When to Replace Batteries

[PyrPatriot]

What are the signs that one or both batteries will soon need replacing? If one goes bad then both should be replaced, I have read.

I dont recall the display ever showing below 14V, now it is at 13, goes up to 13.8 briefly during downhill coasting.


At just under 60k miles, late 2019 build date

ETA: I see this should be in Battery Talk

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[Mr._Bill]

The most common indicator is getting the Aux Switches or ESS unavailable messages. It doesn't mean failing batteries, but shows there's a charging issue that needs some attention. Otherwise, it's the same as any vehicle, when it will no longer start they need replaced.

 

[PyrPatriot]

Battery test at AutoZone indicated a start system issue. I suspect aux battery has failed

 

[Mr._Bill]

Battery test at AutoZone indicated a start system issue. I suspect aux battery has failed

That's very likely. AutoZone here has the AUX14 battery for $99, but it is only available at a few of the locations. The biggest hassle will be getting to it to replace it.

 

[kevman65]

The biggest hassle will be getting to it to replace it.

OP,

Less steps and less time through the wheel well. But I didn't find going through the fuse box that bad. Just a lot of things to remember to get back in proper place.

You might check your battery cable connections at the AUX battery, I had one that was loose early in the game and it showed all the signs of a bad battery but once tightened down the symptoms went away and everything charged fine.

BUT, with the date and mileage, probably due for at least the AUX. It is basically a motorcycle/powersports battery and 3-4 years is about average life.

 

[ShadowsPapa]

now it is at 13, goes up to 13.8 briefly during downhill coasting.

That's normal. When you need torque it cuts the charging rate. When slowing, coasting, etc. it sees you aren't taking engine torque and ups the charging rate. That's smart charging and has been posted about with a diagram.

3 years on an AGM is what I've been finding from the battery sellers online.

 

[Jteakus]

@ShadowsPapa , Will I be ok to delete the small battery and tie the leads into the primary battery?

 

[Mr._Bill]

@ShadowsPapa , Will I be ok to delete the small battery and tie the leads into the primary battery?

It will cause a warranty problem if you have any electrical issues. It will function okay, especially if you keep the ESS button off so it doesn't engage.

 

[ShadowsPapa]

It will cause a warranty problem if you have any electrical issues. It will function okay, especially if you keep the ESS button off so it doesn't engage.

Yeah, I'd do the Jerry thing and pull the fuse for the PCR if I was tying things together like that.

 

[bd100]

(Meanwhile, in the old days, I had an Optima red top AGM last 14 years and it was still working before I replaced it just because. Sometimes the old days really WERE better!)

 

[Jteakus]

I don’t use ESS at all. What is the PCR and what does pulling its fuse do?

 

[PyrPatriot]

It will cause a warranty problem if you have any electrical issues. It will function okay, especially if you keep the ESS button off so it doesn't engage.

From what I have read and been told the ESS works without the aux battery and pushing the button does not stop the aux battery from being used or drawing power

 

[Mr._Bill]

From what I have read and been told the ESS works without the aux battery and pushing the button does not stop the aux battery from being used or drawing power

That is correct. The state of ESS does not affect battery use or charging. Eliminating the ESS battery and rewiring to run off one battery will not stop ESS from functioning. It will create a warranty problem if you have any electrical issues. The primary purpose of the ESS battery is to keep the computers stable during ESS events. Running with the ESS on using just one battery creates the risk of the computers rebooting or halting from low voltage and leaving you temporarily stranded.

 

[ShadowsPapa]

(Meanwhile, in the old days, I had an Optima red top AGM last 14 years and it was still working before I replaced it just because. Sometimes the old days really WERE better!)

Yep - I just don't understand the short lives. I'm not talking Jeep - I got curious a year or so ago and looked up to see what vendors were suggesting for life on these batteries. more than one said about 3 years.

That is correct. The state of ESS does not affect battery use or charging. Eliminating the ESS battery and rewiring to run off one battery will not stop ESS from functioning. It will create a warranty problem if you have any electrical issues. The primary purpose of the ESS battery is to keep the computers stable during ESS events. Running with the ESS on using just one battery creates the risk of the computers rebooting or halting from low voltage and leaving you temporarily stranded.

Yes, during an ESS engine off event, the electronics run off the aux battery, leaving the crank battery to restart it. That's the time the PCR is open isolation the batteries from each other. When it starts, they are connected together again.

From what I have read and been told the ESS works without the aux battery and pushing the button does not stop the aux battery from being used or drawing power

Right - those two batteries are connected together, in parallel and only separated when the engine is off during an ESS stop.

 

[PyrPatriot]

That is correct. The state of ESS does not affect battery use or charging. Eliminating the ESS battery and rewiring to run off one battery will not stop ESS from functioning. It will create a warranty problem if you have any electrical issues. The primary purpose of the ESS battery is to keep the computers stable during ESS events. Running with the ESS on using just one battery creates the risk of the computers rebooting or halting from low voltage and leaving you temporarily stranded.

I had a user on the JL forums say he has run his for 60k miles with just the main battery (though it is aftermarket, same size I believe)

Given most of my warranties are over in 500 miles (likely have some emission related ones) electrical issues warranties ended about 24k miles ago.

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