Voltage conversion

Please define the need clearly, I do not have the foggiest idea of what your trying to do,

| I have purchased a (US) 110Volt battery charger for my power tool. The | battery is 18V (2.4Amps). I would like to purchase a step-up converter but | do not know the minimum power requirements I need.

Your question is unclear.

What voltages do you want to step up from, and to? Are you trying to step up FROM 110 volts for something else? Or are you trying to step up from the 55 volt work-site voltage used in Britain to 110 volts? Or are you in Japan and need to run this on the local 100 volts?

Or You are in Poland and You need 220 volts. (There is much more countries, don't discriminate them :)) (By the way I'm from beauty Poland)