I have the same car. You can disable the nuisance auto/start/stop from the console, but you have to do it every time you turn on the engine. Not sure how the aux battery fits into the picture if the system is disabled.
Original cheap undersized battery is dying. It seems premature. You must have bought that car last December 30 2023 (I assume you already have it). Itās at least three years old, maybe four depending on build date, and you have no idea what the previous owner did to the car. They may have run the battery down and weakened it. Have a real garage check the car over, but Iād expect that the real problem is that junk battery Stellantis installed.
The OP has posted that they have a new battery and it has solved their problem.
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Is an auxiliary battery like this becoming a common thing? Iāve never heard of it before. dhallis (above) might be referring to the original main battery. It has not been replaced.
This might be, or could be, discussed at allpar.com, a site that specializes in Chrysler and its related brands of vehicles.
It is for the Start/Stop function, it has been mentioned in several post hereā¦ It is not just a Mopar thingā¦
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One advantage of a hybrid - it has a huge battery and electric motor handling the stop/start feature, itās seamless.
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Thanks, but that carbase.co.uk article doesnāt go into detail about the technology behind the start-stop function - no mention of an auxiliary battery, for example.
A Chevy Cruze I rented in Texas a few years ago had the feature. It worked smoothly and seamlessly. I never looked under the hood, and just assumed it was just using the carās regular 12V battery, with possibly a more ruggedly built starter motor. Why add the complexity of a small aux battery?
This Chrysler van with aux battery is the first Iāve heard of starting problems with the feature. Problems, mind you, not irritation.
I put some batteryās (both batteryās) in Jeeps with the start/stop function back in 2018, and the vehicles were already out of warranty, so it has been around a whileā¦
I donāt know try googleā¦ lol
Sorry I got bored and didnāt watch the videos completelyā¦
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It seems that start stop has been around for a very long time, imo it is nothing more than a stepping stone to hybrids/EVs, at 1st for the vehicles, now more for the drivers to get used to, at minimum, hybrids to full on EV vehicles, just like the computer controlled carburetor was to fuel injection, just something to keep EPA off the manufactures back a littleā¦
And yes I know there is much more to the storyā¦ lol
This is also the first Iām hearing of this āsmall battery to power the automatic start-stop functionā. Surprising, b/c with a two-battery configuration, it seems like youād want to use the bigger of the two batteries for the start-stop function, b/c the starter motor is usually the largest current draw in the carās electrical system. But maybe theyāve figured out how to design a speciality small battery that can supply a very big current, but only briefly, enough to crank and start the engine a few times before it needs a recharge.
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It sounds like the little battery can drain the big battery if it is bad. Would be interesting to see if you could just disconnect it without the computer going nuts.
I had two batteries with my diesel. If one went bad, you needed to replace them both. Used 24 volts for starting is all. But just disconnecting didnāt seem to be an option. Several times needed to replace both at in opportune times.
Edit: I guess I had 12 volt starter with two. Batteries providing double cca.
Your batteryās were run in series??? I thought and everyone I have seen (in modern times for automobiles) they were run in parallel, meaning 12V but twice the ampsā¦
Youāre probably right. Just what I was told back then but probably just needed more amps. Otherwise couldnāt figure out how theyād do the circuitry.
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It wouldnāt be unusual to connect two batteries in series to get a higher voltage to power a starter motor. One advantage, a starter motor designed to run on 24 volts would be a little smaller & and lighter than one using 12 volts.
That might explain the second battery - to provide 24V to a smaller, lighter starter motor.
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I think I conceded it was 12 volt starter just needed more amps. Back in the 80s that dang starter cost $300 plus installation. So donāt think it was lighter or smaller.
I have never seen a passenger car or light truck with 12 volt batteries wired in series.
Even diesel?
Diesel pickup trucks have batteries wired in parallel.
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I find no difficulty finding 24 volt starter motors available for sale on car parts websites. If they arenāt being used for passenger or light trucks, what are they being used for? Industrial machinery?