A Christmas message about Jeep's batteries and charging system.

[Andy29847]

The Intelligent Battery Sensor (IBS) is not smart. It is just a sensor.

The Smart Alternator is dumb. When it is winter (cold), it just charges along at 14.5-14.7, regardless of the state of charge of the battery.

The Jeep 2 battery system is effectively just one battery. Except for a start/stop event, the 2 batteries are connected together, which geometrically increases a Jeep owner's chance for battery trouble. Very little is gained by allowing some of the cab loads to be handled by the aux battery during a stop/start event. Much is lost when the batteries get near their end-of-life. Jeep could have installed a bigger better main battery, eliminated the aux battery, and saved money.

The design of the Jeep battery and charging system make it very hard to deduce useful information from the Jeep's voltmeter. For example, if you voltmeter is reading in the 12's, you may have 2 fully charged batteries or your alternator may have taken a dump. Drive a while and find out. If the Smart alternator and IBS were really smart, we could get a dash readout on the state of our batteries both together and individually.

If Santa is keeping tabs on the engineers and bean counters that conspired to give us the battery/charging system in our new Jeeps, those guys are not going to get presents.

Merry Christmas to all, and to all a good night.

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[Hootbro]

 

[Mr._Bill]

What's that phrase, 'embrace the suck' ?

The two battery design has been around for a long time. It was purposely used, and is not going away. It amazes me how many people think they know more than the engineers who had to deal with the list of design requirements and then put it together and make it work.

 

[High Alextude]

Welp.

 

[Arcticelf]

What's that phrase, 'embrace the suck' ?

The two battery design has been around for a long time. It was purposely used, and is not going away. It amazes me how many people think they know more than the engineers who had to deal with the list of design requirements and then put it together and make it work.

Hi, I'm an engineer. I know way more about design for $MakeingPeopleHappy and $BuildingReliableTrucks than the geniuses in the accounting and pricing department who control the actual design trade space. If you let me and my friends run wild you'd have an amazing truck, it would also cost $250K to build, so you win some and you lose some.

 

[Arcticelf]

Fortunately for us, there is a very easy solution to this problem: remove the BS Aux battery, wire up the vehicle side of the wiring harness appropriately to put power where it's needed, and secure all your work.

There's a couple threads on the forum with the wiring diagram. I've been running that way with no issues since my aux battery died and killed my truck this summer.

 

[Andy29847]

I hold these truths to be self-evident as shown by the "Battery" section of this forum.

For the record, the Bronco forum does not have a battery section.

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[GeneralMaximus]

My Porsche handles ESS fine with just one battery. Im on year four on the second battery now and the factory battery was good for six years. I guess some manufacturers just know how to do it right…

 

[Andy29847]

Hi, I'm an engineer. I know way more about design for $MakeingPeopleHappy and $BuildingReliableTrucks than the geniuses in the accounting and pricing department who control the actual design trade space. If you let me and my friends run wild you'd have an amazing truck, it would also cost $250K to build, so you win some and you lose some.

your message ignores the simplicity and cost effectiveness of a single battery system. ?

 

[Lunentucker]

A capacitor could hold things stable during an ESS event, AND increase the likelihood of a serial mucker getting elctromocuted.

 

[1550jrit]

I linked my two batteries together with a flux capacitor. Whenever something goes wrong, I just jump back in time to when everything was new. 60% of the time, works every time.

 

[Andy29847]

I linked my two batteries together with a flux capacitor. Whenever something goes wrong, I just jump back in time to when everything was new. 60% of the time, works every time.

60% is a good number.

 

[Jaxmax]

Merry Christmas, my daughter dropped us off at the airport yesterday for a trip to Florida and will pick us up in our JL Wrangler on Friday….but this morning batteries are dead and it won’t start 2919 Wrangler sounds about right, strange thing is my wife had a 2010 JK ,she had it nine years on the OEM battery!….Jack

EDIT:
Oops wife just corrected me she had AAA change the battery at around 7 years when I was away surf fishing! Yup she is usually right, I’m usually wrong even when I am right!

 

[kevman65]

Rip both batteries out, tear out the floor pan and Fred Flintstone that SOB........

 

[Andy29847]

Jeep JL/JT ESS Stop/Start diagram.

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