Start/Stop battery is STUPID!

[Caspien]

I've found not all chargers seem to deal with really low batteries, or they react as if the battery is charged, when it's not but isn't in great health, either.
Some it takes something with some real push - like 20 amps - to make things happen.

Drove my JT to church and back tonight (guess the destination won't matter LOL) - 26 miles each way. It was running in the low 14s for a while, then dropped into the low 13s for most of the trip. When letting off the throttle, going down hills and so on, it ramped back up to 14.1-14.2, then when I was cruising or needing power, it dropped back again to 13.1 for example.
In other words - working perfectly.
Battery voltage (with things fully connected, but truck off) at about 12.6. If I removed the parasitic load or the thing went to sleep and no fob was nearby, it would probably read closer to 12.7 with NO load at all.

Drove for about an hour tonight (was actually at a stop light when I responded to the last message from Hootbro), and while it started at 14.2-14.3, it eventually came down and sat at 14.0, and even 13.9.

That said, by the time we got home, after shutting off the system, it was still only reading 12.4.

Honestly wondering if my dash cam, with it's 'always on', power, isn't shutting itself off when it's supposed to. (12.5) So, pulled that power tonight, to see if it drops further by tomorrow morning.

I still suspect one or both of the batteries are on their way out... But, that's why we carry jump packs/hotshots with us, right

As for the comment about your situation being similar with the batteries, I suspect it's a Midwest thing.

Rural IL, north-ish from St Louis, here... and while our local jeep dealership is awesome, with a lotta jeep heads working there, thats about the extent of it... Tons of flooded batteries available, with very VERY little AGM, and no lithium at all.. short of special order.

Wife actually told me, tonight, that I should just go ahead and order the full Genesis system (she's actually talking about the Omega, shockingly) with batteries... Just so I stop OCDing.. lol

That said, when I told her, I couldn't do it in good conscience, due to the fact I'd have a hell of a time getting the next round of batteries... She just sighed and walked away. *Chuckling*

Think I'm driving her nuts, at this point.. with the crazy incessant research and pricing.

Ah well... We'll see what tomorrow brings... Maybe we'll have won the Powerball.. and I'll be able to stop OCDing... not that I'll know until Monday, since I left my tickets at the office. Lol

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[MT1]

HA - comparing a brick to an arrow. Funny stuff.

The BCM should know the voltage at rest, before the user does anything. A competent software team would handle the failures caused by low voltage gracefully and before failure, not dramatically during total failure of the vehicle like the OP described.

They planned enough for telemetry sends and license checks to have two LTE antennas for the 2023 8.4 head unit. There is one on the roll-bar and one above the left knee speaker that requires a terminating resistor if disconnected. That is redundancy, and a PITA for anyone wanting to remove it, for something the user probably will not care about. Telemetry data is something someone at Stelantis really cares about.

If, at least with the 8.4 head unit, the BCM is always on and sends telemetry twice a day, they could alert for low voltage before failure. They get the tire pressures and remaining oil life, mileage, and unknown other data points. Voltage is there.

Considering how little Stelantis pays for bug bounty, they probably just do not care about quality software overall, because Chief * Officer says so. Been there, did that, hopefully never again.

 

[Mr._Bill]

There's no direct warning about low voltage, but there are some alerts.

At each startup, the Aux Battery is separated from the Main Battery and a voltage reading is taken. If it is below a certain point, the Red A shows up along with a ESS Disabled message.

When the voltage level is low, it will show Charging, ESS unavailable or Aux Switches unavailable. If the batteries are still in decent condition, the message will go away after driving a while.

When the voltage level drops too low, the Remote Start feature doesn't function.

The biggest killer of batteries is letting them sit and discharge. If the truck is not driven enough to keep the batteries charged, it needs to have a battery maintainer connected when parked.

The OEM batteries are not the best quality. If they are kept charged, they can last up to five years, especially in a milder climate. For many, the life expectancy is usually about three years.

On my first truck, the Main Battery lasted 39 months. The Aux went about six more. It died in a state that didn't drain the Main, so it didn't get changed for about six months. I've had my current truck about 18 months. I don't expect a long life out of these batteries. It has sat a lot this summer without being driven, and I have not taken the time to setup a battery maintainer for it.

 

[ShadowsPapa]

The BCM should know the voltage at rest, before the user does anything. A competent software team would handle the failures caused by low voltage gracefully and before failure, not dramatically during total failure of the vehicle like the OP described.

