So how often do y'all replace your xjr battery. For whatever reason I seem to get about 3 years out of the battery then it simply has trouble starting the car. 1st one came with the car but date wise it was a little over 3 years old when it went. Replaced it with a local business branded battery and got exactly 3 years now for the past few months the battery just seems a bit weak when starting after sitting a bit. I usually put a tender on it every so often as I don't drive it a ton and when I do a fair amount is shorter distances. Put a tender on yesterday and it has not shut off yet so I'm guessing the battery won't go up to the shut off point. Alternator has been rebuilt once and has a rock steady 13.9-14.1. That said I usually go a solid 6 years or so on a battery (even on my motorcycle). Anybody else have a XJ that eats batteries? I'm pretty sure there isn't anything draining it either from doing a few test to check that out.

 

Mine was 6 years old when I replaced it just for good measure.

Batteries are a crap shoot these days. Same brand could die in 3, could last for 7-8.

 

Keeping it on a tender instead of just connecting occasionally will extend the life, and having removable caps which allow topping up with distilled water also helps.

 

Again, I have never had an issue with any other vehicle battery. 1 tender for everything we own and only one car goes in the garage so you need to pick and choose. Never had a car that needed water in the battery. Just one bike. Still looking for others answers on how long their batteries last in their XJR.

 

I had the same problem where the battery tender would not go into float mode. The battery died completely the next day.

Consumer Reports recently said that the average life of a car battery in the US is 3 years.

What brand have you been buying? Walmart Everstart Maxx has a 5 year prorated warranty.

 

The battery in my XK8 was original and when I sold it was still going strong at 9.5 years old.
When not in use my car is constantly on a CTEK and so far I have no electrical gremlins or defective batteries.
Even if you use your car regularly, I would advise at least once per month hooking it up to a smart charger for the weekend.

 

That battery might appear to be going strong, but you can be sure that it has lost most of its capacity due to sulphation. The trouble is, most of the time, a few amp hours is all that is needed to start the car. As long as the car starts, the owner thinks "my battery is fine". Until, one morning, it doesnt start.

My boat batteries get tested regularly by removing a known number of Amp hours, 50 percent of their capacity, at a 20 hour rate, then measuring the resting voltage. Try this on a 9.5 year old battery, and you'll be in for a shock.

 

The beauty about smart chargers is they de sulphate and regenerate the battery. I know exactly how to look after and test batteries correctly, which is why I have not had to replace a battery in over 30 years.

 

Some cars have a small power drain that should be smaller but the owner doesn't notice (who ever bothers to check?). Then the battery is gradually drained. With no maintainer it's just a matter of time till the battery dies sooner than the battery on most other cars (because the other cars don't have that small fault).

On the S-Type we get a few of such per year and after a while if the poster sticks with it find the fault causing the drain.

Oldest S-Type OE battery so far is over 11 years old. I don't see why an XJR would be any different, with the right battery that's not mistreated (such as by a small fault).

A fair number of the drains are due to aftermarket work, badly done.

 

Unless the charger is doing a genuine desulphation cycle, any claims to de-sulphate the battery are probably just marketing spin.

The statement that a 9.5 year old battery is fine is meaningless without a measure of capacity. My assertion would be that, using capacity as a measure, it is highly unlikely that a battery of that age is in a healthy state.

 

All different five year warranty 850-925cca batteries. A prorated warranty is pretty much useless if the battery only last 3 years as in 6 years you've paid them for 1.4x the price of a battery. All of our other cars get treated pretty much the same and have not had an issue. In fact I have a spare battery out of our xk8 parts car that was reading so low I needed to splice two together to get the tender to charge it up after it sat for 2 years or so. It now is a big old jump box.

I remember reading a bunch about others with the XJR having issues in the past with their battery life when compared to the "lesser" kitties like our XK8 that has a 7 year old battery in it that gets charged only if it doesn't move for a month or so.

 

My battery just died at 4 years. It didn't die of natural causes though, it was murdered. My fuel pump failed, and I ran the battery too flat by cranking the engine.

 

The OEM Battery in my XKR is going on 12 years old. The electronics in these cars puts a constant drain on the battery when parked. Sitting even a few days at a time will eventually suphate the battery which adds resistance between the plates. I keep my car plugged in to a Cetek which when not adding a charge pulses the battery helping to remove minor sulfating.


A big key to battery longevity is not letting it go into any deep discharge cycles and keeping the fluid levels up to snuff. NEVER NEVER use tap water which in most areas is loaded with minerals. Spend $2 on distilled water and save early replacement.


Heat is also not a friend of car Batteries. Southern owners will experience shorter battery life than northern owners.


On the 04 XKR the electronics are always running unless you double lock it which puts it in the 'Sleep Mode". I would imagine that the XJR is the same. Be sure to do that if your storing for winter and spend the money on a Cetek Maintainer, they are significantly cheaper than batteries.

 

My current battery is about 6 years old ... I will replace it before the summer. I have been using the Bosch rebranded battery from Pep Boys for about 15 years. It's made by one of the big battery manufacturers -- the same size battery is used by MB, Porsche and BMW.

Bosch just has a $20 rebate and Pep Boys had a $20.00 coupon -- ended up being a bit over $110.00. I currently have 5 cars with the same battery -- I think it now comes with a 3 year replacement warranty.

I have never had to keep my Jaguars on maintainers -- can sit for 3 months and start fine. My two older german cars need to be connected .

 

"I have never had to keep my Jaguars on maintainers -- can sit for 3 months and start fine. My two older german cars need to be connected "

The fact that the car can still start just means that there is enough charge remaining to start the car. The real issue here is sulphation due to leaving the battery in a discharged state.

Let's say that, for the sake of argument, the battery was 50% charged after 3 months. When a battery is left discharged for a long period, the uncharged capacity essentially is lost to sulphation. So your battery would have lost 50% of it's capacity to sulphation after those 3 months. Some of it is not permanent, so the battery would have recovered to some extent. But every time that the battery is not fully charged, some permanent sulphation is occurring.

This is why I say again, the ability to start the car is a poor guide to battery condition. My friend's heart function was down to 30%, but he could do all his daily activities. Did that make him healthy? Of course not.

 

Just replaced the original battery after 8+ years. It was working fine until one cold morning when I got the dreaded 'parkbrake fault' and couldn't release the park brake or move the car. It started fine, everything electrical worked fine...it just didn't have quite enough power to release the park brake. New battery resolved the issue.

The original bettery lasted over 8 years without as much as a burp until it triggered the parkbrake fault. I can't complain at all!