Dual Battery Questions

[allieboy]

Thank you. That's good advice..I'll do it your way. : - )

Great info! Thank you both!

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[allieboy]

@Rahneld

In regard to adding a switch to the jumper. Why would you do this. Not necessary and just opens you up to other issues. Forget the switch, idea.. IF you must, just install the jumper and leave the fuse out. Takes a second to insert the fuse when you want to bring the jumper into play.

Reality is ..... I would not even leave the jumper attached all the time. You will truly regret this if you have an issue or not and the dealership service department sees the jumper.

With that said, you better sure as heck, remove the jumper if you have an FCA provided flat tow truck transport your JL to the dealer. You better not have it installed when you go to the dealer for oil changes, etc..

Smart move on your part would be just to keep the jumper, the fuse and the necessary M6-1.0, nuts for NB1 and N2 in the JL.

Having a wing nut on the ESS neutral would be no big deal... if dealer asks about the wing nut .....say "that is all I had that fit and I lost the stock nut.

Dealership will cry foul if they see a jumper attached. You just are asking for trouble telling them about it or letting them see it installed.

Hopefully, a rare day in hell when you will actually need/use the jumper so why, why leave it attached there? Not me...

Yes, you are prudent having such a jumper and the knowledge on how to bring it into play.

.

Out of curiosity...what guage wire on yours?

 

[Rahneld]

Why do people make this such voodoo. Auxiliary batteries and start stop systems have been around for a decade. All the Aux does is keep constant power to sensing electronics and such.

Mr @Hgrace...hi..

The reason why this is of concern to me--much that you are correct that stop start systems are common and mature technologies--is that...

as I understand it--I could be wrong, others please correct me if I am, FCA designed the JL's start stop (ESS) system on the 3.6L such that the ESS battery, which to my mind operates a non-essential function on the vehicle (i.e. stop/start) is additionally, solely responsible** for energizing the starter relay when the vehicle operator attempts a cold crank.

This means that if the ESS battery lacks enough power, the starter relay can't communicate with the starter and the vehicle will not crank.

What little I learned from subject matter specialists @Rhinebeck01 and @Jebiruph on this here leave me--perhaps out of ignorance, wondering why FCA designed things this way. Why would you make a little battery devoted to a non-mission critical system (start/stop) mission (cranking) critical?

** I want to clarify something I said. It is my understanding that only upon a crank event are the batteries isolated. At rest or at successful crank I understand the batteries to be connected in parallel. So, yes, the main battery essentially (along with the alternator with the vehicle is successfully cranked) charge the ESS battery to energize the starter relay, but at cold crank, even if for a brief instant, the ESS battery is all alone to initiate the crank sequence and is the weak link in this chain IMHO. If it won't take charge, barring Mr. @Jebiruph's N1<->N2 workaround, I think we'll be stuck.

At least if the ESS battery dies post successful crank during vehicle operation, in theory, ESS won't be engaged, the system first sensing a problem with the ESS battery and not engaging the ESS system.


~~~~

 

[allieboy]

Mr @Hgrace...hi..

The reason why this is of concern to me--much that you are correct that stop start systems are common and mature technologies--is that...

as I understand it--I could be wrong, others please correct me if I am, FCA designed the JL's start stop (ESS) system on the 3.6L such that the ESS battery, which to my mind operates a non-essential function on the vehicle (i.e. stop/start) is additionally, solely responsible** for energizing the starter relay when the vehicle operator attempts a cold crank.

This means that if the ESS battery lacks enough power, the starter relay can't communicate with the starter and the vehicle will not crank.

What little I learned from subject matter specialists @Rhinebeck01 and @Jebiruph on this here leave me--perhaps out of ignorance, wondering why FCA designed things this way. Why would you make a little battery devoted to a non-mission critical system (start/stop) mission (cranking) critical?

** I want to clarify something I said. It is my understanding that only upon a crank event are the batteries isolated. At rest or at successful crank I understand the batteries to be connected in parallel. So, yes, the main battery essentially (along with the alternator with the vehicle is successfully cranked) charge the ESS battery to energize the starter relay, but at cold crank, even if for a brief instant, the ESS battery is all alone to initiate the crank sequence and is the weak link in this chain IMHO. If it won't take charge, barring Mr. @Jebiruph's N1<->N2 workaround, I think we'll be stuck.

At least if the ESS battery dies post successful crank during vehicle operation, in theory, ESS won't be engaged, the system first sensing a problem with the ESS battery and not engaging the ESS system.


~~~~

great post!

 

[Rhinebeck01]

Out of curiosity...what guage wire on yours?

@allie

14 gauge

But I myself am clueless as to what gauge is the best to use.

 

[allieboy]

@allie

14 gauge

But I myself am clueless as to what gauge is the best to use.

Thanks!

 

[Jebiruph]

@allie

14 gauge

But I myself am clueless as to what gauge is the best to use.

I ran my 14 gauge jumper with a 30 amp fuse for a month with no problems. I used 14 gauge because it was conveniently available.

 

[Rahneld]

I ran my 14 gauge jumper with a 30 amp fuse for a month with no problems. I used 14 gauge because it was conveniently available.

Mr @Jebiruph - this is a semi-permanent install for you and not just one you've chosen to hook up only if the ESS battery fails---Mr @Rhinebeck01's well made points about not presenting it that way to the dealer notwithstanding?

 

[Hgrace]

Just curious, what's the compression ratio of your V8's and V10. It's 11.3:1 in the Wrangler 3.6. I suspect compression ratio has more impact on starting than rotating mass. It would be interesting to know how much energy is needed to start different engines.

What model is your Schumacher? I need to get something, may as well get something good.

It's a 1200. My JL hasn't gone dead and I'm not too concerned. My V10 has 9.2: 1 compression and 4 more cylinders and nearly twice the displacement and my 2006 Charger is 10.1:1 and both spun up no problem.

