Perhaps my iPhone 3G's Exchange is draining the battery?

I’m wondering if one of the primary reasons that my iPhone 3G is draining it’s battery at a shocking rate whenever it’s unplugged is due to the Exchange integration?

I was delighted when I was able to configure my device with my calendar, contacts and whatnot. It just sucked down all my data and whenever I add a contact or calendar entry on my desktop — woosh — it appears nigh-on immediately on my iPhone.

But that must account for some kind of overhead, right? It’s apparently ‘pushing’ to the device. I’m thinking of changing it to ‘pull’ (although I’m not quite clear on how I actually ‘pull’ data down. Maybe a ‘sync’ button appears?).

We shall see. Has anyone else been using Exchange on their iPhone whilst the battery drains before their eyes?