Hi colstonman:

This is going to take someone with more experience than I to answer, but it would help to have some more info:

How many flights/sessions with the NiMh pack charged with the "wall wart" charger?

How did it behave during those sessions, and how long were flight times?

Did the heli do anything different in the last session BEFORE using the Piranah charger?

Have you crashed and how bad and when?

How long did it take to charge the pack on the Piranah?

What exactly are you running for a motor and ESC?

What kind of battery pack?

What kind of battery connectors?

Did the pack OR the ESC get too hot to touch?

Send some of this data along to help analize the situation. Keep in mind that the NiMh packs WILL get warm, but shouln't get so hot that you would burn the back of your hand, for example, unless you have a bad pack or bad charger.

Chat later,

Russ