 

[Hgrace]

Mr @Hgrace...hi..

The reason why this is of concern to me--much that you are correct that stop start systems are common and mature technologies--is that...

as I understand it--I could be wrong, others please correct me if I am, FCA designed the JL's start stop (ESS) system on the 3.6L such that the ESS battery, which to my mind operates a non-essential function on the vehicle (i.e. stop/start) is additionally, solely responsible** for energizing the starter relay when the vehicle operator attempts a cold crank.

This means that if the ESS battery lacks enough power, the starter relay can't communicate with the starter and the vehicle will not crank.

What little I learned from subject matter specialists @Rhinebeck01 and @Jebiruph on this here leave me--perhaps out of ignorance, wondering why FCA designed things this way. Why would you make a little battery devoted to a non-mission critical system (start/stop) mission (cranking) critical?

** I want to clarify something I said. It is my understanding that only upon a crank event are the batteries isolated. At rest or at successful crank I understand the batteries to be connected in parallel. So, yes, the main battery essentially (along with the alternator with the vehicle is successfully cranked) charge the ESS battery to energize the starter relay, but at cold crank, even if for a brief instant, the ESS battery is all alone to initiate the crank sequence and is the weak link in this chain IMHO. If it won't take charge, barring Mr. @Jebiruph's N1<->N2 workaround, I think we'll be stuck.

At least if the ESS battery dies post successful crank during vehicle operation, in theory, ESS won't be engaged, the system first sensing a problem with the ESS battery and not engaging the ESS system.


~~~~

The ESS battery DOES NOT START THE VEHICLE.

 

[Rahneld]

The ESS battery DOES NOT START THE VEHICLE.

I respect this Mr @Hgrace. In fact I agree. The starter, which starts the vehicle, is connected--or so I understand--either to the main or ESS batteries--no argument there. This is why you can start the 3.6 with only the ESS battery connected.

Where I have concern though is with the idea--maybe I am wrong--that your point is (I don't mean to sound hurtful)...irrelevant.

Here's my point and why I think this way. I could be wrong. Please correct me if I am.

If the starter relay, which triggers that starter to work, relies solely on the ESS battery, either at cold crank or ESS startup, even if only for a moment in time, then effectively, if not technically, the ESS battery does in effect , essentially start the vehicle because without it energized, the starter relay won't tell the starter to crank the engine, even if the latter has all the power in the world to do so and is just waiting for the go ahead from the dead starter relay to do so.

Please let me know if that logic is flawed.

You're right, and yet, I wonder if also on point.

Peace to you.

: - )

 

[allieboy]

I respect this Mr @Hgrace. In fact I agree. The starter, which starts the vehicle, is connected--or so I understand--either to the main or ESS batteries--no argument there. This is why you can start the 3.6 with only the ESS battery connected.

Where I have concern though is with the idea--maybe I am wrong--that your point is (I don't mean to sound hurtful)...irrelevant.

Here's my point and why I think this way. I could be wrong. Please correct me if I am.

If the starter relay, which triggers that starter to work, relies solely on the ESS battery, either at cold crank or ESS startup, even if only for a moment in time, then effectively, if not technically, the ESS battery does in effect , essentially start the vehicle because without it energized, the starter relay won't tell the starter to crank the engine, even if the latter has all the power in the world to do so and is just waiting for the go ahead from the dead starter relay to do so.

Please let me know if that logic is flawed.

You're right, and yet, I wonder if also on point.

Peace to you.

: - )

No need to tiptoe. You have great knowledge and along with @Jebiruph have helped me tremendously! I'm using the bumper for emergency use. Some will, some won't, so what, NEXT! Thanks again for your help.

 

[Jebiruph]

I respect this Mr @Hgrace. In fact I agree. The starter, which starts the vehicle, is connected--or so I understand--either to the main or ESS batteries--no argument there. This is why you can start the 3.6 with only the ESS battery connected.

Where I have concern though is with the idea--maybe I am wrong--that your point is (I don't mean to sound hurtful)...irrelevant.

Here's my point and why I think this way. I could be wrong. Please correct me if I am.

If the starter relay, which triggers that starter to work, relies solely on the ESS battery, either at cold crank or ESS startup, even if only for a moment in time, then effectively, if not technically, the ESS battery does in effect , essentially start the vehicle because without it energized, the starter relay won't tell the starter to crank the engine, even if the latter has all the power in the world to do so and is just waiting for the go ahead from the dead starter relay to do so.

Please let me know if that logic is flawed.

You're right, and yet, I wonder if also on point.

Peace to you.

: - )

The way I read the factory schematic, the starter solenoid relay is powered by the ESS battery and switches power from the Mian battery to the starter solenoid, so both batteries are used.

 

[Rahneld]

The way I read the factory schematic, the starter solenoid relay is powered by the ESS battery and switches power from the Mian battery to the starter solenoid, so both batteries are used.

Thank you. I take this to mean that only the ESS battery energizes the relay to the starter, then a connection between the 2 batteries in parallel is effected, and then the starter begins to do its work, drawing its power from essentially either/both batteries.

It is the word both above Mr @Hgrace that leads me to believe that rather that the ESS battery doesn't start the vehicle, that it can, or effectively assist in doing so because it is connected in parallel to the main battery just prior to the starter cranking the engine.

(I just want to get it right...nothing else.) : - )

 

[Jebiruph]

The way I read the factory schematic, the starter solenoid relay is powered by the ESS battery and switches power from the Mian battery to the starter solenoid, so both batteries are used.

@Rahneld, this only applies during an ESS event when the batteries are separated, all other times both batteries power everything. You'll have to find some way to prove an initial cold start is an ESS event.

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