ESS Dual Battery Management

[Yellow Cake Kid]

SOH

Sponsored

 

[Jebiruph]

SOH

Disagree

 

[Yellow Cake Kid]

ok

 

[WranglerMan]

@JeepScares i just caught this in your post:

When the batteries are disconnected from the parallel array it would seem that the IBS should be connected to the battery that is being charged otherwise the charging system can not provide an optimized charging cycle.

Placing the IBS on the disconnected secondary battery while charging only the primary battery introduces some possibilities that warrant further consideration. My first thought is that the Body Control Module will be instructing the alternator, via the field control and current regulation, to charge the battery in accordance with a strategy befitting the state of the battery that is disconnected, while the battery that is actually connected is being charged with no regard for the state of the art of Intelligent Battery Charging.

That seems like something worth pondering.

On the Genesis system the batteries are connected as one thru the smart isolator 99.99% of the time, the only time they are separated is if the main crank battery falls below 12.7 +/-.1 so in all honestly having the IBS connected to either would be fine as when they are connected it’s a equalized charge so both batteries are the same voltage +/-.1

Here are a weeks worth of voltage readings taken directly off the batteries, the first 6 readings are very close and the solenoid was closed indicated by the low resistance reading and the day #7 reading the resistance was high across the solenoid indicating it’s open and the voltages were different, the isolator by design in normally open until voltage is applied and this is dictated by whether the main crank battery is above 13.2 and when it sees that voltage above that number for several minutes it closes and connects the two so the IBS sees the combined equalized voltage and charges accordingly, the only time the IBS would be isolated from being read to adjust charging the main crank battery is during the first few minutes of running.

Day #1 = 12.8/12.7

Day #2 = 12.8/12.8

Day #3 =12.7/12.7

Day #4 = 12.6/12.6

Day #5 =12.6/12.7

Day #6 = 12.6/12.7 (0.7 isolator closed low resistance)

Day #7 = 12.59/12.64 (150-200 isolator open high resistance)

 

[Yellow Cake Kid]

...having the IBS connected to either would be fine as when they are connected it’s a equalized charge...

I agree that when the batteries are connected the IBS placement is not substantially different than that of the OEM system.

Thank you for explaining and for providing the additional information.

 

[Yellow Cake Kid]

I have been trying to conceptualize how measurements made at the shunt resistor are affected by the second battery.

In the image shown here I have made an assumption that the shunt resistor is wired as such, mainly because this layout conforms to a premise that the current flow may only measure actions of the primary battery.

The other option, where the batteries' negative terminals may be connected before the shunt would be easier to conceptualize, but the scenario shown seems to present an interesting puzzle, and from outward appearance it seems as if the IBS is laid out as shown here.

The part that puzzles me, is considering how the voltage interaction between the two batteries might influence the pertinence of measurements made at the shunt resistor. When a load is placed on the primary battery, the secondary battery will react, and I am wondering how this applies to the readings being made.

 

[Gee-pah]

Hi @Jebiruph Jerry:

Your ingenious designs seem to lead me full circle back to something you and I have discussed on the forum in the past about jump starting on solely the ESS/Aux battery, in the 3.6L JL[U], but that you raised issue with, as it regards the dangers of placing the positive lead of a battery charger/jumper cables anyplace but on the positive terminal of the main battery, consistent with the warnings in model year 2019 and beyond owner's manuals.

Lets assume the 3.6L JL[U] owner is stranded with two dead batteries in the middle of nowhere, a power pack not unlike the Noco you show pictured, and an implementation of your design, as discussed below where a second "Master Power Cut-off Switch" has been added on the positive side between the two batteries.

Yes--properly implementing your design could prevent the above paragraph's scenario where the batteries both go dead. I will certainly give you that.

But the scenario is not unlikely in the sense that the normal configuration from the factory is for the two batteries, as you know, to be connected in parallel while the vehicle is parked. And given this, any appliance drawing current, connected to either battery, will essentially grab it from both batteries.

I'm not saying the above is advised out in the middle of some overland adventure, say, running camping gear, but let's assume for argument sake it happens.

As your picture below shows, you've simply connected a wire from N1 (i.e. the positive ESS/Aux battery) to the positive post of the main battery--which is the same as jumpering N1 and N2. Your charger is connected on the negative side to only the ESS/Aux battery as you demonstrate solely ESS/Aux battery charging.