You are assuming batteries fail slowly and gracefully - and never suddenly. My last battery experience was when one failed pretty instantly. The car started fine, voltages - fine. Cranked over fine, started quickly, indicating there was enough to fire the ignition system and injectors.
Drove it around to the other end of the garage into the driveway, shut it off, when I went to restart it - it was dead. It would charge up again to 12.6 (correct for a flooded lead acid battery), but once any load was put to it, the voltage dropped like a rock to about 8 or 9, with no capacity to run anything.
So in minutes, it went from ok to dead.
Any measure of voltage would have shown over 12 volts.
Batteries fail in many different ways. Some slow, some fast, and some give plenty of warning, some little.

And then you get into the driving public - think of the majority of owners, not yourself............ heck, even some forum members admit to driving with the CEL on, or that their wife told them of a light a while back and that's ok, we'll drive it anyway.

Some of us have talked of the warning signs over and over and over for years here - and guess what............ yeah, people are shocked when there's a problem.

 

[MNWillys]

Some say, and there are videos about it - going in through the right wheel well is easier. Crank the wheels hard left, take out a screw and a couple of retainers, pull out the rear half of the fender liner and swap it out from there.
If you've gone through two - there's something going on.
Has the main battery ever been properly tested?
What sort of voltage do you see at the battery when the truck is just sitting, off?

I didn't even have ONE replaced in 3 years - you have something going on....... maybe the truck sits a lot? Only short drives?

I can see trucks sitting and heat and cold being the issue. My ESS stopped working about a year or more ago. Guess the battery is dead, but never got a battery warning light. When I click on the ess button nothing happens but the light on the button lights up and once in a while I’ll get a noting that says start stop not available. My battery is always at 14.4-14.3.

 

[Charles 236]

This has probably been answered, but what happens to the AUX battery if the ESS is turned of with Tazer and it never comes on? Is that when the battery finally craps out or is it because it's being used?

No change, the batteries are wired in parallel.

 

[Maximus Gladius]

Unless you are married to having a ESS function, just do the full delete mod and you can stop worrying about it.

Looks like you reached in and grabbed its little heart and entrails and threw in on the ground. That’s pretty savage man

 

[ShadowsPapa]

Looks like you reached in and grabbed its little heart and entrails and threw in on the ground. That’s pretty savage man

Canadians would never do that - it attracts BEARS.

 

[Hootbro]

Looks like you reached in and grabbed its little heart and entrails and threw in on the ground. That’s pretty savage man

There was carnage. Not for the timid.

 

[ShadowsPapa]

Sort of like when I removed the emissions controls and simplified the wiring in my SX4 engine bay......in preparation for the 4.0

 

[Chasm]

There was carnage. Not for the timid.

Is removing the fuse box as scary as it sounds? (considering the panicked warnings I got when I stumbled onto some canbus wires in the back wall)

Is it easier to remove the battery this way or through the wheel well? Bolts at least seem more reusable than those plastic rivets.

 

[Hootbro]

Is removing the fuse box as scary as it sounds? (considering the panicked warnings I got when I stumbled onto some canbus wires in the back wall)

Is it easier to remove the battery this way or through the wheel well? Bolts at least seem more reusable than those plastic rivets.

If you are replacing the aux battery, through the wheel well from the bottom is easier and less risky of blowing the fuse array. Top down through the fuse box you just have to be more careful.

Edit: For anybody doing a full removal wiring and all, the battery tray has to come out but it will not come out if the aux battery cover on the bottom side is not first removed also.

 

[Xx~007~xX]

the quick fix for me was to jus tdisconnect the aux battery (several youtube videos on it) and then installed the Tazer Mini and turned on the "remember what the auto start/stop is set to on or off"

 

[ShadowsPapa]

the quick fix for me was to jus tdisconnect the aux battery (several youtube videos on it) and then installed the Tazer Mini and turned on the "remember what the auto start/stop is set to on or off"

Don't need the videos - there are great instructions here in several places on the forum about how to disconnect and pull F42. No big deal. Just have to be sure to disconnect the correct cable since there was a change some models years back. 2020 would be different than 2023 for example.

 

[Chasm]

the quick fix for me was to jus tdisconnect the aux battery (several youtube videos on it) and then installed the Tazer Mini and turned on the "remember what the auto start/stop is set to on or off"

It does seem like the whole poorly executed setup went something like this:
-Let's add A.S.S. to claim we're saving the environment!
-Oh crap, now we're stressing the shit out of the battery, we need more capacity, but a bigger battery won't fit!
-I know, let's just add a second smaller battery wedged into an awkward location and without any of the circuitry of a normal dual battery system!

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