Stock battery technical specification
 

Greetings all, newbie here, apologies if this is in the wrong place.

I'm looking for the stock/factory fit battery specifications for a 2000 XJ Orvis 4.0 inline-6 auto. When I enter vehicle details on battery websites they all give me slightly different specs. (I'm in the UK.)

I've either got a battery drain somewhere, or else my battery isn't meaty enough, but ever since the weather's been getting cold I've been experiencing VERY sluggish cranking (sometimes non-starting) if I don't use the vehicle for more than a day. Once it's started and warm, it'll start again ten times that day no problem. Use the vehicle every day, and no problem. Charge the battery overnight, and no problem. It's only an issue after it's been sitting for 48 hours or more. I've cleaned the battery terminals and leads and earths, and the alternator is charging at about 14.2v when it's running.

On there at the moment is a 075-spec, 62AH, 620CCA, it's just over a year old, it was listed as the correct spec by a battery dealer but I'm now wondering if that's the correct one. I do have quite a lot of after-market electrical accessories, but everything is run via a small secondary fuse box fed from the ignition live power supply, so in theory none of it should be causing an overnight drain. I'm therefore not sure if I should be investigating down the path of A) a battery drain that becomes more evident in the cold and after a small period of non-use due to cumulative drain, or B) a battery that isn't up to the job in the cold and after a small period of non-use. I don't want to waste money on the one if it's more likely to be the other.

Many thanks in advance for any help.

That battery should be fine.

Clean your battery terminals and see if something is causing a parasitic draw.

same size as my battery, which is more than enough

disconnect battery + terminal and apply a test light or multimeter between battery + terminal and main + cable

test light should not glow at all or current ~30mA or less

It is possible you have a defective cell in your battery which is quite hard to detect, but the battery will lose charge when not connected

it will pass a parasitic drain test (and and sometimes even a load test) when fully charged

You might want to but an off the shelf 51" Bat+ to Starter 4ga or 2ga cable and run a new wire to the starter. If you ,just run it along the old harness and cut the old wire off at the ends, you will save a lot of time. I think the stock measurement is something like 38 inches, but the extra length gives you some latitude on running the wire.