Hi Ruiz-Thank you for the reply. The battery I used is Nickel metal, not NiCad. Wren says to use NiCad-and not to use Nickel metal. The engine wont settle into an idle of 45K, it only gets to 22K. The parameters are all where Wren says they should be. I think the reason Wren says not to use nickel metal is the amperage isnt as great as say a NiCad or Lipo type. I have emailed Sara at Wren, but being Sunday I havnt received a reply yet.