Auxiliary Battery Delete Poll

[Remy_Dog]

I’ve gone the “muscle memory” route. Every time I press the start button I then right away press the disable ESS button. It’s a pain in the neck but as my JT is leased I may end up trading in for a Rubi if I don’t end up buying this one. Actually, I may end up buying my Sport S because I’m very happy with it at nearly a year into the lease.

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[biodiesel]

I’ve gone the “muscle memory” route. Every time I press the start button I then right away press the disable ESS button.

I do the same.

In this fast-paced world, I've found that everyone has different tolerance levels. Personally, I don't find pressing the button to be a major problem, but for others, it drives them bananas.

 

[ShadowsPapa]

I let it work, my wife really likes the feature.
I do press the button in certain driving situations, maybe in extremely heavy traffic on I80 east near Altoona where it's stop and go, or construction zones, certain other situations. Otherwise, it's always been "let it work as intended" on every Jeep we've owned with it from the first Grand Cherokee that had the feature, to our current vehicles.
I recall with our 2018 WK2 my wife came to me and said "how come my Jeep isn't shutting off at stop lights any more".................... batteries were going south. She wanted it working again. She was quite proud of her 25+ mpg averages.

 

[DankjeeP]

Cute. I'm only 58 you have no respect for your elders.

 

[ShadowsPapa]

It's not a myth. Since the two batteries are paralleled together, the auxiliary battery provides reserve capacity.

Absolutely true, as discussed in many other posts and threads here, including another recent one that shows they are always in parallel except during a very brief blip during an ESS restart. Otherwise, you have the combined capacity of the two batteries.

What is a myth is the statement:
"when one battery goes it will take out the other battery"

That should be changed to "may" or "maybe" or "might" - depending on how the first battery failed as a battery can fail in many different ways.

..but........but..but, what about all of those posts out there?
Internet lore, or scare stories, or posts by people who don't know, have no experience with multiple battery systems, or make a guess that happened to apply in THEIR particular case.
This forum is littered with many posts where JT owners have said "main battery went bad, replaced IT and moved on" - meaning the aux was fine, and lasted another year or so.
Similar for when the aux battery failed - several here have said that "aux failed, replaced it, main checked out fine, moved on.........."

And then there's my own direct experience (not only as an auto mechanic with GM electrical and battery classed under my belt) but as a person who farmed for several years. In my "down time", winters, mid-summer when the rotary hoe and cultivator was parked, I ran a repair shop. I did work for the local coop as well as local farmers and so on. Many tractors (and some trucks) had multiple battery setups. Some had 2 in parallel, some had 4 in a combo series/parallel (Massey Ferguson is an example)
When a battery failed, I didn't have to replace all or both batteries in most cases. The M-F tractor that comes to mind had one bad battery. I replaced it and the beast started right up and the other batteries were fine.
So the statement that "if one fails it WILL take out the other" is a myth. It may, but it's more often the case that it won't.
The statement "the aux will go first and take out the main" is also myth. Many posts here show that the main may go first and the aux battery is still fine, not taken out, not dead first.

But people will believe what they have seen over and over and over in Jeep forums across the web, because it's posted so often, it "becomes fact" by the virtue of so many reposts, or others repeating what they've been told.

So this is another of those "do whatever you want" but please don't go touting it as a horror story that WILL happen, or as fact.
It's your truck, if you want to do something, go for it.

It's the internet, and every passing year I see more support for my former IT boss saying the internet was the "misinformation stupid highway".

 

[ShadowsPapa]

Some will argue that the auxiliary battery is there to keep your electronics stable during auto start-stop sessions. That may be the intent, but handing off the full load of sensitive electronics to a little lawnmower battery tucked away behind a fender liner is dumber than a bag of hammers.

It doesn't do that. That's not how it works. They are in full parallel at all times except for fractions of a second during an ESS restart. Otherwise, during the stop and at all other times, they are in parallel, tied together. Both batteries share the load except during ESS restart. Only then does the main handle the starter and the aux handle other things - and that's for less time than it takes you to say MISSISSIPPI.

