The majority of high-powered lights will have an integrated battery. On some models, this can be removed, allowing the battery to be charged apart from the light. This is useful if you have spare batteries, as you can leave one charging while the other is in use.
Most lights will recharge using a mini or micro USB cable, which makes them useful for charging up at work or at home. This will come supplied, with a plug.
Some lights charge with a bespoke cable and socket that will again be supplied with the unit. The light may also have a separate cradle where you can place the light or battery for charging.
High powered lights also take longer to charge fully than commuter lights, and most manufacturers will list how long the lights take to charge with their product details.