Easiest Access to replace Auxiliary Battery

[Austin23]

I know there are lots of various opinions and videos on the easiest way to access the auxiliary battery but I figured I would offer my own experience in case it's helpful to anyone. My ESS died about 3 months after purchasing my brand new 2020 JL and like most of the Jeepers I know, I was fine living without it. I consider myself "below average" mechanically inclined and the thought of removing the fuse box or taking off the fender to replace the aux battery seemed more trouble than it was worth. The early videos showed the easiest way was to remove right front tire and fender. But I kept watching videos and found one showing you only needed to remove the right front tire and fender liner, without removing the entire fender. Then someone commented that you didn't need to remove the tire just turn it full lock. Then another comment said you don't even need to remove the full fender liner you just need to partially peel it back.

I have a 2020 Rubicon with 35 inch tires and a 2 inch lift and I can confirm that all you need to do is turn wheel full lock to drivers side, remove about 5 pins and 1 fender liner bolt then partially peel back the fender liner. That gave me more than enough access to replace the aux battery without any issues. Tools needed: 10 mm socket, 4 mm socket for battery posts, 4 inch extension to access the bolts, pry tool to remove rivets, and a rivet hand gun to replace the rivets. Parts needed: replacement Aux battery and replacement plastic rivets.

After 4 years, my ESS finally works again. Yes, I'll mostly turn it off, but it's nice to know it works.

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[Pirate63]

Good to know. I’ll probably be heading down that path soon.

 

[bd100]

I did the wheel turn and fender peel approach as well, but in almost freezing temps and semi-wet conditions the night before it was about to hit sub-zero temps. I did it without climbing under the vehicle, but it was miserable trying to get that battery back up into the correct position at arms length and hold it there while starting the first bolt.

Next time I'll probably install:
Genesis Offroad Stock Battery RELOCATION kit

(And hopefully in dry and warm conditions.)

 

[Valpo Jeep]

If it died 3 months after purchasing your Jeep new it would have been covered under your warranty. Should have had Jeep do it for free.

 

[Austin23]

I did the wheel turn and fender peel approach as well, but in almost freezing temps and semi-wet conditions the night before it was about to hit sub-zero temps. I did it without climbing under the vehicle, but it was miserable trying to get that battery back up into the correct position at arms length and hold it there while starting the first bolt.

Next time I'll probably install:
Genesis Offroad Stock Battery RELOCATION kit

(And hopefully in dry and warm conditions.)

LOL.. Agreed. This "easiest way" is still a hassle. I'm 6'3" with long arms and still needed to lie on support to give me enough reach to lift the battery into the correct position and thread the bolts. I will definitely consider the Genesis relocation kit the next time the aux battery fails. I would be interested in seeing a detailed install video before attempting.

 

[Valpo Jeep]

As for the relocation kit. The Jeep is 4 years old now and the battery will go bad in 2 or 3 years and then who knows how long after that to change it out. You will likely be looking to sell or trade at that point, just not worth spending $$ for the relocation kit at that point in time.

Personally I can’t fathom spending $300+ on a relocation kit that will take a few hours to install to save an hour of labor. You still have to buy a second battery with it as well. I think it would be better to just disconnect it and bypass it if you don’t like the ESS system

 

[VKSheridan]

After replacing both of my batteries twice, I gave up and eliminated the auxiliary battery altogether. I’m all about reducing emissions from idling but not at the cost of filling landfills with lead and acid Every other year from going through batteries. It’s friggin’ shameful at best.

 

[Stetson]

I have seen this approach from coming thought the side to change the battery. I guess it is my age coming into play, I just find it easier to work standing up so when I replaced mine I came through the top, removing the fuse box etc.

I didnt think it was that big of a deal to be honest . I replaced both batteries in about an hour

 

[Fuel Fire Desire]

Either way in will take about the same amount of time. I go in from the fender, just because I don’t want to pull the PDC apart and risk damaging it if there’s a less invasive way. When the PDC is split apart, it’s a bit delicate.

Holding a 8 pound battery at arms length on your back while you struggle to disconnect/ reconnect the short cables is a hell of a workout though.

 

[Stetson]

Either way in will take about the same amount of time. I go in from the fender, just because I don’t want to pull the PDC apart and risk damaging it if there’s a less invasive way. When the PDC is split apart, it’s a bit delicate.

Holding a 8 pound battery at arms length on your back while you struggle to disconnect/ reconnect the short cables is a hell of a workout though.

There are definitely pros and cons to each method. The cons for going through the wheel well is I just don’t think I can do it

 

[Fuel Fire Desire]

There are definitely pros and cons to each method. The cons for going through the wheel well is I just don’t think I can do it

You do have to be destructive and destroy the plastic pop rivets, but a new bag from Amazon is about $10, and no special tools were required. Just put a small box end on the head, and pull the stem with pliers until it breaks off. Pretty easy. The reaching with a battery in outstretched arms was the hardest part.

 

[cram501]

You do have to be destructive and destroy the plastic pop rivets, but a new bag from Amazon is about $10, and no special tools were required. Just put a small box end on the head, and pull the stem with pliers until it breaks off. Pretty easy. The reaching with a battery in outstretched arms was the hardest part.

I found just removing the fender was easier. You need to replace one push pin and possibly any clips that break when removing the fender. I thought it easier than popping and replacing the rivets. Push pins and clips are also inexpensive on Amazon or Quadratec.

 

[Austin23]

Update.. Sad to report that one week after I replaced the aux battery, both batteries ended up completely dead and wouldn't take a jump start. After reading similar stories, I have to assume this is because the new aux battery wasn't fully charged when purchased and somehow ended up draining the relatively new main battery. Others on here have warned to fully charge the aux battery before installing, so I would also highly recommend doing that. In order to jump start it, I had to bypass the aux battery by removing fuse #42 and taping off the negative aux terminal at the main battery. As many others have done, I'm going to leave the aux battery bypassed for now and just run off the main battery.

 

[Rhinebeck01]

Update.. Sad to report that one week after I replaced the aux battery, both batteries ended up completely dead and wouldn't take a jump start. After reading similar stories, I have to assume this is because the new aux battery wasn't fully charged when purchased and somehow ended up draining the relatively new main battery. Others on here have warned to fully charge the aux battery before installing, so I would also highly recommend doing that. In order to jump start it, I had to bypass the aux battery by removing fuse #42 and taping off the negative aux terminal at the main battery. As many others have done, I'm going to leave the aux battery bypassed for now and just run off the main battery.

Something to consider....

If N3 in the high amp fuse array is blown, the alternator will not charge the Aux battery.

.

 

[Austin23]

Aha.. That would make sense Rhinebeck01. And explain why this didn't happen when the old aux battery was in place. The computer went nuts when I tried to jump start it, with dash lights flashing warnings etc, so I know something was definitely not right. I'll have to try replacing the N3. You are referring to the main fuses held in place by bolts lined up next to the power distribution box, correct?

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