So whats the Defender 200 tdi starter motor CCA rating? Well its all very well chucking 800CCA batterys in Defenders but will the starter motor and standard wiring actually use it or is it wasted?

Doesn't really work like that but I see what you're saying.

A few hundered amps to get these started, more in the cold - it depends what you use your LR for. If you want a reliable cold starter, that can run lots of lights and jump other cars a big battery is king, and lasts longer if looked after.

I have just fitted a 850CCA battery to my 300tdi, I think I took out a 560CCA or something which was 1 month away from being 5 years old, so I think it did pretty well. Anyway, the reasons I went for the bigger battery were:

The cold winter we had last year, a lot of super cold starts, the battery gets a hammering, so a bigger battery means less overall stress on it.

My project Disco battery is almost always pancaked, jumping from a big battery is good, lots of power.

100Ah, I could draw an amp for 100 hours, or any other combination, although I would never want to test this right to the limit it's a good reserve to have. Sidelights for over 200 hours!!

Thanks that was a great reply. I found this also if anyone was interested. DIFFLOCK.com - Battery Guide

Interesting, however a note for anyone reading it regarding the CCA valves given for various engines.

4 cylinder diesel: 700-800CCA - remember that is at -17°C, so at zero it's much less, my vehicle with my old battery even when it was new would not have started my engine below about 10°C but then it was only about 560CCA.

Looks like difflock have copied and pasted an article - after all we're English, but they refer to "gasoline" engines. Also, what a hideous generalisation to lump all 4 cylinder diesels into one group. Different capacities need different requirements. And also, its not just starting (it is mostly, but not all) but also how many electrical accessories etc a vehicle has, to determine its ideal battery capacity.

I imagine the specification required is 560CCA, but many vendors will recommend the 072 type battery which is 600CCA.