CASH OR CHARGE?
Most lights you find that are suitable for EDC will run on either conventional alkaline AA or AAA batteries, CR123A lithium batteries or some sort of rechargeable battery pack.
The CR123A lithium batteries were once difficult to find, but they’re available practically everywhere these days. Still, if you use your light regularly, it’s a good idea to invest in rechargeable batteries and a charger. They can save you a considerable amount of cash over time and can ensure that your light is powered up when you need it.
One charger that I’ve found useful is made by Tenergy and sells for $16.95. It recharges one or two RCR123A batteries (the rechargeable versions of CR123A batteries) and includes AC and DC adapters.