Disconnecting ESS AUX Battery to use as a backup

[j.o.y.ride]

My truck has never gone into start/stop after setting both to disable on JScan. I know their documentation says the hood switch needs to be disconnected but their whole thing is still in beta and hit or miss.

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[j.o.y.ride]

@j.o.y.ride

Multiple posts on Facebook and elsewhere of negative issues with JSCAN and StopStart disable.. battery related issues.... so watch out... 8-) I would not trust it... Just be sure you keep StopStart use limited to no use at all.

Interesting. Well I only just recently changed the setting, after my battery issues. And it's never even tried to turn on.

What issues do people have?

 

[jebiruph]

Here's the diagram I drew out. There's a lot of fancier ones out there but this made more sense to me.

Stock configuration you have the main feeding the 2-8 terminals and the auxillary feeding terminal 1.

The aux is pig tailed to ground via the negative block on the main battery. This is why removing the negative block from main doesn't reset the ECU, AUX will still be pigtailed to ground.

Step one is to break the ground between aux and main. You can simply disconnect and tape up or introduce an on/off switch.

Even though Aux + is still connected at block N1 it isn't getting any power to N1 because it now has no ground.

So in order to feed power to N1 you can either jump N2 to N1 or Main to N1, both via a 40A fuse or as I would prefer, a 40A breaker so you can flip on/off and you don't need to carry extra fuses.

So when the Aux negative is set to OFF and the fuse or breaker is ON you have power to N1, truck is happy, and AUX won't cause any problems... but you do need to disable start/stop via JScan etc. or you will drain your main.

Every month or so you can reconnect AUX negative lead, pop out the fuse or circuit, and it is back to stock configuration to make sure AUX stays charged.

Now the cool thing is, when you maintain your AUX charge and your main unfortunately goes dead... take the fuse out (or open the circuit breaker if you used one), flip the negative AUX lead to 'ON' and if you have kept your battery charged your AUX will start your truck. Self jump start!

You are missing a significant amount of the circuit. The starter is wired to the main battery positive terminal, so how does the aux battery get to the starter? Those fancier diagrams probably include the PCR and related cables that come into play.

 

[j.o.y.ride]

You are missing a significant amount of the circuit. The starter is wired to the main battery positive terminal, so how does the aux battery get to the starter? Those fancier diagrams probably include the PCR and related cables that come into play.

Im not trying to draw the entire thing out, just the parts that matter for a bypass. All the other stuff that stays connected either via main or is reconnected via the N1 jump is not relevant to why it works.

It's an attempt to simplify it for common folks like me who aren't electrical engineer types.

 

[rubiusgladius]

What I do:

buy a 6 inch jumper with ring terminals and a 30 amp fuse run between them. I bought 8 gauge wire.

This is for warranty concerns and keeps things intact and not excessively modified. And it’s cheap

If the Jeep sits for more than 2 weeks, I keep a battery tender hooked up to maintain aux battery and main battery.

I keep the jumper in the glovebox in case the aux battery takes a crap. If so, Then install jumper and run ESS or not off main battery until you can replace the aux battery.

the aux battery is worthless for hard loads and doesn’t provide any sort of worthwhile “backup” it’s a 12 amp hour motorcycle battery.

I have a Tazer and the ESS disabled. That said, as long as you maintain the aux battery it should not have any issues. Until it goes bad. And if it’s not getting pulled on all the time, and maintained, it should last a while. Which in that case I have a spare in dry storage

the ESS is there and probably a good idea to keep intact. This is just a work around if you have it in your life and it strands you.
and for those that think the ESS is beneficial in any way, it was a major hurdle certifying the Pentastar for 150,000 mile objectives on life. It’s best for longevity alone to NOT run it

why Jeep takes a vehicle that’s meant to go into the toolies and have it rely on a motorcycle battery to be able to start amazes me

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