There are a few things to consider when purchasing a 500-lumen dive light. Look for products with a solid construction, dependable long-life battery, and suitable depth rating, and keep your budget in mind.
Construction
Anodized aluminum makes the best housing for a dive light. The material will not corrode and is strong enough to handle bumps, drops, and various underwater environments.
Battery
You want at least six hours of battery life in a 500-lumen dive light. Dive lights with a higher lumen capacity require more battery power to account for the extra brightness, but because 500 lumens is far from the brightest option out there, it’s relatively easy to find a lights that use high-capacity batteries.
Depth Rating
A good 500-lumen dive light can withstand submersion of up to 100 meters. Novice divers tend to overlook depth ratings, as they don’t often go deeper than 100 meters. However, there is always the possibility of dropping your dive light while under water.
Illumination
A 500 lumen dive light should give you a beam distance of at least 250 meters. The best bulb to use would be the CREE X-ML. The dive light should concentrate at least 75% of the light in the center of the beam, and the remaining 25% on the outside of the beam to widen the field of illumination.
Pricing and Recommendations
500-lumen dive lights rarely go above the $100 mark. It is somewhat cheaper to get the rechargeable products over the long run, but non-rechargeable 500-lumen dive lights tend to use standard batteries, so the replacement cost is low.
Products from Dorcy and Kraken meet the above specifications. If you buy a Dorcy dive light, you can expect extra features like an adjustable strap and extra batteries. On the other hand, most Kraken products come with battery-level indication and three light modes; white, strobe and SOS.