Hidden battery?

[2-D]

Working on 2021 Explorer Hybrid PIU, and found an extra battery. It is located on the LH side behind the lower interior panel, behind the LH wheel well. The part # appears to be AGM-AUX1-A. The only reference I found that even shows this battery is the "Explorer-Aviator ERG 04-22-2019 Emergency Response guide" pages 2-5, and 2-6. What I would like to know is what the purpose of this battery is. Their is already a battery under the hood, so why did they decided to put this small battery in the rear of the vehicle. Thanks in advance for any knowledge on this.

 

[peterk9]

Welcome to the Forum.
I believe this question has been asked before some time ago but I am unable to find anything on it.

Peter

 

[2-D]

Welcome to the Forum.
I believe this question has been asked before some time ago but I am unable to find anything on it.

Peter

Thanks for looking. Hopefully somebody will be able to shed some light on it in the future.

 

[Mbrooks420]

It’s probably just for more reserve capacity, or for running higher load items in the rear without having to extend larger gauge wiring to the back.

 

[Dale5403]

Looking up that part number shows it is used an a number of vehicles. No explanation of it's purpose though.

https://parts.ford.com/shop/en/us/battery-and-related-components/battery-11530513-1

 

[Dale5403]

Here is a prior thread about it. 3rd battery in a hybrid???

 

[peterk9]

Here is a prior thread about it. 3rd battery in a hybrid???

Not sure how I missed that thread in my search. Thanks Dale.

Peter

 

[t9087]

That battery is for the starter when the vehicle goes from hybrid to gas.

 

[peterk9]

That battery is for the starter when the vehicle goes from hybrid to gas.

I haven't been able to find a definitive answer as to what it is for and this post seems to in some ways seems to offer a different opinion.

3rd battery in a hybrid???

My 2020 Limited Hybrid is in the shop, it kept throwing red "Low Battery Charge" warnings at startup. The techs say the battery in the engine compartment and the hybrid power battery under the seats are both OK, the 'other' battery that appears to support the electronics package has failed...

www.explorerforum.com

The document linked in the last post in that thread refers to it as an Auxilary Battery.

Peter

 

[t9087]

Took these off my screen at work. Hope it helps. This is for a 2020+ hybrid.

 

[Dennis J.A.A.]

Working on 2021 Explorer Hybrid PIU, and found an extra battery. It is located on the LH side behind the lower interior panel, behind the LH wheel well. The part # appears to be AGM-AUX1-A. The only reference I found that even shows this battery is the "Explorer-Aviator ERG 04-22-2019 Emergency Response guide" pages 2-5, and 2-6. What I would like to know is what the purpose of this battery is. Their is already a battery under the hood, so why did they decided to put this small battery in the rear of the vehicle. Thanks in advance for any knowledge on this.View attachment 425168

I'm wondering if it could be for a GPS tracking device! Keep hunting around to see what it is connected to!
Actually, I think that would be an excellent idea that I think I will incorporate into the 2017 PIU mod.

 

[peterk9]

Dennis, the function is explained in the previous post.

Peter

 

[Dennis J.A.A.]

Dennis, the function is explained in the previous post.

Peter

Sorry must have missed that BUT I still like my idea and I think I will incorporate it in the Interceptor!

 

[t9087]

Sorry must have missed that BUT I still like my idea and I think I will incorporate it in the Interceptor!

During our Hybrid training, Ford recommended not putting anything on that rear Aux battery as it could kill that small amp hour battery, or throw codes. But you can do what you want lol.

 

[Dennis J.A.A.]

During our Hybrid training, Ford recommended not putting anything on that rear Aux battery as it could kill that small amp hour battery, or throw codes. But you can do what you want lol.

I have a 2017 NO Hybrid but I just thought the idea of a hidden battery was awesome!

 

[boss377]

After almost a year of seeing the "Service System Service Soon" and other warnings, my dealer traced it to an auxiliary battery mounted in the L/H rear side compartment. It had gotten worse recently causing features to go haywire, including the exterior entry TouchPad to shut down and door handles to not respond to touch, and other malfunctions. This was the dealer's third attempt to figure this out and seems others with Hybrids are having the same issue. Upon driving my repaired vehicle, it was once again driving under battery power like it used to, and all gremlins exorcized! The improvement is obvious and fingers crossed this was the actual fix. BTW, this battery is not a warranty item.
Hope this helps other with this issue.