I've kept a battery maintainer on my car 24/7 for the 2+ years it has been in care and have had zero issues. Yesterday I went to get gas at Costco [about 5 miles away], then parked in the lot to score a pizza, came back to the car and the battery was not having it. "Low battery" warning lights were on. Voltage measured 11.2v on my little plug in volt meter, so I called AAA, the guy jumped it so I could drive onto the flatbed. Back home, plugged in back into the maintainer and nailed the pizza.

This morning the voltage read 13.1v on my real volt meter and the maintainer was green [full charge]. Started the car and let it run for about three minutes, turned it off and the Low Battery warning lights came on again. The voltage meter read 12.8v. I figured after 5.5 years, the battery was done but I am not sure what was going on. Obviously the car's electronics were picking up something beyond the voltage.

As an aside, if you have a 2018 or 2019 and search for batteries, nothing seems to come up. There are all kinds of options for 2017. I called my JLR dealer and the service adviser had no idea why but said it should be fine to use a 2017 spec battery which I did. Went back to Costco and bought an Interstate H8 49, 900 CCA for $169. and put it in myself. It was an interesting installation but very do-able. The heat [100F] didn't help.

Perhaps the moral of the story is never assume your battery is ok if it's getting up there in years [even if your maintainer is blinking green and the voltage meter reading is wnl]? Anybody have any insight here? Thanks.

 

What you describe, including the short-lived effect of CTEK unit, is exactly the pattern of a failing battery. I had precisely the same experience with battery decline in an XK. Yes, it needed a new battery which I charged fully before installation. The problem disappeared.

 

In April I bought a 2021 with 6,000 miles on the clock and drove it home from MD to FL.

First thing I did was to replace the factory battery.

The date code on it was 2019 !

Furthermore, the tire codes are also 2019.

The OP mentioned HEAT.

Here in Florida, 3-4 years and it's time to replace that battery.

For my family daily driver cars and the boat, this is done before 4 years of service.

Doing this preemptively has kept me from ever having an issue on the road.

Cheap insurance, especially with all the electrically dependent systems packed on-board these cars!

BEST !

RWS

 

You got an AGM for $169?

 

Mine was $211. Also, Costco/Interstate.

Anyone who follows this forum should be fully aware that these cars are sensitive to having good, well-charged batteries. And, given the many threads about how much of a PIA it can be when they go flat, people shouldn't put off replacement - especially for a couple of hundred bucks.

 

Live and learn. I had just replaced my wife's Cayenne battery about a year ago [similar sized AGM] and it was 9 years old and still going strong. I know many people on the forum have had their batteries last 5+ years. Knowing it was going to be a somewhat arduous install, I kind of put it off, but like all things in life, it came back to bite me. Fortunately, needing a tow in a somewhat deserted part of Cosco's parking lot is about the best you can hope for, as was the AAA experience. Only took 30 minutes to arrive and the tech was super nice and really careful.

Btw, the Interstate deal at Cosco is the best around SoCal, by far.

And thanks for the responses!

 

Was something plugged into your ODBII port recently? Sounds like the classic ODBII port drain and a CTEK will only mask the symptom. If you get out of your car and come back 30 minutes later and your hazzard triangle is still lit up (it will usually stay lit up for about 10 minutes), then your car is stuck in a maintenance mode that will drain your battery to dead. The fix is to disconnect the negaticv lead of your batter for about a minute and then reconnect it. This happened to my car a few years ago after I took my car to the dealer. Four days later, the battery gave me to low message and then the next day it was dead. After performing the reset, I have had no issues since.

 

No, nothing like that although I was aware of that possibility when I did my tune a couple of years ago. Actually, no warning what-so-ever. Even when I started the car up after getting gas, there was no indication of any battery drain/hesitancy at all. I was really surprised.

 

"...and nailed the pizza."

I genuinely loved this detail.