well cold weather has killed the battery in the other car (forester). it was 7 yrs old.

Now in finding a replacement i found a 560cca 13 plate battery for a good deal from my local mechanic.
Stock was 9 plate 440cca battery.

Would replacing it with such a large cca battery cause any problems such as draining too much from alternator or would there only be benefits with cold starting from all the extra cca and 4 extra plates for charging.

7 years is excellent life.

Bigger battery
Benefits: none that I can think of. 440 cca is enough for a V8
Downside: carrying around extra weight. It won't hurt the charging system.

We're going with smaller batteries here...less weight, better fuel ecomony over the long run.

yeah same in the datsun but for the family car, just need it to start first time every time for the mrs

I know what you mean. Mrs ddgonzal has a Forester too (blue 2.5). It needs to start every time.

My best advice is buy a quality brand battery, it should last another 5-7 years without any problems. Subaru here has reasonable parts prices, I wonder if they sell batteries?

yeah us suby is way cheaper, an afm for my model in aus is $750... us shipped to my door is $280 aus with current exchange rate and 7 day delivery time!

They sell batteries but too expensive from them for stock one.