Paul was popular at the Transform Weekend near Ollerton when he turned up with this drill battery. Turns out that these days they also have USB ports so they can be used to charge phones and tablets. It's a big one - 5.2Ah. Amphours is a measure of charge stored, Current is defined as the rate of flow of charge. So I=dQ/dt. Hence charge transferred dQ= Idt. I is measured in Amps. dt can be measured in many different units. Here they have chosen hours. I normally use seconds because the unit "Ampseconds" is the same as Coulombs. Since 1 hour = 3600 seconds, 5.2 Ah = 18700 Coulombs. Anything that can deliver 5.2 Amps for 1 hour is amazing!
