There are three major types of batteries which cover the vast majority of dive lights. In this post, we'll provide a background on all three types, cover the advantages and disadvantages of each, and provide some basic recommendations for choosiing batteries.
Alkaline battery dive lights take common household batteries (like AA or C). These batteries are available everywhere and are even easy to find even in remote dive locations. They are also inexpensive. Those are their two giant advantages. Disadvantages include their performance. They don't have the battery life or power production that Lithium ion batteries do.
Lithium ion batteries (CR123 photo batteries) delivery incredible power for their size. This leads to greater battery life, greater brightness or both. The power consumption curve for lithium ion batteries is also pretty flat, meaning they maintain a more constant level of power (i.e., brightness) over the life of the battery, as opposed to alkaline batteries which have a steeper power reduction over time.
Lithium ion batteries so have some drawbacks. They can be hard to find, especially in remote locations so its always wise to back a spare set of batteries. From an environmental perspective, CR123 batteries are not rechargeable and Lithium is considered environmentally unfriendly by some. These batteries can be recycled however, which is what we advise. Lithium ion batteries also fall under some air travel and shipping guidelines that warrant attention but generally do not impact your ability to travel with them.
have the advantages of being environmentally friendly and very low operating costs since they don't need to be replaced after each use. Rechargeable batteries require both the time to recharge between dives and an appropriate power source, and generally require charging right before use because they don't hold a charge well over time.
Divers who dive frequently typically choose rechargeable batteries for their primary dive light. Recreational divers often choose Alkaline or CR123 batteries for their primary. Alkaline and CR123 lights are also ideal for backup lights.
(Image Source: Wikimedia Commons)