Given the ESS/Aux battery is smaller, given that if adequately charged it is capable of cranking the rig (in fact must be adequately charged in the un-flashed 2018 for the vehicle to crank, baring tricking the vehicle with say a 1 battery setup, as doable with your design) I am curious to your thoughts (revisited again) on (in this order) 1) affecting that which your picture above shows, 2) breaking the positive side connection between the batteries, 3) reconnecting the grounds, (where the charge in the ESS/Aux battery can not discharge into the dead main battery because of the disconnection of the two batteries now at the positive side) and attempting a crank of the rig.

Once successfully cranked, reconnecting the positive side between the two batteries can occur so that the alternator can get in the business of charging both batteries.

In model years 2019 and beyond (which can cold crank on either battery,) the alternative, charging just the main battery, or charging both batteries, it would seem, is apt to tax a power pack's cranking power in the discharge it faces first, placing necessary charge in either or both batteries. If would seem that what I propose offers the fastest and greatest chance of success at cranking the vehicle, as your power pack or less equipped ones may lack the "horsepower" to effect your basic jump start from another cranked vehicle as shown in the owner's manual.

I'm curious to your thoughts on my scenario.

Thank you for your time and consideration.

And I fully appreciate that one reply of yours might be, 'my designs can prevent you from discharging the ESS/Aux battery in the first place as you describe.'

 

[Jebiruph]

Hi @Jebiruph Jerry:

Your ingenious designs seem to lead me full circle back to something you and I have discussed on the forum in the past about jump starting on solely the ESS/Aux battery, in the 3.6L JL[U], but that you raised issue with, as it regards the dangers of placing the positive lead of a battery charger/jumper cables anyplace but on the positive terminal of the main battery, consistent with the warnings in model year 2019 and beyond owner's manuals.

Lets assume the 3.6L JL[U] owner is stranded with two dead batteries in the middle of nowhere, a power pack not unlike the Noco you show pictured, and an implementation of your design, as discussed below where a second "Master Power Cut-off Switch" has been added on the positive side between the two batteries.

Yes--properly implementing your design could prevent the above paragraph's scenario where the batteries both go dead. I will certainly give you that.

But the scenario is not unlikely in the sense that the normal configuration from the factory is for the two batteries, as you know, to be connected in parallel while the vehicle is parked. And given this, any appliance drawing current, connected to either battery, will essentially grab it from both batteries.

I'm not saying the above is advised out in the middle of some overland adventure, say, running camping gear, but let's assume for argument sake it happens.

As your picture below shows, you've simply connected a wire from N1 (i.e. the positive ESS/Aux battery) to the positive post of the main battery--which is the same as jumpering N1 and N2. Your charger is connected on the negative side to only the ESS/Aux battery as you demonstrate solely ESS/Aux battery charging.

Given the ESS/Aux battery is smaller, given that if adequately charged it is capable of cranking the rig (in fact must be adequately charged in the un-flashed 2018 for the vehicle to crank, baring tricking the vehicle with say a 1 battery setup, as doable with your design) I am curious to your thoughts (revisited again) on (in this order) 1) affecting that which your picture above shows, 2) breaking the positive side connection between the batteries, 3) reconnecting the grounds, (where the charge in the ESS/Aux battery can not discharge into the dead main battery because of the disconnection of the two batteries now at the positive side) and attempting a crank of the rig.

Once successfully cranked, reconnecting the positive side between the two batteries can occur so that the alternator can get in the business of charging both batteries.

In model years 2019 and beyond (which can cold crank on either battery,) the alternative, charging just the main battery, or charging both batteries, it would seem, is apt to tax a power pack's cranking power in the discharge it faces first, placing necessary charge in either or both batteries. If would seem that what I propose offers the fastest and greatest chance of success at cranking the vehicle, as your power pack or less equipped ones may lack the "horsepower" to effect your basic jump start from another cranked vehicle as shown in the owner's manual.

I'm curious to your thoughts on my scenario.

Thank you for your time and consideration.

And I fully appreciate that one reply of yours might be, 'my designs can prevent you from discharging the ESS/Aux battery in the first place as you describe.'

For your first point, I wasn't thinking when I moved the charger's positive cable to the N1 side of the jumper, it should have stayed on the positive battery terminal. I have a new set of pictures to show that. And that is a medium sized Noco charger and not a battery pack.

I think the issue with jumpstarting with the positive cable attached N1, that provoked the owner's manual warning of death, was the potential of exceeding the current rating of the aux battery and associated cables with the jumpstarting current.

