power into and out of the battery and that information is part of the calculation of the state of the battery. The engineers that designed the system could be extrapolating the condition of the aux battery from other information, but as of now I doubt it.

If you haven't read the relevant threads from the master thread (https://www.jlwranglerforums.com/forum/threads/3-6l-ess-dual-battery-consolidated-information.25377/) lately, try rereading them. Some of it may make more sense now.
 

FlatSixShooter

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Thanks Jerry. But if you wouldn't mind answering this for me as it regards the 3.6L that would be great:

As some members have reported, ESS may not be available upon cold crank--aside from all the basic reasons like engine cold, wheel turned, automatic in manual mode, etc.

Over time, as the engine warms up ESS continues to remain out of commission, sometimes requiring a long trip to engage, I thought the reason was the time was given to the alternator to charge the ESS battery (actually both batteries given that they're in parallel when the rig's cranked but not in ESS mode)...and yet there's no way of testing the ESS battery mid trip?

Perhaps the test of the main battery you speak of is sufficient as given its ample charge and connection to the ESS battery in parallel in these situations, that would imply the ESS battery would also be well charged.

What I'm trying to say is that I'm working on the theory that either battery lacking power drains from the stronger one given the parallel connection and that by corollary, if either battery is fully charged, the other must be.

Is that why testing of the main battery only needs to be effected while the rig's traveling?

Thanks.

If both batteries are “fully charged”, but (Due to deterioration) one will only charge to, say 85% of its original cca capacity while the other recharges to 100% of original capacity, then as the charging input is switched off, the combined batteries will eventually settle somewhere in between. In my experience, it’s also possible, for any monitored charging system, to likely continue to try to charge a partially deteriorated battery much longer than one that recovers fully and quickly. Does that make sense ?
 

Rahneld

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If both batteries are “fully charged”, but (Due to deterioration) one will only charge to, say 85% of its original cca capacity while the other recharges to 100% of original capacity, then as the charging input is switched off, the combined batteries will eventually settle somewhere in between. In my experience, it’s also possible, for any monitored charging system, to likely continue to try to charge a partially deteriorated battery much longer than one that recovers fully and quickly. Does that make sense ?
Freakin' yes. It's the premise for my concern over the design of the 3.6L's electric power plant and perhaps why this rig only needs to test the main battery for overall rig battery power across both batteries as Jerry sort of described above.

Need I tell you, like two separated columns of water of different heights, hooking these two columns together is analogous to connecting the batteries in parallel, as they are 99% of the time (positive to positive, negative to negative.)

As in the water example, where the adage "water seeks its own level" applies, in short order both water columns will achieve the same height was connected. Strong evidence exists that even the Egyptians knew this when building the pyramids.

And in analogy, the battery with the greater amount of current will charge the one with less when connected together in parallel. : - )
 
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BrntWS6

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Decided to schedule an appointment with my dealer to test everything. Trickle charged the batteries and the Jeep sat for 1 day. Took it for an hour drive today and it showed "charging" the entire time.
 

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Decided to schedule an appointment with my dealer to test everything. Trickle charged the batteries and the Jeep sat for 1 day. Took it for an hour drive today and it showed "charging" the entire time.
good move, I had my battery's replaced after 14 months, It always showed ESS charging.
 
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BrntWS6

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Well, my dealer did a 3hr battery test and everything checked out okay. This system is just not that efficient at charging the 2 batteries. But i am glad that nothing was wrong. They did give me a software update and V41 damper so not a total waste.
 

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Well, my dealer did a 3hr battery test and everything checked out okay. This system is just not that efficient at charging the 2 batteries. But i am glad that nothing was wrong. They did give me a software update and V41 damper so not a total waste.
That sounds very suspicious to me. Mine sat on the lot for maybe 8 months before I bought it. It’s my weekend driver and sits often for a few weeks between drives. In almost 8 months I have maybe 4,200 miles on it and I never get that ESS charging error.

I would think that you have if not a problem with one or both batteries then you have a charging system problem. I don’t think the system is bad at charging the batteries if it’s working properly.

User @Jebiruph is the resident expert here on the ESS system it seems, maybe solicit his opinion.
 
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