Disabling Smart Alternator

[Dan789]

Just wondering if anyone has investigated or tried to disable the way the alternator works on the Jl Wrangler? I have put a Lithium battery in as the start battery. This battery has a management system on it that allows me to connect to an app on my phone, therefore I can watch how the battery is charging/discharging.

The biggest thing I notice is how much the battery is not charging. Unless the foot is off the accelerator pedal and the car is coasting, the alternator is generally not charging the battery.

Is this controlled by the shunt on the negative post on the battery, or it controlled by the computer?

I'm coming to really not like these modern cars full of electrics.

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[WranglerMan]

The alternator itself is not technically ”smart” the IBS module that resides on the negative terminal keeps track of the battery charging and analyzes lots of info to dictate what the alternator does, the reason for the dancing voltage is by design to reduce load on the engine and improve fuel economy.

If you get into your JL and look at the EVIC voltage display it can range anywhere from 12.8-14.3 and you will see 14+ a lot if you don’t drive a lot or possibly one of the batteries is bad or the IBS is bad.

Here is a short clip I did quite awhile back and it was done right after charging, as you can see as I decelerate the voltage ramps up and once up to a steady speed it settles down



You can disconnect the IBS and this will flag and code and give a EVIC warning that can be removed with JSCAN and doing this will force the alternator to throw 14+ volts all the time and shorten battery life by constantly charging

Here is some testing I did with the IBS

https://www.jlwranglerforums.com/forum/threads/my-testing-of-the-ibs-ibm-system.79412/

Jerry @Jebiruph did some good research here as well https://www.jlwranglerforums.com/forum/threads/3-6l-ess-ibs-information.22585/

Battery charging, and upkeep on these newer vehicles is not as simple as the old days

 

[Dan789]

Thank guys. Did a bit of research on Jscan but couldn't find anything specific to my needs.

Also looked through your post WranglerMan. Big write up. Understand that this item may be specific to the computer settings. Last night I disconnected the shunt plug and left it unplugged. Took it for a drive and didn't see any issues. Wife dropped the kids at school, no issues. Then this afternoon she went to pick them up, the steering locked 3 times and the ABS locked on.
Maybe a coincidence, maybe not. Car is at Jeep at the moment re flashing the computer to see if it fixes it.

Now, I don't believe it has anything to do with the plug not being connected, but time will tell.

The reason that I think that I am having trouble with this is that I installed a Lithium bttery that delivers a higher voltage than the rubbish battery that was in there before.
I spoke to the Jeep service guy today that suggested instead of disabling the shunt on the battery, that I should just remove the plug on the back of the alternator. This will throw a code, but I am hoping that the Tazer will be able to clear it so no check engine light will be on.

Has anyone looked into doing this?

 

[WranglerMan]

@Dan789 during my testing I did several things with the IBS, one was I disconnected it and upon starting it immediately threw a IBS error in the EVIC display and plugging back in while running the error message remained but doing a restart the displayed message went away but the using JSCAN I looked for codes and several were stored that had to be cleared, another test was I went into JSCAN and turned off two IBS settings and restarted all ECU’s and no error messages were present and a few codes were stored but easily clears and the EVIC voltage display was 14.3 volts and stayed their for the testing period (two weeks) but I chose to turn it back on as I did some additional research into battery charging and made the personal choice that throwing a constant 14+ volts at the batteries would shorten there life but by how much I have no idea.

During the two week period of daily driving with it off I never had any issues like you so it’s hard to say what caused your problem.

Here are the JSCAN settings I toggled

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