I am a new owner of a 2007 Jaguar XK convertible. After sitting in the garage for a week it did not start. I bought a trickle charger and that has helped. The battery is almost 5 years old. Any suggestions on what type of battery to get.
Thanks,
Elliot

 

This battery has been great for me. Not sure if there is a Batteries Plus near you.
https://www.batteriesplus.com/batter...00cca/sli49agm

 

Type 49 and a Ctek 4.3 maintainer.

 

 

I've use Interstate in my XK.
When it was time to upgrade my XKR I found some basic analysis data online that steered me into trying the Bosch.

 

90% of all batteries sold in the USA are manufactured by Johnson Controls. The same battery is encased in different jackets for different retailers with the only difference being the logos and such markings.

 

Exactly- the only difference other than the label is the warranty.
Buy the one with the longest warranty- from a place that is going to be around in 4 years from now.

 

^^ True. The Bosch Advanced AGM from pep boys is 4 years.

 

Last January, I replaced the original 6-year old AGM primary battery (it also has a secondary stop-start battery) in my 2013 XJ with the Bosch AGM from Pep Boys for $175.99 plus tax. They did an excellent job and I've had no problems.

I would not use an AGM battery in my XKR since it came from the factory with a conventional, flooded "wet cell" battery since (1) the charging profiles are different for AGM and flooded batteries, and (2) AGM is not worth the additional cost. Sure, many Forum members have replaced their OEM flooded batteries in their X150 XK/XKRs with no apparent problems, but that's not what the factory recommends. I'll stick with the factory recommendation and replace my XKR battery with the same type.

 

As I (not very fully) understand it, AGM needs in effect more volts for longer so won't be charged properly with some/all of the cars (4.2 etc) but if you happen to use a ctek then that should do it.

I've stuck with an ordinary wet lead acid battery for my car and don't even use a ctek as the car seems to keep the battery charged OK - but I use my car quite a bit.

 

This is a common misconception, and thank you for your candor.

If anything, they are susceptible to overcharging as they charge quickly. However, its unlikely in an XK because they are not driven that much.
In reality the quick charging property helps the typical Jaguar not driven 2 hours a day on the motorway.
Regardless, if you overcharge an AGM, you merely reduce its life, but you start with twice the life and twice the warranty.

The biggest advantage- regardless of cost, is that it will not rust your battery compartment as a regular battery will do with near certainty over time.
Which in a XK sits in a critical area.

For further reading:
"AGM batteries have several advantages over both gelled and flooded, at about the same cost as gelled:Since all the electrolyte (acid) is contained in the glass mats, they cannot spill, even if broken. This also means that since they are non-hazardous, the shipping costs are lower. In addition, since there is no liquid to freeze and expand, they are practically immune from freezing damage.

Nearly all AGM batteries are "recombinant" - what that means is that the Oxygen and Hydrogen recombine INSIDE the battery. These use gas phase transfer of oxygen to the negative plates to recombine them back into water while charging and prevent the loss of water through electrolysis. The recombining is typically 99+% efficient, so almost no water is lost.

The charging voltages are the same as for any standard battery - no need for any special adjustments or problems with incompatible chargers or charge controls. And, since the internal resistance is extremely low, there is almost no heating of the battery even under heavy charge and discharge currents. The Concorde (and most AGM) batteries have no charge or discharge current limits.

AGM's have a very low self-discharge - from 1% to 3% per month is usual. This means that they can sit in storage for much longer periods without charging than standard batteries. The Concorde batteries can be almost fully recharged (95% or better) even after 30 days of being totally discharged.

AGM's do not have any liquid to spill, and even under severe overcharge conditions hydrogen emission is far below the 4% max specified for aircraft and enclosed spaces. The plates in AGM's are tightly packed and rigidly mounted, and will withstand shock and vibration better than any standard battery.

Even with all the advantages listed above, there is still a place for the standard flooded deep cycle battery. AGM's will cost about 1.5 to 2 times as much as flooded batteries of the same capacity. In many installations, where the batteries are set in an area where you don't have to worry about fumes or leakage, a standard or industrial deep cycle is a better economic choice. AGM batteries main advantages are no maintenance, completely sealed against fumes, Hydrogen, or leakage, non-spilling even if they are broken, and can survive most freezes. Not everyone needs these features."

 

Hadn't bothered to investigate the advantages. Thanks for posting.

 

Maybe not. Why take any chances? If you have an AGM battery in your XK/XKR, make sure it's vented. Otherwise, AGM could give you an unexpected bang for your buck!

An AGM battery installed in an X150 is prone to being overcharged because the OEM charging system was not designed for AGM. The battery compartment is small, and if your AGM battery is not vented to the outside, overcharging will cause hydrogen gas to be released with potentially disastrous consequences. Hydrogen is explosive and corrosive.

 

Stuart the XK is vented- it has to be because it uses the most volatile battery- a lead acid.

All batteries are prone to being Undercharged in an XK, even XJ.
This is why they all have to be supplement charged with a ctek.

(p.s. there is actually no difference between the charge rate of an AGM and lead acid battery- there is a negligible difference in the float rate, {float rate being if you are going to leave it plugged to a charger for a long time})

 

Q&C, you misunderstood what I wrote. Of course, every X150 battery compartment is vented. But not every AGM battery in an X150 has the vent tube attached to the outside. My point was that you stated, in part: " ... AGM batteries ... are ... completely sealed against fumes ... " That's not accurate. If overcharged, AGM batteries can emit hydrogen. Be safe and vent your AGM battery to the outside.