Question about aux battery delete

[Blu3fan]

That's fair. I've still been debating on just bypassing the aux.

After charging the aux is solid at 12.6 so it's fine.

New battery sits at 12.8 so it's not a huge drain but .2 is maybe worth the bypass.

Going forwards I bought a magnetic float charger and plan to just leave the jl hooked up to it since I only drive it 2x a month. (Been Riding the motorcycle and soon the xj gets it's new stroker dropped in)

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[Blu3fan]

so this is odd.

Post battery replacement.

Battery is now at 12.6volts always while running.

Im very confident in saying it was around 14.2-3 before doing this cos I was watching it while driving.

I will go poke at things later today

 

[YBABRAT]

Yes, the pictures in this link are correct. This is what I did with my 2021 and my 2025. It's annoying that the extra stud is attached to the aux negative cable so you can't use it to make additional connections if you do the aux delete.

When I did this on both of mine I didn't notice any weird electrical issues on the first start up, at least nothing that doesn't occur when you disconnect and reconnect the battery.

I pressed out the stud and reperposed the stud and various aux cables

 

[AndySpill]

so this is odd.

Post battery replacement.

Battery is now at 12.6volts always while running.

Im very confident in saying it was around 14.2-3 before doing this cos I was watching it while driving.

I will go poke at things later today

I am making some presumptions here. One is that you are running only with the main battery now, and the second is that you've derived these voltage readings from what the dash says.

Either or both assumptions may be wrong. But if they are not, please appreciate that the voltage displayed in the dash is more a product of how hard the smart alternator is working to replace power lost in the battery such that larger amounts may be consistent with an aged out battery limited in its ability to accept charge, that an overworked alternator is trying to compensate for by "ramming power down its throat" while your new battery, at its new and ultimate level of efficiency easily accepts charge with less of a (voltage) push.

To rephrase this, the voltage reading in the EVIC (dash) doesn't necessarily equate to that a multimeter, load tester or ideally a shunt might calculate. And the lower readings you see may not only not be indicative of issues, but indicative of problem solved on your part.

 

[houstonstroker]

I have a 2021 with added stuff. I bought a new negative post so I could hook up my stuff.

 

[Blu3fan]

I was reading the "off road pages" voltage.

That page showed while driving it went from 12.9 down to 12.4. not once did the readout show higher than 13volts.

Prior to replacing the battery I was seeing consistent 14.3 volts on that page.
I will test voltage with the car running then I will hook back up the aux battery and test again if it's still not showing over 13 volts running on a multimeter.

I'll be out there today

 

[AndySpill]

I was reading the "off road pages" voltage.

That page showed while driving it went from 12.9 down to 12.4. not once did the readout show higher than 13volts.

Prior to replacing the battery I was seeing consistent 14.3 volts on that page.
I will test voltage with the car running then I will hook back up the aux battery and test again if it's still not showing over 13 volts running on a multimeter.

I'll be out there today

Are you experiencing any other issues than your concern with the dropped voltage on the EVIC?

You not only replaced the main battery but bypassed the Aux, correct? No good can come from you hooking up your new main battery to an aged Aux.

If nothing but this voltage number disturbs you then be content that your smart alternator is saving fuel, not pumping more voltage into a new battery that accepts charge well than it probably needs.

A higher voltage reading on the EVIC should not be equated here with a better outcome.

You may be chasing a problem that not only doesn't exist, but in your re-hooking up the Aux potentially introduces one.

Having no desire to run ESS events, keeping an Aux battery connect is apt to cause more problems IMO than any additional amp hours, otherwise unneeded, particularly with a new main battery, it provides.

 

[Mguy]

I was reading the "off road pages" voltage.

That page showed while driving it went from 12.9 down to 12.4. not once did the readout show higher than 13volts.

Prior to replacing the battery I was seeing consistent 14.3 volts on that page.
I will test voltage with the car running then I will hook back up the aux battery and test again if it's still not showing over 13 volts running on a multimeter.

I'll be out there today

This thread addresses, but does not fully resolve, your concerns.

Reconnecting your aux battery will not help with anything.

 

[Blu3fan]

Been testing
Running voltages range from 12.7 to 13.4 volts (multimeter)

The dash will show 12.4-12.6 no matter what the real voltage is.

I have unplugged the aux battery completely.
And also have a float charger on it. Permanently now
Thanks for all the documentation. Eventually I'll end up needing to know how it works.

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