Auxiliary 12v Battery

[Spiffy]

Hmm. Does resetting the bms effect the aux battery?
My aux is sitting at 13.4 volts.
My topdon battery load tester shows no problems.
I replaced my main battery with a h7. Dealer gave me a new motor craft h6 that I'm putting in one of my other trucks and I bought an optima. That battery is sitting on a agm smart charger that puts out 20 amps. It's also sitting at 13.5 volts.
I have reset the bms through forscan, the headlight/break tec and fdrs.
The truck has 10k miles.
Still i have no interior lights and it goes into deep sleep over night even with the smart charger attached and both batteries are at 100%

What frustrates me is it has been suggested i spend 100 bucks on a aux battery that shows no signs of fault. No one can confirm that a bms reset also resets the aux.

Has anyone replaced just the aux battery and solved their issues? All I read is some have replaced both at the same time. Then I read that most have replaced the main battery and problems go away. I have.

The information about the porpoise of the aux battery comes in bits and pieces from multiple thread
Some say it's a starting buffer for the starter. Some suggest that it powers the internal voltage requirements.

I talked to my tec today and asked he didn't even know if a bms reset does anything to the aux.
It's clear that the voltage on the main battery is exactly the same as the aux. And the charging voltage of 14.2 voltage are the same on both.

Tech said the issues with the truck not installing the uodates are only with the current voltage of the main battery.

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[Spiffy]

Man a lot of us are telling you the same thing.
However if you haven’t replaced your aux battery and it’s below where it should be, then the bms reset will just relearn that your aux battery is still dead. For 70 bucks and less time than it took for you to type a dozen messages you could have your problem fixed.
If you’re using a battery charger there is a special

You haven't been reading my posts. My aux battery is fully charged and passes load tests.

 

[HammaMan]

Did you push the disable lighting button in the truck resulting in no internal lights? They won't resume normal operations without pushing it again. The button glows orange when you disable the dome lighting.

 

[Spiffy]

Did you push the disable lighting button in the truck resulting in no internal lights? They won't resume normal operations without pushing it again. The button glows orange when you disable the dome lighting.

Yes. When I start the truck the are operational. When I close the door they shut off. When I open the door they come on only when the truck is running/ready. I shut truck off , exit and close door they stay on for a bit along with my permiter lighting. Everything shuts off after a few min. If I exit the truck and lock it Everything shuts off immediately. If I unlock the truck and open the door they Don't Come back on.
I have a Bluetooth battery monitor on both the main battery and the aux. At that moment when I open the door they both show 13.2v.
Im suspicious of a faulty bms module.

 

[HammaMan]

There isn't a BMS module persay, The BCM in conjunction with the PCM control how it all functions. It seems that the BCM is responsible for the shot calling in regards to the charging. After fully charging the batteries in the truck at the same time, perform the BMS reset procedure. If they do not work after doing that I suspect you may have a forscan variable out of place. The first time you connected the truck to forscan it saved your factory asbuilt file that you will have to manually locate. I suggest saving a new copy and comparing your original file and your current file.

 

[Spiffy]

What modual? The only forscan work i did was the headlight and that was several months ago.. this nonsense started about two months ago. I haven't touched the truck as far as programing for almost 9 months.

 

[Sig Oris]

Why would you want more reserve capacity? It should be self evident, no?

I switched Aux batt chemistries to significantly increase the time before modules sleep. I've found after 10 days the BMS will stop exterior lighting but will not sleep modules / enter low power mode. I'm going to test removing the CT from the aux batt so the BMS can no longer see its current as there's been no positives associated with allowing it to see the aux batt's current flow. I suspect this to yield a welcome change as there's no need to shut off the welcome lighting with 13v on the 12v bus.

(Edit, there is a welcome lighting timeout count between key cycles, as in you only get so many wakeups before needing a key cycle to reset this. While you may not believe you're waking up the welcome lighting, it may still be triggering if the key is within 20' of the truck. On my list to look into further)

Appreciate the response.

i guess being retired and can keep the truck on a trickle charger, did this with my 22 Ranger, I’m not seeing some of the issues others are having

 

[Kodiak]

I added the larger O'Rielly aux battery and also changed the main battery to a Walmart Everstart Platinum H7. Once all were installed I put it on charge with the Noco Genius 10 and went back out after 30 minutes and it had the slow pulse green light. Then did a BMS reset and it all went well.

The hardest part was lifting these n*tbusters in and out of the truck. Getting old ain't for sissies.

The larger O'Rielly aux battery is a fairly good fit with the only thing missing is some kind of a vent port for the vent tube. However, I do need to get a longer nut for the hold down strap and I did not trim any of the plastic guides in the battery tray. This causes the top cover to not be able to be attached. It kind of "locks" in place but it is raised up about 3/4". I took some black duct tape and ran that along the front for a temp hold but it actually does not look bad at all. It is hard to tell unless you know what you are looking for. I may leave this set up and not trim any pieces so if someone/me wants to go back to the small OEM, everything will be as built.

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