Turns out I need a new battery, my local jag specialist supplies & fits Yuasa silver. It's around the same price as a Bosch S5, the Bosch has better specs, but I've heard Yuasa are more reliable for our cars. Anyone have an opinion/recommendation?

 

Over here calcium plate technology batteries are highly recommended since they can take a higher charge without damage as opposed to standard lead acid.

I believe you have more choices over there than over here.

 

Some of the jags of that era (like my STR) have a (not very but partially) smart charge system which is only really suited to lead acid (same kind of battery tech as was OE).

 

https://www.jaguarforums.com/forum/x...6-x350-185125/

Have a look at the above thread.

 

I have quite good experience with my 100 Ah FIAMM, not sure if you can easily get them in the UK. It provides some extra capacity and fits even next to the big LPG tank in my 2003 XJ8. Not much more to say about it except that it starts the car reliably every day at plus and minus degrees, which is about all I expect from it.

 

In Uk I've been happy with tayna.co.uk

 

My original 2005 XJR battery lasted 13 years.

 

 

The Bosch I'm considering is 100ah & 830cca, whereas the Yuasa is 80ah 760cca - as they are the same price the choice would seem like a no brainer, however quality & reliability are more important to me. I stumbled upon a couple of posts where people had failures with Bosch, can't find any such reported issues with Yuasa. Would like to keep my Jag free of any electrical gremlins, but at the same time I'm keen to get maximum bang for my buck. I'll post when I've decided - thanks for the input.

 

I ended up with a Yuasa 5000 019, 100ah & 900cca. The supplier almost sold me a 096 type battery, their listings didn't differentiate between the X350 V6 & V8 engines.
According to my research, V6 is the 096 type whereas the V8's should be fitted with the higher capacity 019 type. Some previous owner had cut corners & fitted a budget 017 battery to my car, it was leaking - no wonder I'd been having issues!

 

For the benefit of other readers who may be seeking a new battery, Box's research, reflected in the thread Jackra_1 linked to in post #4, indicates that the X350 employs higher charging voltages than most autos. The charging system was designed for the original Varta Silver Calcium batteries, which often lasted 10 years or more. Most standard lead acid, gel or AGM batteries, do not deal well with these higher voltages and may age prematurely as a result.

The thread Jackra_1 linked to should be required reading for all X350 owners.

Cheers,

Don

 

Possibly leaking because it could not handle the charging rate over several years?

The previous owner of my 2013 Range Rover Sport had the battery replaced by a dealer and it it is a standard lead acid. So I will check it regularly for leaking.
The charging voltage is a bit higher on the Rover than on my Jag.

 

Regular lead-acid batteries have a gassing voltage of 14.4 V, starting there and higher they will bubble and eventually overflow. Pretty much like a pot with potatoes on the stove.
This is actually intended on some stationary applications in which the liquid inside the battery would otherwise start to separate into different density components. But in these cases they battery cells have to be refilled regularly with destilled water (past times ... I remember my ancient VW Polo). In vehicle applications the battery is typically shaken and stirred enough by the driving motion to keep the acid mixed.

Silver-calcium batteries are supposed to be a superior design especially in terms of lifetime and lower self discharge. But they require a charging voltage of at least 14.4 V or above.Their gassing voltage starts above 14.8 V if I remember correctly.

The X350 charging system is designed for calcium-silver type batteries and provides a voltage of around 14.5 V (that's at least what I get on my cheap crap voltmeter in the ashtray USB-socket), so above the healthy range of a regular lead-acid battery which will slowly but surely be boiled to death.

 

I've often found that the parts database that dealers/specialists use can give incorrect information. It pays to use resources such as this forum, spend a bit of time & do research. A supplier will sometimes just try & sell you whatever they have in stock & need to shift. Never be afraid to second guess them!

 

What country are you in?

my original batt was a Varta silver series, badged as Jag, it lasted over ten years. I got a silver Varta to replace it, there are two recommended, mine is (about) 100AH and very big, same as the original. It is rather heavy.

It's a calcium technology batt.

Manufacturer's ​​short code is H3

 

UK, The battery the supplier tried to sell me was a silver calcium - but physically smaller & lower spec. Same as I had in my old x-type. It may have done the job ok, but for an extra £10 I got the correct higher spec Yuasa. Chances are it will not need changing again for the life of the car.