What am I doing wrong?

[DaveK]

Myth busted. Took the negate off completely and she fired right up. Then found this. 
 

 

[superhawk996]

Ahhhh, the ole start-stop fuck you, I didn't even think about that.  I don't know how they're wired, but I assume they're paralleled so other one also went dead and is now possibly going to be an extra drain on the new one.  When a battery gets drained it'll often have a lower resting voltage and if they're wired in parallel it'll pull the new one down a bit when parked.  I think it would be a good idea to put a charger on the old battery to 'reset' it, the alternator won't do it.  Assuming it has a current sensor I think you'd want to disconnect both batteries and charge that battery independent of the system, then reconnect them.

 

'reset' meaning that a charger will raise the battery's voltage enough to probably erase most of the damage done by the deep discharge.

[DaveK]

17 minutes ago, superhawk996 said:

Ahhhh, the ole start-stop fuck you, I didn't even think about that.  I don't know how they're wired, but I assume they're paralleled so other one also went dead and is now possibly going to be an extra drain on the new one.  When a battery gets drained it'll often have a lower resting voltage and if they're wired in parallel it'll pull the new one down a bit when parked.  I think it would be a good idea to put a charger on the old battery to 'reset' it, the alternator won't do it.  Assuming it has a current sensor I think you'd want to disconnect both batteries and charge that battery independent of the system, then reconnect them.

 

'reset' meaning that a charger will raise the battery's voltage enough to probably erase most of the damage done by the deep discharge.

Thank you!!

 

I think I’m going to pull fuse F42 and disconnect the aux battery ground cable from the main battery which kills (eliminates) the aux battery all together. Then hook up the auto start stop kill switch and be done with it all. 
 

All the aux battery does is control the auto start stop from drawing on the main battery as well power the accessories that continue to run when the car is in auto stop mode. 

[SwampNut]

I have no idea what you are trying to do.  Make it not start?  I thought you just wanted to remove the primary battery for...reasons.

[DaveK]

The primary battery will charge the auxiliary battery unless you disconnect it. 

Edited August 6, 2025 by DaveK

[SwampNut]

19 minutes ago, DaveK said:

The primary battery will charge the auxiliary battery unless you disconnect it. 

 

Yes, and I still have no idea what you want to accomplish.

[Zero Knievel]

6 hours ago, SwampNut said:

Yes, and I still have no idea what you want to accomplish.

He seems to want a kill switch that will disable the whole system…to preserve the batteries.  He either needs two (one for each battery) or identify a circuit he can break that disables the whole system.  I’d need a schematic to even start to see if there is a place to do that…then see if it’s even accessible.

[DaveK]

8 hours ago, SwampNut said:

 

Yes, and I still have no idea what you want to accomplish.

Run the car off 1 battery. 
 

Disable the auto start stop. 
 

Install a battery disconnect switch. 

[SwampNut]

2 hours ago, DaveK said:

Run the car off 1 battery. 

 

WTF.

[DaveK]

37 minutes ago, SwampNut said:

 

WTF.

 

Not sure what you are asking or saying with that reply.  Challenge is...that little aux battery is located in a spot where you need to yank off the entire fender to get to it and pull or replace it.  if I store my jeep and only take out the main...the aux goes dead and then when I hook up the main the dead one draws off the main.  So, the fix (60 page thread on the wrangler forum) is a quick fix to disable it as it is not needed when you disable the Auto Start/Stop feature. 

 

 

[SwampNut]

I generally discuss things from an end goal perspective, with the reason for the end goal.  "Why do you want to transform this hotel into X class and how do we get there?"  This thread started with just a picture of a shitty part with no reason for it to be used.  I had to surmise that it was related to your past questions about battery storage.  If you care to engage in a solutions-focused discussion...what is your true, root goal here?  Why?

 

[DaveK]

2 minutes ago, SwampNut said:

I generally discuss things from an end goal perspective, with the reason for the end goal.  "Why do you want to transform this hotel into X class and how do we get there?"  This thread started with just a picture of a shitty part with no reason for it to be used.  I had to surmise that it was related to your past questions about battery storage.  If you care to engage in a solutions-focused discussion...what is your true, root goal here?  Why?

 

I’m good. Thanks. 

[XXitanium]

I don't usually read Dave's responses.

 

That one made me laugh.

[DaveK]

8 minutes ago, XXitanium said:

I don't usually read Dave's responses.

 

That one made me laugh.

 

Yep, I am all good.  I need to disconnect the AUX battery and kill the Start Stop feature to get my desired result which is not to have a secondary parallel battery (which is impossible to get to without dissembling the entire damn car) and run off 1 battery....which, based off my reading the Wrangler forum... 50% of forums members do. 

 

Did it last night...and I am ALL fixed up!!!!

[SwampNut]

What...the...fuck.  Zero moment.  Ok.

 

[DaveK]

14 minutes ago, SwampNut said:

What...the...fuck.  Zero moment.  Ok.

 

 

All good, your assistance nor criticism is needed here.  But a thank you to Oscar for helping me out and getting me started on what I needed to do. 

On 8/5/2025 at 8:54 PM, superhawk996 said:

but I assume they're paralleled so other one also went dead and is now possibly going to be an extra drain on the new one.

 

[DaveK]

For those others interested.... I'll offer this up too. 

 

[SwampNut]

No criticism, just putting the steering damper on my head and having a laugh.

[DaveK]

Good people take a different route. 

[SwampNut]

Well sure, there are much better ways to deal with the ASS feature, but I'm not sure how that determines good/bad.

[TOXXIC]

On 8/4/2025 at 5:48 PM, SwampNut said:

 

I'm not sure what is needed for a car.  @superhawk996 this should be fine for his starting current right?

 

https://www.amazon.com/dp/B07T288VN8?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_7&th=1

 

 

This is the exact unit in my RV and on my friend’s boat. 

[SwampNut]

36 minutes ago, TOXXIC said:

 

This is the exact unit in my RV and on my friend’s boat. 

 

They've been solid for me, but never used for starting current.

[XXitanium]

You could put a normally open held closed solenoid on it that when you started the car would close charge the battery. When you turn the car off, it would open up and leave the secondary battery. Unable to be drained.

[blackhawkxx]

9 hours ago, XXitanium said:

You could put a normally open held closed solenoid on it that when you started the car would close charge the battery. When you turn the car off, it would open up and leave the secondary battery. Unable to be drained.

But if he is getting rid of the start/stop (which is a great idea) he doesn't need a second battery.

[superhawk996]

16 hours ago, XXitanium said:

You could put a normally open held closed solenoid on it that when you started the car would close charge the battery. When you turn the car off, it would open up and leave the secondary battery. Unable to be drained.

Making that work would be challenging, and would be bad for the car, and possibly the driver.  Every time you kill power all the vehicle's learned stuff will go away; fuel trims, idle throttle position, shift settings, etc.  There's also a likelihood of confusing the electronics, and possibly smoking them.

 

Radio presets and other comfort/convenience settings might also be re-set making the driver re-do it all.  This will also happen when manually disconnecting the battery, but it sucks less than having it happen on every stop.  If one wanted to use a relay/solenoid to avoid going under the hood it should be manually controlled and always turned on before turning the ignition on, and turned off after turning the ignition off.

 

Many of my vehicles sit for weeks at a time, I almost never disconnect a battery.  That might be a little different if I didn't have the means to easily test and rejuvenate them.