The battery pack needs to have a standard servo plug on the balance lead. A lot of A123 packs are sold that way.

You can usea Gen 1 charger if you have his adapter harness, oryou can make your own. If you have a Gen 2 chargerthenyou need an adapter with a balance plug on one end and a standard servo plug on the other.

Once you have the adapter harness it's very easy to convertyourplanes from nicads to A123's. There are no special switches or anything else to buy.

Joe