3.6L ESS Aux Battery Bypass

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Jebiruph

Jebiruph

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I’m wondering/hoping that the ESS hood switch deactivation will allow a maximum lifespan for this aux battery. Also if this battery does fail will you still be able to start and drive the Jeep?
As long as the factory connections are intact, the Aux battery will be providing power and getting charged the same as the Main battery because the batteries are connected together, except when auto stopped. So with ESS disabled, there is till wear on the Aux battery.



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As long as the factory connections are intact, the Aux battery will be providing power and getting charged the same as the Main battery because the batteries are connected together, except when auto stopped. So with ESS disabled, there is till wear on the Aux battery.
With your setup this essentially is disconnecting the aux battery completely.
 

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No messages or problems indicated, just don't think it should be 14.7v all the time. The constant 14.7v is as is from the factory, no changes to the electrical system.
When watching my voltage using the Jeep instrument panel, my voltage stays at 14.7-14.8. I haven’t ever seen it go below that. And that’s with the Tazer married and connected for live functions. When I removed it I didn’t see any difference in the voltage. Does that mean I actually have a problem?
 
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When watching my voltage using the Jeep instrument panel, my voltage stays at 14.7-14.8. I haven’t ever seen it go below that. And that’s with the Tazer married and connected for live functions. When I removed it I didn’t see any difference in the voltage. Does that mean I actually have a problem?
I believe my system constantly reading 14.7 volts is not operating as designed. The constant high voltage itself is not a problem as varying the voltage is done for economy and battery health, so marginal benefit. My biggest concern was a possible failing Aux battery, but I bypassed it and nothing changed. I'm not worried about it, but will reach out to the dealer and see what they say.
 

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I believe my system constantly reading 14.7 volts is not operating as designed. The constant high voltage itself is not a problem as varying the voltage is done for economy and battery health, so marginal benefit. My biggest concern was a possible failing Aux battery, but I bypassed it and nothing changed. I'm not worried about it, but will reach out to the dealer and see what they say.
Jebiruph Thanks! I have to take mine into the dealership Monday, so guess I’ll have them take a look at it. I really appreciate the your help.

I will say this, it’s been very cold here on many of the days when I checked the voltage. I’ve driven it 60 plus miles on some of those days and the voltage stayed at 14.7-14.8.
 

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Don't wait until it goes bad to bypass it, if you're going to do it, bypass it while it is still good. Then if your main battery is not able crank the starter, you have a functional backup available.
I am an EE by trade. Just picked up my JLR on Friday. Looking to bypass the AUX Batt. I haven't checked for access to N3 yet...could you simply install an unfused jumper between N1 & N3 and remove the ground from the AUX Batt? BTW, Like your drawings.
 

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I am an EE by trade. Just picked up my JLR on Friday. Looking to bypass the AUX Batt. I haven't checked for access to N3 yet...could you simply install an unfused jumper between N1 & N3 and remove the ground from the AUX Batt? BTW, Like your drawings.
I don’t think N3 has anything on it but a nut but can’t say 100% for sure
 

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I am an EE by trade. Just picked up my JLR on Friday. Looking to bypass the AUX Batt. I haven't checked for access to N3 yet...could you simply install an unfused jumper between N1 & N3 and remove the ground from the AUX Batt? BTW, Like your drawings.
I’ve been wondering about N3’s function as well. It does show, in Jebiruph’s schematic, that N3 goes to the aux battery’s positive terminal. Is the PCR connected to something, like the ESS circuit?

I would most definitely immobilize ESS by disconnecting the under hood switch, then as you said disconnect the aux battery’s ground. I’m not an EE but a degreed ME.

My Jeep is in road salt season storage, temporarily out of service.
 
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I am an EE by trade. Just picked up my JLR on Friday. Looking to bypass the AUX Batt. I haven't checked for access to N3 yet...could you simply install an unfused jumper between N1 & N3 and remove the ground from the AUX Batt? BTW, Like your drawings.
That would work. The fuse does two things, it is an easy way to quickly enable/disable the jumper and, not knowing how much current might pass through the jumper, it prevents over loading the jumper wire.

Edit: Realize that by using N3 your are unnecessarily going through one of the high capacity fuses, that's why I use N2.
 
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That would work. The fuse does two things, it is an easy way to quickly enable/disable the jumper and, not knowing how much current might pass through the jumper, it prevents over loading the jumper wire.

Edit: Realize that by using N3 your are unnecessarily going through one of the high capacity fuses, that's why I use N2.
Is there anything connected to N3, it appears it’s just a nut with nothing under it
 
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Is there anything connected to N3, it appears it’s just a nut with nothing under it
N3 connects to the Aux battery through the PCR, The nut is integrated into the metal tab at the end of the cable. This video shows the N terminal cable connections.
 

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After thinking about remote area travel reliability, I realized that the bypass could also be used to bypass any blown high capacity fuse. Due to the high current rating of some of those fuses, a higher current bypass might be needed. After looking at the fuse holder in the first bypass, I simplified the design even further to accommodate for the use use of higher current components.
bypass kit 3.jpg

The new bypass just uses spade lugs to connect to the fuse contacts. This one uses 10 GA compared to the 12 GA of the original and is only rated for 40 amps due to the manufacturers rating of the terminals, but with the right terminals and wire you could get to a higher current rating. I found blade fuses rated up to 100 amps on amazon.
How about using something like this? You can get it with fuses from 40 to 80 amps using their inline fuse holder with 8 gauge wire.

https://powerwerx.com/maxi-inline-f...A6U1DzmTqS7SdGS9Pcf6nQRnOoi3_D9waAhoNEALw_wcB
 
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CanAmMick

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The crimp terminals are what limit the current rating on mine, to be safe you need to use higher rated terminals than I did.
That sounds great. Thanks so much. Have a Happy New Year!
 
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In order to select the correct Fuse size, Does anybody know or have attempted to measure the MAX Load Current on Terminal "N1"? Would be handy to know the total sum of all the down stream fuse sizes connect to N1.
 

                           
























































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