# How to use a solar panel that has 'watts' to power a battery charger that requires: 3v & 2.8 amps?

I have a battery charger that charges small batteries ( AAA & AA ). It uses an adapter that gives it 3V and 2.8 amps.

I want to remove the adapter and give it solar energy instead. There are cheap solar panels out there (small ones) but based on what I see, solar panels only output "watts" for example "5 watts".

What am I supposed to do with "Watts" if what I need is 3 Volts and 2.8 amps ?

Firstly some theory though. You mention watts, voltage and amperage in your question. These are all different but related. Watts are a measure of power. Voltage and amperage (or better: current) go hand-in hand, like water pressure and flow. Now for your charger you need a supple that provides 3 volts at 2.8 amps. The voltage will be constant, the current (amps) it draws will probably depend on the amount of batteries your charging - 2.8A is the maximum. The relation between watts (P for power), voltage (V) and current (A for amps) is simple: $$P=V \times A$$ So for your battery charger you need to provide at least 3Vx2.8A = 8.4W of power.