How to cycle or revive your SL50 or TL50 dive light's battery

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Q: Gentlemen, I bought a demo unit from you in late June of 2007 ... have never used it underwater ( except in the pool ). I charged it and discharged it ea 6 months, and got about 45 min burn time the first couple of times , but now only 16 min, and it flickers from full charge till 15 -16 min ...I think it has a 50 watt bulb . Is there a way to bring the battery back up to speed ?

A: Try to cycle it (charge and discharge it) several times and the battery pack should slowly revive itself. Give that a shot and see what happens. To discharge it on land you can remove the light cover and just let it run, just don't look at it and make sure the light is not in contact with anything because it does get hot.

Q: Right ! I'm having good luck with the cycling ... got almost an hour now ...I would have bet some non essential body parts that this would'nt have worked... these nickle/metal hydride batteries must be similar to Nickel Cadimiums ...I know they develop a memory if you charge them too long, or too often, or too much. Tell me how I correctly charge these ?Thanks for the time and info ...

A: Basically what you would have to do is keep the charger on there for about an hour after the light turns green. Red means it's on quick charge and green means trickle charge. If you keep it on green for too long it may damage the battery but a typical charge is between 2.5-4 hours.

NiMH is still different from NiCads in the sense that you cannot really revive a NiCad battery the way you would with a NiMH Battery. Always store it on a full charge and charge it fully before you dive. If you're using the lights with a couple months' gap in between you should cycle it once or twice before jumping into the water just in case.