What's the typical lifespan of the battery in these cars? Mine's a Jag brand, guessing it's original, and at 7 years should be at the end of its usefulness.

After sitting overnight, I measured 12.1 VDC, and going by this lead acid age chart, looks like it's getting worn. Wonder if that's contributing to some of the gremlins I've been experiencing.

 

I'm not sure, but I think mine is original, and the car is 10 years old. So far no problems at all electrics-wise, (knock on wood !!)

 

It's dead. Swap it out.

 

Battery life as determined by the manufacturer is on the battery. The battery is dated. If you live in a normal climate?? 70deg low humidity, no heat, no winter battery can last 8 yrs or longer if check and fluids maintained. Sealed battery will last same. Lithiums twice as long. Best bet on any battery and you live in mixed climate 5 yrs. safety factor if you don't want wife calling triple A.

 

I don't know. The Battery on my 1992 pristine series III Canadian limited edition V-12 Black Cherry was twenty years old when I lost the car in an accident in 2011 (Woman tee boned me on the way home from a car show). Anyway the battery was the original Lucus Battery that I kept hooked up to a battery tender when not using the car. Never showed any evidence of losing power.

 

In theory you swap the battery every 2 years
In practice, when needed

Just remember you can have a battery the cranks and starts the engine perfectly well but you get really strange happenings from the modules.

On my 04 XJR one of the first indications is the key fobs.
The FEM will loose key programming, if I reprogram the key it may work perfectly well for a few months then happen again. Once the battery is replaced it wont happen for a few years

On my last battery replacement I chose an optima battery rather than a stock replacement. Time will tell if that is better or worse. Its lighter though

Cheers
34by151

 

Your battery is a ticking time bomb. It could fail at any time. I would never in my wildest dreams leave a battery in service that long.

If you have to do it every two years, you are buying junk batteries or something is killing them.

To each his own.

 

I'd agree that Jaguar batteries are dated. The manufactured date is stamped on the negative terminal post as WW-YY where WW is the Week and YY is the Year (this one was manufactured in the 23rd week of 2012):



However, I've never seen anything on a Jaguar OE battery, the packaging or the accompanying documentation to indicate end-of-life date.

Graham

 

And I am looking for a new one.

WalMart has a direct replacement for $106.
Beats 240 from other places...

I might bight.

 

Thank you all for the great info! And thank you Graham for the date code info. I will check on that first thing, and add a battery to my list of to-do items if it's not recent.

Oh yes, I figured there won't be an end-of-life date, was just wondering what the warranty period was on these OE batteries. On my previous car the AC Delco battery was a 7 year warranty type, and just a few months over the 7 year mark I got in one morning and it was dead as a doornail. No tell-tale, car drove fine the day before, next morning absolutely everything was dead.

 

Well, not really. I have it tested regularly at a local and reputable battery shop and the last time it was OK. BTW I don't need the car every day for work as I'm now retired.

 

34by151 like the idea of running an Optima, I have used them in Landrovers before. My wife's XK will need a new Battery soon so will look into this. What color Optima are you using?

 

Mine's got 0906 stamped on it (March 2006), so definitely the original battery. I think I will feel much better once that is replaced!

 

The original in my 04 lasted 7 years. I replaced it with an Interstate. Lead acid batteries go down fast when they fail.

I stand by what I said about 10 year old batteries.

Johnson Controls makes the vast majority of the quality batteries sold in the US.

 

Its a yellotop

Cheers
34by151

 

There's quite a range of opinion through this thread reflecting differing experiences with battery life.

I've checked the invoices for replacement dates on my current and last three Jaguars (2 x XK8, XJ8L and X300) and confirmed all have been replaced at between 5 and 6 years old.

There's definitely a pattern here. As my driving habits haven't changed (all have been used as daily drivers), battery life must be closely related to use and probably climate as far as temperatures are concerned. This could explain the different experiences described in the posts here.

I keep another car for limited use which has a battery tender attached. The sixteen year old battery is still in good health.

Graham

 

I normally figure a battery is on borrowed time after 3 years, with 5 being average. That said, when my '05 turned 5 I opened up the boot to get an idea of what was in the car. Guys, this battery is huge! It's at least twice the size of my XJS battery. I am now at 8 years. The car sits for several weeks between uses, so if the battery was weak, I'd know it.

So far it is still going! I think it's way oversized for the application, so assume it will last longer than most. Deep discharge is what kills lead acids.

Also, 12.1 volts is low, but could also be discharged. Charge it with something other than the car alternator and then check. If still low, it's the bat. If it comes back up to 12.6v resting, then your charging systems at fault.

 

XJ's are very sensitive to the condition of the battery.
Well to me more accurate the various computer modules are sensitive
While it may crank perfectly it may still be marginal

If you connect up to the SDD and the battery condition is not Green, replace the battery, simple as that.

There is also a long winded test procedure in the JTIS. If you read that carefully you will work out that a battery that will pass a regular battery tester will often fail this procedure as the loads and voltages are higher in the JTIS tests than a regular battery will use.

Simple rules of thumb
1. If SDD shows yellow or red battery, replace the battery
2. If you get and weird things from the modules like losing key programming weird codes ect, replace the battery. From my experience the driver door module and the rear module are the first to show signs

Note the biggest things that determine the battery life are;
1. Vibration causing the breakdown of the plate mountings. This is why the optima spyral design is so good
2. Charge cycles. This is two fold the more starts the quicker it breaks down. The opposite is true with few starts but a long time between charges.
So a lot of stop start driving is bad for the life of a battery as is a car in storage or one with little use.
3. Temperature. This alters the resistance of the battery. This means both the discharge and charge rate change. Its quite easy to exceed these both with extremes of temperature. Added to this the effect of the number of charge cycles mentioned in "2"
4. The quality of the battery

So the upshot is depending on where you sit regards use, temperature, vibration and quality is how long it lasts.

Best advice divide the battery price by the years of the warranty. So you are now comparing the price per year of warranty then get the one with the best price and be prepared to change it after the warranty expires. If it fails before then its free, but watch out the replacement battery warrany often expries on the same date

Cheers
34by151

 

Most battery warranties are free first year only....after that they are prorated, but only against the non-discounted price. In reality, after 3 years the warranty is useless, as you can usually find the discount battery for the same or less.

34, what you say verifies that the XJ8 batteries should last longer than most...they sit in the cool boot, have little vibration with our jag air-ride, and are under loaded since they are oversized. Bonus!

 

Very important never let the battery discharge completely. As far as i know run down battery can loose up to 70% of the original capacity.
I had original Motorcraft battery in my Ford Thunderbird for over 14 years but never was run down. Replaced 2 years ago by A C Delco, the largest i could find, very happy with this brand.