Spinning an engine against compression to start does draw some amps. But everything else is or mostly digital. LEDs and screens and onboard computers don't draw amps like old school incandescents and analog switching and relays. Once a vehicle is actually running, if it has a healthy and adequate alternator then the electrical system just purrs along easily.

Seems to me that the problem is batteries. Batteries do suck these days.

Another member did a quick test a couple of days ago - I assume minus the lighting - I believe he said about 8 amps. That's a fair draw. There are multiple modules, the antennas take some power.

These starters take very little power, not like years ago. They are so much more efficient it's crazy to even compare to something from 40 years ago.

You are 100% on the - once it's started, the alternator takes over carrying the load.
Yes, exactly it. The batteries just sit there. The idea is that they get topped off again and the alternator handles the whole of the system load - lighting and so on. This was the case even decades ago when we ran ammeters instead of volt meters as standard equipment. That meter pretty much stayed in the middle - meaning nothing was coming out of the batteries at all, except maybe on high beams at an idle (talking legacy stuff there)
Batteries these days do suck. I heard customers in a parts store griping that they can't get more than 4 years out of their car batteries. And yet - I've gotten 6, even 12 years, out of OEM batteries in the past! My F250 which sat a fair amount, went 12 years. My Silverado, again, it sat a fair amount, went 6 years on the GM battery. I've had lawn tractor batteries go 10 years.
Not any more. The high end battery in my SX4 lasted 4 years - and that's with a battery tender on it during winter months.

 

[Greg_L]

Absolutely true, as discussed in many other posts and threads here, including another recent one that shows they are always in parallel except during a very brief blip during an ESS restart. Otherwise, you have the combined capacity of the two batteries.

What is a myth is the statement:
"when one battery goes it will take out the other battery"

That should be changed to "may" or "maybe" or "might" - depending on how the first battery failed as a battery can fail in many different ways.

..but........but..but, what about all of those posts out there?
Internet lore, or scare stories, or posts by people who don't know, have no experience with multiple battery systems, or make a guess that happened to apply in THEIR particular case.
This forum is littered with many posts where JT owners have said "main battery went bad, replaced IT and moved on" - meaning the aux was fine, and lasted another year or so.
Similar for when the aux battery failed - several here have said that "aux failed, replaced it, main checked out fine, moved on.........."

And then there's my own direct experience (not only as an auto mechanic with GM electrical and battery classed under my belt) but as a person who farmed for several years. In my "down time", winters, mid-summer when the rotary hoe and cultivator was parked, I ran a repair shop. I did work for the local coop as well as local farmers and so on. Many tractors (and some trucks) had multiple battery setups. Some had 2 in parallel, some had 4 in a combo series/parallel (Massey Ferguson is an example)
When a battery failed, I didn't have to replace all or both batteries in most cases. The M-F tractor that comes to mind had one bad battery. I replaced it and the beast started right up and the other batteries were fine.
So the statement that "if one fails it WILL take out the other" is a myth. It may, but it's more often the case that it won't.
The statement "the aux will go first and take out the main" is also myth. Many posts here show that the main may go first and the aux battery is still fine, not taken out, not dead first.

But people will believe what they have seen over and over and over in Jeep forums across the web, because it's posted so often, it "becomes fact" by the virtue of so many reposts, or others repeating what they've been told.

So this is another of those "do whatever you want" but please don't go touting it as a horror story that WILL happen, or as fact.
It's your truck, if you want to do something, go for it.

It's the internet, and every passing year I see more support for my former IT boss saying the internet was the "misinformation stupid highway".

OMG amen.

 

[Liftr]

What does it mean? Dull men’s club just curios

It was just a tongue in cheek phrase. But, I have discovered there is a dedicated page on FB! It seems to be a repository for mundane observation and musings.

 

[DankjeeP]

It was just a tongue in cheek phrase. But, I have discovered there is a dedicated page on FB! It seems to be a repository for mundane observation and musings.

I have not and never will

It was just a tongue in cheek phrase. But, I have discovered there is a dedicated page on FB! It seems to be a repository for mundane observation and musings.

Never found a compelling reason to debase myself enough to go on that site. Hard to believe probably for a lot of people, but just not my thing.

It also destroyed some local clubs, left us in the dust.

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