Retrofitting a Nemo 8C Dive Light With a LED Spot




Introduction: Retrofitting a Nemo 8C Dive Light With a LED Spot

About: I am creating interactive installations and performances. Inviting the spectator to participate in various ways I use any media possible to bring "the idea" to life. Electronics, computers, wood, rope, wat...

A friend of mine have several old Nemo 8C dive lights. It is a sturdy lamp, favored by many divers around the world.

But as with anything having a classic halogen light bulb inside, the power use is high, and the light output is only great when you have absolutely fresh batteries.

As a test, we have retrofitted the Nemo dive light with a 12 V 7W LED spot.

As you see in the video, the light output is huge, and our tests so far show impressive battery life.

Step 1: Find a 12 V LED Spot and Make Room for It

Find a good quality 12 V LED spot.

I used a 7 W 12 V LED spot of the type to replace halogen light installations from Aura Light.
I would just go with whatever quality brand LED spot you have available locally.

7 W of LED light is roughly equivalent to 50 W of halogen light. That's a lot of light!

The ones with a GU 5.3 socket are great, because the GU 5.3 is basically two straight pins, that are easy to solder wire onto.

  • Bend up the metal strip connectors for the old bulb
  • Using a drill or a clipper, cut away the plastic of the old socket, and make room for the back of the LED
    • Make sure to make the hole deep enough to have the spot fit under the glass of the lamp
    • Take care to still leave the battery shoes intact, since we want to reuse all that.
  • Cut the metal strips from the old bulb away

Step 2: Solder Wires to the LED Spot and Mount It

  • Solder two pieces of wire to the LED spot.
    • The GU5.3 has nice pins that is very easy to solder wires onto.
    • Polarity is no problem - The LED spot will have rectifying diodes inside fixing that.

  • Solder the other end of the wires to the metal strips.
    • If you are having trouble getting the solder to stick, file a little bit on the strips to disturb the surface

  • Mount the LED spot in the hole you made, and make sure it is embedded deep enough to fit behind the front glass.

  • Once you are sure the assembly works, secure the LED spot with some hot glue.

Step 3: Put It Together. Test It!

Assemble the lamp as you always do.

Make sure the hot glue have not interfered with the batteries ability to touch the battery shoes.


Obviously a dive light is a safety item. You don't want it to burn out on you in the middle of the dark water.

I ran this lamp for 4 hours on the table, to make sure, that it would be stable.

A powerful LED spot like this 7W spot will produce quite a bit of heat. No where near as much as an equivalent halogen bulb would produce, but after the 4 hours the temperature inside where up in the 50-60 degrees Celcius area.
Using the light under water will provide much better cooling.

So, make sure your light works on the table before taking it out to sea. There is a lot of quality difference between LED spots, and if you have chosen a cheap crappy one, there is a good chance, that it will not survive the temperature inside the lamp house.

Battery time

The batteries I used for testing was not new, and had a combined output of 9.2 V when I started the test.

After 4.5 hours the voltage had dropped to 6.9

New batteries would have given out 12 V

Still, after the 4 hours and with only 6.9 V supply I had massive output of light.

Further studies

I have not yet tried out this hack in the water on a dive, but I am quite confident, that it would do the job at least as well as before. The light output will be similar or even more powerful - But the battery life will be much much longer.

I will post an update once this light have seen some sea trials.

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    2 Discussions


    Question 10 months ago

    Hello, have you tried it under water?, you are confident that o-ring will be leakproff?


    Answer 10 months ago

    The dive light he is using is a Nemo 8C. It’s made to be used underwater and his retrofit didn’t alter the seal of the light in any way. This instructable is why I bought the light. I hope this helps.