Auxiliary battery. Why?

[taintedsaint]

My '21JT is my first new car in a while so I'm learning a lot. Can anyone explain why Jeep uses an auxiliary battery? What EXACTLY does it do that a larger group primary couldn't do.
If I go to a Genesis dual, does that rid me of the little aux battery? Watching video on removal of aux battery to replace seems quite a pain. I guess it comes down to new technology smacking me in the face. Thanks for any input.

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[balucipher]

start stop

 

[ShadowsPapa]

There's a multitude of threads about that - and how it's wired.
It must be your first new vehicle in a while since companies have been doing this for several years - Ford, Chevy/GM, MOPAR (Grand Cherokee for at least 4 or 5 years) and the number is growing fast.

It runs the electronics while the engine is off for ESS (or ASS, auto stop/start) That way the main battery is reserved for restarting it and doesn't get drained (in theory if all things work)
Some systems are much better than others. Ford and GM are actually jointly developing new transmission technology to work along with this.

Because it's a fuel and atmosphere saver, the EPA gives CAFE credits to companies that add it to new vehicles so even if they have trouble meeting the CAFE standards, if they add this system, they get credit and are deemed as having met the mileage standards for that model year.

 

[taintedsaint]

Thanks Shadows. You're right about cars, last new was 2015 Explorer for wife but I drove a '97 TJ to 319k miles till this past May. Other cars are a 68 Cadillac and 91 BMW 735, so EVERYTHING about this Jeep is a surprise.

 

[jbehrn]

I believe my old 16 F150 had a single heavy duty AGM battery and starter for the start/stop. In my experience the Ford design and implementation was much better thought out over my experience with my Jeep. The Ford start/stop worked without issue - took my local Jeep dealer 3 times over 8000 miles to finally get it working right. Can’t say that either system saved fuel or not (never bothered to track it)…

 

[Tackett1980]

I have a similar question. My old JK I had a dual battery setup purely for jump purposes.

I had it mounted with a large battery selector switch with dual alternators. The alternators charged the Batts and if I ever ran my main cranking battery down on accident in the woods, all I had to do was flip the switch and crank the vehicle. I was wanting to do the same thing eventually with my JT because this setup saved my hind end a couple times. Is it impossible?

 

[Kevin_D]

I believe my old 16 F150 had a single heavy duty AGM battery and starter for the start/stop. In my experience the Ford design and implementation was much better thought out over my experience with my Jeep. The Ford start/stop worked without issue - took my local Jeep dealer 3 times over 8000 miles to finally get it working right. Can’t say that either system saved fuel or not (never bothered to track it)…

I drove a F150 EcoBoost from that era, and hated the auto start/stop system: the start lag was horrendous! My JT works much better: by the time I get my foot off the brake and to the accelerator, it's running & ready to go.
And even if it didn't save fuel (which it does,) it would reduce emissions.

Kevin

 

[jbehrn]

I drove a F150 EcoBoost from that era, and hated the auto start/stop system: the start lag was horrendous! My JT works much better: by the time I get my foot off the brake and to the accelerator, it's running & ready to go.
And even if it didn't save fuel (which it does,) it would reduce emissions.

Kevin

Sounds like we had exactly the opposite experience! ?

 

[Cianalas]

I have a similar question. My old JK I had a dual battery setup purely for jump purposes.

I had it mounted with a large battery selector switch with dual alternators. The alternators charged the Batts and if I ever ran my main cranking battery down on accident in the woods, all I had to do was flip the switch and crank the vehicle. I was wanting to do the same thing eventually with my JT because this setup saved my hind end a couple times. Is it impossible?

You can wire in a second battery, though under-hood space is a little tight. There's also systems like the Genesis Dual Battery setup that have a smart cutoff to try and save your cranking battery, but also have an override button to link the two together if you need it.

 

[j.o.y.ride]

Because Jeep knows we like taking things off that they put on

 

[Tackett1980]

You can wire in a second battery, though under-hood space is a little tight. There's also systems like the Genesis Dual Battery setup that have a smart cutoff to try and save your cranking battery, but also have an override button to link the two together if you need it.

lord 600 bucks? I did mine for like 120-150 dollars and the bulk of that was wire and the battery selector. Not counting the other alternator. Why is this so expensive?

 

[Kevin_D]

<snip> Why is this so expensive?

'Cause, Jeep.

 

[Cianalas]

lord 600 bucks? I did mine for like 120-150 dollars and the bulk of that was wire and the battery selector. Not counting the other alternator. Why is this so expensive?

If you find a location for a second battery, you can still do it yourself for cheap. I can't claim to know why the Genesis is so expensive, but the extra technology in it as well as the design time to make it a nice clean install will definitely raise the price up above buying a generic switch kit and stashing the battery wherever it'll fit.

 

[Tackett1980]

If you find a location for a second battery, you can still do it yourself for cheap. I can't claim to know why the Genesis is so expensive, but the extra technology in it as well as the design time to make it a nice clean install will definitely raise the price up above buying a generic switch kit and stashing the battery wherever it'll fit.

Ive been considering using a small truck box and mounting it in the box in the bed….

if that ever happens I’ll post a build thread.

 

[cecaa850]

They use a single battery on the Durango and Grand Cherokee. Don't see why they couldn't do it with the Gladiator.

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