John, Set it for the biggest peak, 17.5V looks to be the one. Corby ____________________________________________________________ Digital Photography - Click Now. http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTDvmQS0Oh2LuVYMuNJq4DRE9ltVihQk6NZdYzCLTetZVGTQjA4zHi/