Disconnecting ESS AUX Battery to use as a backup

[RockHopper]

I just got the genesis tray and purchased isolator from hellroaring. N1 and N2 are both connected to the primary positive terminal. The IBS is connected to the primary negative terminal.

That is the set up I have moved to, given my issues during my rally competition with the stock set up!

Sponsored

 

[mazeppa]

I just got the genesis tray and purchased isolator from hellroaring. N1 and N2 are both connected to the primary positive terminal. The IBS is connected to the primary negative terminal.

I assume the oil dipstick still functions as normal, skimmed through the Genesis install video for a JL and noticed the dipstick had to be pushed over just a little to install the tray.

 

[DHP]

Hellroaring unit is solid-state. no moving parts. The genesis system uses a heavy-duty 100% duty factor mechanical solenoid.

Thanks for all the info!

 

[LaterGator]

yep, dipstick is just pushed over a bit for clearance.

 

[JT850]

I replaced the oem setup with a dual battery (genesis mount) and used a solid-state hellroaring battery isolator to isolate the batteries. The 2nd battery is a true backup. No loads connected to it unless I need it to start the jeep and it is disconnected from the primary battery if the ignition is off. When ignition is on and alternator voltage is above 13.2 volts the backup battery is charging. Flip a switch to connect the backup battery and start the jeep. I had to use it once after letting the JT sit for 4 weeks waiting on parts and time to work on it.


ESS still works but I use the Tazer JL mini to disable it. No error messages or lights.

Any issues due the variable voltage alternator? I went with a dc to dc charger to ensure my 2nd battery gets optimal charge. Just curious if your battery gets to 100% charge.

 

[JT850]

The Genesis and Hellroaring isolators operate differently. The Hellroaring isolator is solid-state and has no parasitic current draw when the ignition is off. It also completely isolates the batteries below 13.2V unless the combiner switch is closed. The combiner switch has 3 settings: combine both batteries to use the backup, both batteries isolated and backup charging (normal mode), and batteries completely isolated.

The Smart Alternator charging system is really annoying. On long trips, I have seen the battery voltage drop as low as 12.6 volts while driving. Below 13.2V, the backup stops charging and is isolated from the main battery.

I used a redarc bcdc charger. It takes whatever the alternator puts out and raises the voltage to charge voltage specific to battery type. It isn't cheap (around $400), but neither is the genesis setup.

 

[LaterGator]

My backup battery gets to 100% charge all the time and doesn't draw down when the ignition is off. My primary battery is a different story, because i have never seen it at full charge but I think that is because of all the draws on it even when the ignition is off.

I hate the variable voltage alternator. If I could replace it, with a std alternator I would.

 

[Caraholic]

I replaced the oem setup with a dual battery (genesis mount) and used a solid-state hellroaring battery isolator to isolate the batteries. The 2nd battery is a true backup. No loads connected to it unless I need it to start the jeep and it is disconnected from the primary battery if the ignition is off. When ignition is on and alternator voltage is above 13.2 volts the backup battery is charging. Flip a switch to connect the backup battery and start the jeep. I had to use it once after letting the JT sit for 4 weeks waiting on parts and time to work on it.


ESS still works but I use the Tazer JL mini to disable it. No error messages or lights.

Nice tip on the hellroar, I know an ambulance that could possible benefit,
Digging into it deeper now

 

[j.o.y.ride]

Pretty certain some Aux battery wonkiness is why my JT was dead the other day.

With the bypass on the JT, if I want to eliminate the AUX battery from the equation, but retain it in the jeep for last ditch jumping (or if it's dead, put the jumpers on it and reintroduce it to the electrical system) I plan to do this:

Disconnect AUX at both positive and negative, tape up the terminals, find a place to stash them. This keeps the battery physically in the truck for last ditch need.

Jump N1 and N2 with either a 40a fuse or circuit breaker.

If need to use AUX battery to jump and it's dead, put the jumper cables on it as it will charge faster than a dead main, and is strong enough for a start. After start, disconnect again, and let the main charge back up off the alternator.

Make sure ESS is off with JScan so it isn't trying off the main.

Is that correct or is anything else needed, or something wrong?

 

[j.o.y.ride]

No need to disconnect the AUX + cable? Just the negative?

Seems like you could just install a switch on the negative which is set to open circuit, and if needed for a start, turn to closed connection, to reintroduce the AUX for a self jump.

I have a switch that should work for that which came with my winch.

 

[Mr._Bill]

No need to disconnect the AUX + cable? Just the negative?

Seems like you could just install a switch on the negative which is set to open circuit, and if needed for a start, turn to closed connection, to reintroduce the AUX for a self jump.

I have a switch that should work for that which came with my winch.

