Whilst the capacity and CCA of a battery might be significant when new, I believe quality plays a much bigger part as soon as the battery has aged a little.
Those two ratings don't tell the whole story either. They represent the discharge at a 20 hour rate (way slower than when it is discharged when trying to start the car), and the maximum current output at a temperature lower than we are likely to see in the UK.
Batteries are seldom discharged to anything like their true capacity so the fact is that you could probably get away with a 15AH battery as long the it could deliver the required cranking current - provided you don't use too many electrical items when the engine is stopped.
A more hefty battery might last a little longer in a given application, but then again quality is probably the biggest factor.
I recently changed the battery in my Westfield for one physically identical to the one I've had on it for 5 years - but new, and it cranks much easier than the old battery ever did even when new. I always suspected the starter motor was not man enough as even when the old battery was new I always had trouble restarting after refuelling, but with the new battery it is perfectly happy. The funny thing is that both the CCA and the AH ratings of the new battery are lower then the old one yet in real world usage it's a better battery. They are both Halfrauds own brand too, although probably from different suppliers.
Kevin
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Topic: Quick battery question (Read 801 times)