But if you left the jumpstarting positive cable connected to the main battery's positive terminal (that is connected directly to the starter), disconnect the ground cable from the main battery leaving the aux battery ground connected and connect the jumpstarting negative to that disconnected cable, you would be jumpstarting with the main battery disconnected and not sending starting current through the aux battery and it's cables.

It's similar to what this new system does, but it's using a charged aux battery instead of jumpstarting.

 

[Jebiruph]

I have been trying to conceptualize how measurements made at the shunt resistor are affected by the second battery.

In the image shown here I have made an assumption that the shunt resistor is wired as such, mainly because this layout conforms to a premise that the current flow may only measure actions of the primary battery.

The other option, where the batteries' negative terminals may be connected before the shunt would be easier to conceptualize, but the scenario shown seems to present an interesting puzzle, and from outward appearance it seems as if the IBS is laid out as shown here.

The part that puzzles me, is considering how the voltage interaction between the two batteries might influence the pertinence of measurements made at the shunt resistor. When a load is placed on the primary battery, the secondary battery will react, and I am wondering how this applies to the readings being made.

Here's how I understand the system works. The IBS shunt resistor is used to measure the current into and out of the battery. At some point, the IBS learns the battery and at any point of time knows how much charge is in the battery. Overtime as the battery deteriorates (builds internal resistance) the IBS will detect that for a given state of charge and a given voltage, there is less charging current going into the battery, indicating a change in the health of the battery. I don't think anything outside of the battery (except the voltage of the system) impacts the IBS calculations.

 

[Gee-pah]

For your first point, I wasn't thinking when I moved the charger's positive cable to the N1 side of the jumper, it should have stayed on the positive battery terminal. I have a new set of pictures to show that. And that is a medium sized Noco charger and not a battery pack.

I think the issue with jumpstarting with the positive cable attached N1, that provoked the owner's manual warning of death, was the potential of exceeding the current rating of the aux battery and associated cables with the jumpstarting current.

But if you left the jumpstarting positive cable connected to the main battery's positive terminal (that is connected directly to the starter), disconnect the ground cable from the main battery leaving the aux battery ground connected and connect the jumpstarting negative to that disconnected cable, you would be jumpstarting with the main battery disconnected and not sending starting current through the aux battery and it's cables.

It's similar to what this new system does, but it's using a charged aux battery instead of jumpstarting.

I believe I follow what you are saying, which is that the NOCO charges neither battery in what you describe to me immediately above, just connects to the starter, and a ground that solely leads to the vehicle's body ground because that ground has first been detached from the main battery's negative terminal. Ok.

But this is all predicated Jerry, if I follow you, on the ESS/Aux battery having charge, as if it doesn't, neither will an un-flashed 2018 3.6L JL[U] crank, nor (I think) will a model year 2019 or later 3.6L JL[U] be able to resort to its logic of switching over to the main battery (dead or fully charged) when the ESS/Aux battery lacks adequate charge, because the main battery's ground has been temporarily removed in your described immediately above scenario, and that main battery temporarily sits independent of everything, with no complete circuit on it.

So..in the desire to not risk overloading a dead ESS/Aux battery in my scenario (either from a Noco or crank donor vehcile) where that little battery along with the main battery is dead, it sounds like there are two acceptable courses of action Put the NOCO on the main battery's terminals as per the owner's manual, with all cables on all batteries, and

1) If running a flashed 2018 3.6L JL[U] or a model year 2019 or later 3.6L JL[U], which can start with either battery, bypass the Aux battery by opening your "Master Power Cut-off Switch," --as that's better than attaching the Noco to both batteries because it drains the Noco less, or

2) Or if running a un-flashed 2018 where the ESS/Aux battery must have current, or if you think #1 above ill advised, have your "Master Power Cut-off Switch," closed, and bypass jumper installed or not, (as when the 3.6L is parked, both batteries are in parallel anyway so it doesn't much matter if your jumper is installed) and in time, as per the manual, attempt a crank with both batteries having just gotten juice from the Noco.

Do you dislike #1?

(I really wish I could put the Noco's negative side on all the main battery's negative cables, temporarily detached from the main battery, with your bypass jumper in place and your "Master Power Cut-off Switch," if installed, in the closed position, and give the ESS/Aux battery some juice, and attempt a crank. It sounds like this approach concerns you though in the possibility of overloading the ESS/Aux battery.)


Thank you.

 

[Jebiruph]

I believe I follow what you are saying, which is that the NOCO charges neither battery in what you describe to me immediately above, just connects to the starter, and a ground that solely leads to the vehicle's body ground because that ground has first been detached from the main battery's negative terminal. Ok.