I would try the switch and see how it behaves. Put it on the ESS battery negative cable that connects to the negative terminal on the main battery. Either it won't start, or it will give you a message that ESS is disabled because it's trying to charge the battery. I would only change the switch between on and off while the truck is turned off. Before installing the switch, you can test it by just disconnecting the ESS negative cable and see how it reacts. If you do install the switch, it will need to be turned on periodically to charge the ESS battery. The system may eventually hassle you over the 'dead' ESS battery. Without reading all the thread on the JL forum, I don't know how it responds to a prolonged discharge of the ESS battery. It may cause an issue with the 'smart' charging system constantly trying to charge the 'dead' ESS battery.

 

[jebiruph]

I would try the switch and see how it behaves. Put it on the ESS battery negative cable that connects to the negative terminal on the main battery. Either it won't start, or it will give you a message that ESS is disabled because it's trying to charge the battery. I would only change the switch between on and off while the truck is turned off. Before installing the switch, you can test it by just disconnecting the ESS negative cable and see how it reacts. If you do install the switch, it will need to be turned on periodically to charge the ESS battery. The system may eventually hassle you over the 'dead' ESS battery. Without reading all the thread on the JL forum, I don't know how it responds to a prolonged discharge of the ESS battery. It may cause an issue with the 'smart' charging system constantly trying to charge the 'dead' ESS battery.

The system does not monitor the status of the ESS battery except for a quick pass/fail test prior to a cold start and that test is defeated with a jumper installed to N1. If the battery is disconnect, it should maintain it's charge for a long time, but should be reconnected occasionally to top it off. How to monitor the battery voltage is discussed in that JL forum thread https://www.jlwranglerforums.com/forum/threads/ess-dual-battery-management.60034/

 

[j.o.y.ride]

I would try the switch and see how it behaves. Put it on the ESS battery negative cable that connects to the negative terminal on the main battery. Either it won't start, or it will give you a message that ESS is disabled because it's trying to charge the battery. I would only change the switch between on and off while the truck is turned off. Before installing the switch, you can test it by just disconnecting the ESS negative cable and see how it reacts. If you do install the switch, it will need to be turned on periodically to charge the ESS battery. The system may eventually hassle you over the 'dead' ESS battery. Without reading all the thread on the JL forum, I don't know how it responds to a prolonged discharge of the ESS battery. It may cause an issue with the 'smart' charging system constantly trying to charge the 'dead' ESS battery.

Pretty sure you can't simply add the negative disconnect without the jumper to feed the items the AUX battery was intended to feed. That's simply taking the battery out altogether which the truck won't be happy about.

I have a 40A circuit breaker coming and have a quick disconnect from my winch I can use on the AUX - line.

I can occasionally flip the AUX battery on and flip the jumper off and set it back to 'stock' and charge the AUX for a trip. Then flip the circuit for the jumper to on and the negative AUX to off to put the AUX battery to sleep again.

This toggle of on and off for AUX battery should work very well to disconnect the battery from the circuit for daily use, allow for easy topping off, and allow for reconnect on a self jump if needed.

Seems like an all around win.

Daily use: Jumper On, Aux off

Occasional charge: Jumper off, Aux on

Hopefully never needed self start: Jumper off, Aux on (same as occasional charge though for starting.)

And in dire need you can charge the AUX battery by jump which will go faster than the main, introduce it to the system via the above, get the truck started, and then put it back to 'stock' of jumper off and AUX - connected to charge both batteries.

 

[j.o.y.ride]

@j.o.y.ride

As mentioned in my earlier post, I have been running my 2018, 3.6, JL for over 2.5 years and well over 30,000 miles with an N1-N2 fused bypass jumper in place and the ESS negative cable disconnected.

Monthly, I place the Aux battery on a trickle/charger maintainer to assure it is kept charged.
I could just flick a switch I have and then drive and charge the Aux but don't bother doing that..

Never ever any issues. Never an EVIC notice... nothing. IF you did not know better, you would assume/figure my JL was just a stock JL, running with both Main and Aux... Reality is, my JL is running with just the Main and the Aux is just sitting there in case it ever is needed to be the backup start battery.

To this day my original stock, 3 yr. old, Aux battery tests fine..

As for dealer visits.... I have just over 41,000 mi. on my JL, now. Up to 35,000 mi. I did take the JL in for warranty work... Techs there all knew about my running with just the Main.

All the Techs and the Service Manager took no issue with my doing so...

I did though, before going to the Service Dept., hook back up the ESS negative cable and removed the 40 amp fuse from the fused N1-N2 bypass jumper... This way the Techs would see stock behavior, etc. from the JL.

What I plan to do, but with no trickle charger I plan to put it back to stock on occasion, disconnect the breaker on N1/N2 and reconnect the AUX.

 

[j.o.y.ride]

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!

Sponsored