I have purchased a (US) 110Volt battery charger to charge the power tool
battery in my country 220V (UK).
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.

Charger details:

Input: 120 V AC ~60Hz 2.0 AMPS (NOM 2.0A) __ Output: 2.8 AMPS DC (NOM 2.8A ---)

My question is: What are the minimum Watts that I require for my Voltage Converter? 45, 100, 200, 300, etc...

I hope that my explanation is a bit clearer this time 'round.

Thanks again

Charger details:

Input: 120 V AC ~60Hz 2.0 AMPS (NOM 2.0A) __ Output: 2.8 AMPS DC (NOM 2.8A ---)

My question is: What are the minimum Watts that I require for my Voltage Converter? 45, 100, 200, 300, etc...

I hope that my explanation is a bit clearer this time 'round.

Thanks again