But this is all predicated Jerry, if I follow you, on the ESS/Aux battery having charge, as if it doesn't, neither will an un-flashed 2018 3.6L JL[U] crank, nor (I think) will a model year 2019 or later 3.6L JL[U] be able to resort to its logic of switching over to the main battery (dead or fully charged) when the ESS/Aux battery lacks adequate charge, because the main battery's ground has been temporarily removed in your described immediately above scenario, and that main battery temporarily sits independent of everything, with no complete circuit on it.

So..in the desire to not risk overloading a dead ESS/Aux battery in my scenario (either from a Noco or crank donor vehcile) where that little battery along with the main battery is dead, it sounds like there are two acceptable courses of action Put the NOCO on the main battery's terminals as per the owner's manual, with all cables on all batteries, and

1) If running a flashed 2018 3.6L JL[U] or a model year 2019 or later 3.6L JL[U], which can start with either battery, bypass the Aux battery by opening your "Master Power Cut-off Switch," --as that's better than attaching the Noco to both batteries because it drains the Noco less, or

2) Or if running a un-flashed 2018 where the ESS/Aux battery must have current, or if you think #1 above ill advised, have your "Master Power Cut-off Switch," closed, and bypass jumper installed or not, (as when the 3.6L is parked, both batteries are in parallel anyway so it doesn't much matter if your jumper is installed) and in time, as per the manual, attempt a crank with both batteries having just gotten juice from the Noco.

Do you dislike #1?

(I really wish I could put the Noco's negative side on all the main battery's negative cables, temporarily detached from the main battery, with your bypass jumper in place and your "Master Power Cut-off Switch," if installed, in the closed position, and give the ESS/Aux battery some juice, and attempt a crank. It sounds like this approach concerns you though in the possibility of overloading the ESS/Aux battery.)


Thank you.

In what I described, the aux would be getting charged during the jumpstart. My answer was based on the picture that show the bypass jumper installed. Without the jumper, an unflashed 2018 wouldn't start.

There isn't any battery switching logic, any attached battery will participate in providing cranking power to the starter.

As to your theories, I mostly think simpler is better. If some one think's they have a better way to jumpstart, go for it, but my advice is just connect to the main battery terminal like any other vehicle and as described in the owners manual.

You should acquire some old batteries and test your theories.

 

[Rubicon_LA]

I just had a scenario on my 2018 JLUR when both batteries died. With a jumper connection between N1 and N2 and disconnected negative terminal of AUX battery I was able to jumpstart the vehicle connecting the NOCO charger to both main battery terminals.

 

[Jebiruph]

I just had a scenario on my 2018 JLUR when both batteries died. With a jumper connection between N1 and N2 and disconnected negative terminal of AUX battery I was able to jumpstart the vehicle connecting the NOCO charger to both main battery terminals.

As much as the different jumpstart techniques get talked about, this is the first time I've seen a post from someone actually doing it this way. Which model NOCO did you use?

 

[Rubicon_LA]

NOCO Boost Plus GB40 1000 Amp

 

[Gee-pah]

I just had a scenario on my 2018 JLUR when both batteries died. With a jumper connection between N1 and N2 and disconnected negative terminal of AUX battery I was able to jumpstart the vehicle connecting the NOCO charger to both main battery terminals.

Hi @Rubicon_LA:

Just as a sanity check for me, did you

• put the "disconnected negative terminal of [the] AUX battery" back on the main battery's negative post after this main battery charge, but before the crank, or
• has your 2018 3.6L JLUR been flashed to permit it to crank with either battery--or
• is it not a 3.6L engine?

I ask this because I believe that a 2018 JLUR 3.6L vehicle will require the ESS/Aux battery to have power before a crank is attempted unless

• 1) the aforementioned flash has been effected on your 2018 3.6L, and/or
• 2) you have hard wired a parallel connection between the 2 batteries 100% of the time, so a test of one battery is a test of the other, given
• 3) not only your N1<->N2 jumper, but presumably, your reconnection of the ESS/Aux battery's ground to the main battery's negative post prior to the cold crank, so the vehicle's pre-crank test of the ESS/Aux battery is really a composite voltage test of both batteries, vis a vis this hard wiring parallel connection you speak of.

I am very glad to hear of a power pack that has shown itself capable enough to get an entirely 3.6L [???] JL going, perhaps because of or facilitated by use of one of Jerry's @Jebiruph proposed configurations.
Thank you for sharing.

Sponsored