Geoff,
 That battery pack is a "C" cell pack and is going to add a lot of extra weight to the plane.

Byris,
Yes, you can charge a higher capacity battery with a wall wart charger. Howver, it's going to take longer to charge than the 10 hours you can charge your smaller battery in. It could take a couple days to fully charge a battery that big with that charger. I usually advise people to pick up a good charger when they start moving up to bigger batteries than what came with the plane. In this day and age it's a good bet you're going to need a good charger sooner than later. With all the changes in batteries it's well worth the money. Even if you never move past the Ni-mhs in planes it's still worth the money as you can use the charge-discharges to condition new batteries, as well as using discharge to monitor battery packs to find out when they start going bad. With a better charger you'll be able to go back to charging the bigger battery in 10 hours.

Byris,
I sent you a PM a few days ago, but it's showing that you didn't read it. Quick question. I noticed you are with the Imperial club there in Lakeland. Will you be working Florida Jets or Top Gun with the club???

Ken