DIY Underwater Fishing Light


Old 07-12-12, 10:08 PM
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DIY Underwater Fishing Light

I see most 120V fishing lights on the market are using 175W mercury vapor bulb. There are two that use metal halide bulb.....

The MV bulb is exposed to the water and the MH bulb is enclosed in a water tight case on those there a reason for this...I'm planning to build one and wanting to use the MH bulb becasue its brighter.....can I leave it exposed like the Mercury Vapor Bulb design.....thanks for your help.....

BTW, the MH bulb is the "protected" rated one.....thicker glass I assume...
Old 01-13-14, 09:39 PM
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While I have not seen much in the way of "power" fishing lights, I know the 12 volt fluorescents and LED lights seem to be badly overpriced. With that, I am trying HPS, metal halide, and mercury vapor. I think the mercury vapor's spectrum penetrates water better, being all green and blue. The only "protected" lamps I can think of at the moment are the "O" rated lamps with the glass sleve around the arc tube, which is unneccesary underwater.
Old 01-13-14, 11:22 PM
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Welcome to the forums.

The MV bulb is exposed to the water
Not quite sure what you mean by that. The bulb doesn't actually touch water.... does it ?

The metal halide bulb will explode if water hits it. The outer glass envelope runs much hotter due to the metal arc tube.
Old 01-13-14, 11:48 PM
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Yeah I've seen these before.. Their effects are pretty cool. The bare bulb IS actually submerged in water. It uses a socket with a silicone sleeve that seals up against the bulb taper to make the electrical connection waterproof.

Yes a hot bulb will explode on contact with the water, but these are designed to be installed underwater and then turned on. The water acts as a thermal conduction medium, keeping the outer bulb much cooler than if it were in free air.

Honestly I don't see why one type would be encapsulated and the other not, other than differences between manufacturers, probably just with physical protection for the bulb (against impact breakage) in mind. Having a few thousand volts pulsing into the water trying to strike a broken bulb probably isn't a good idea...

Either way works.
Old 01-14-14, 10:21 AM
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Not familiar--but sure sounds like an application begging for low-voltage LED lights. The only limit to the power output of led lamps & arrays is heat sinking--and water submersion would allow several watts without needing a "real" heat sink.
Old 01-15-14, 07:47 AM
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I bet the enclossd lamps are more durable but must be pulled up to be cleaned every couple days, as with LED. An exposed bulb cleans itself from its own heat and can stay down until it goes out.

I am finding my DIY designs safe with all connections exposed, though I denand an isolation ballast. I would not reccomend this project to soneone without proper knowledge of what to check for, and use a test bucket, not the river.

Also, I am not having any luck with pulse start HPS, only probe start MH and HgV. HPS does burn wst if I let it fire dry, tlen put it in.

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