Dive Lights - The Basics

Sep 26, 2009

 Dive Lights   

To provide illumination at night, you need a dive light. It is your primary light source on a night dive. During the day you may use a light to look into cracks and crevices. Dive lights are also used for exploring the insides of wrecks, underwater caverns and caves.
Also known as : underwater flashlight, dive torch, lamp, canister, light, HID, tungsten light, LED light.


There are two basic styles of dive lights, with different options in rechargeable or disposable batteries, and the type of bulb it uses.

  • Flashlights – These range from small, compact lights used during the day or as backups for night, wreck and cave diving, to large lantern-style lights that are primary light sources when diving in the dark.
  • Canister lights – Used primarily by wreck and cave divers, canister lights supply a compact light via wire with power from a battery in a canister carried on your waist. Canister lights are usually much brighter (though this is changing as lighting technology advances make smaller lights more powerful), so this makes carrying their larger batteries more convenient.

Required features
  • Water tight and pressure proof – Any dive light will be designed to exclude water and resist pressure to its rated depth. Avoid “waterproof” lights not intended for diving because they may collapse and fail due to pressure. 
  • Durable and reliable – The dive environment is not gentle on equipment. Dive lights need to be strong enough to withstand reasonable wear. 

Desirable features

  • Rechargeable batteries – Unless you use your light very rarely, rechargeable batteries are the way to go in larger lights. They pay for themselves, and they reduce the number of batteries going into landfills. Many lights perform better with NiMH rechargeable than with disposables, so you not only save money and help the environment, you also get better performance. 

Optional features

  • Size – Although powerful lights are getting smaller, there’s a relationship between size and power/brightness. Small lights are your best choice for day uses and as backups. Large lights are your best choice for night diving, wrecks or caves. These are sometimes called primary lights because they’re your primary light source. 
  • Tungsten, halogen, HID, LED – Bulb types are changing rapidly, allowing lights to create more light with less power. Tungsten and halogen bulbed lights cost less, but are not as bright and use more batteries. HIDs and LEDs are the cutting edge – a 10 watt HID puts out the same light as a 50 watt halogen yet requires only 20% of the power. LEDs are even more efficient and much more durable. 

  • Disposable/rechargeable – The latest lights use AAs and other common sizes and accept both rechargeable or disposable batteries. This means that even if you use your light only infrequently, you can use rechargeables if you keep sets around for other uses. If you want to keep your light ready to go and open it only once a year, high quality disposable alkalines are fine. 



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