Even good recreational diving lights, typically handheld and meant for open water night dives, rarely last much more than an hour, after which they need the rest of the night to recharge. Alkaline battery torches may last a couple of hours but usually lack the power to light up much of one's surroundings.
Cave dives in Yucatan's shallow underworld easily last 90', with 120' excursions not uncommon, especially when an extra stage tank is carried along. Meaning any light brought into that world of stone and utter darkness, better be extremely durable, robust and powerful. As you can imagine these little underwater stars don't come cheap.
Which is why I originally chose for one of Green Force's relatively affordable modular & expandable solutions: a TriStar Diamond (triple LED head) connected via an umbilical cable to a Flexi II rechargeable battery, thus allowing the heavy battery to be attached to one's harness belt, the light head small enough to be held in one hand together with a reel if necessary.
LEDs don't mind being bumped around a bit and burn seemingly forever, as in more than 9h on one charge for the above system. However, though pleasantly soft for recreational purposes, it didn't quite shine up to its promised minimal 30W output.
Two years later, at boot 2006, I got to talk with Tilly, maker of lights compatible with Green Force's. Being very disappointed by Green Force's misinformation, lack of improved models and having some reservations about their HID lights, Tilly had no trouble convincing me to try out one of his new power lights: a shock resistant TillyTec HID 35, with the halogen equivalent output of about 125W.
Combined with Green Force's Flexi II battery, TillyTec's HID 35 burns brightly at 5500°K for about 90'. Just enough for standard cave dives, but not for extended exploration dives.
So now I'm thinking of getting a TillyTec TT 3 battery pack, a 375€ investment, that should return enough juice for at least 180' per charge, i.e. twice as much as my Flexi II.
This would then free up my Flexi II for a new 321€ TillyTec LED 500. A secondary set-up able to provide an estimated 65W of halogen equivalent output for up to 300' per charge.
Fitted with flood reflectors and diffusers, I'd sure hope these 190W of combined power would provide enough illumination for some decent shootings deep inside the crystal clear water caves around Tulum.
