12 volt question

Discussion in 'The Projects Forum' started by iowabucks, Mar 10, 2009.

  1. iowabucks

    Thread Starter New Member

    Mar 10, 2009
    Hello everyone, New member here. My name is Jerry. I have a project i found on a fishing website that i am in the process of making right now. I have always wanted to do some night fishing and had read a couple articles on how great the crappie fishing can be at night with an underwater light source. I ran across a thread that showed how to build a green fluorescent underwater light that runs off 12 volts. A commercial version of this is made and called the Green Monster. Costs about $185. A parts list and explanation showed how easy it could be built for about $60.
    It is built from 3" PVC tubing. They used a fluorscent bulb cover for the tubing, but i went with schedule 40 clear PVC for added protection. It takes an industrial green F20T 12/G green fluoresent bulb, and an 18 watt 12 volt ballast. I have links below for the bulb and ballast.

    My question is when i wire the bulb to the 12 volt ballast, what gauge wire should i be using? I don't want anymore resistance than i need.

    Put a couple battery clamps on the end of the length of wire running from the ballast to the battery, seal it all up with %100 silicone and i should be in buisness. Is there a certain type or gauge wire i should be using to go from the battery to the ballast too, seeing that i'm only running 12 volts to the ballast?


    These are pictures from the thread i was reading. I'm in the middle of it right now but haven't done any wiring yet. I'm building two, just to be sure i have enough light.

    Any other tip?
  2. thingmaker3

    Retired Moderator

    May 16, 2005
    Mmmmm.... Crappie!!!:D I get to come along if I help design the thing, right?

    The 20 Amp bulb will only draw about 1.7 Amps. Double that for two in parallel.

    14 gauge will be plenty big enough. You could get away with 22 gauge, but why scrimp?

    You did notice the minimum order on those tubes was 6, yes?

    And shouldn't you be using an IBL-151 ballast with a 20Watt tube instead of the IBL-153? Or a 32 Watt tube with the IBL-153?
  3. bertus


    Apr 5, 2008

    I think you mean a 20 Watt bulb.

  4. iowabucks

    Thread Starter New Member

    Mar 10, 2009
    No. i didn't see that. Already got the bulbs from them. Just has a $25 minimum order.

    Yes i did order the IBL-151. They had both ballasts on the same page, but i ordered the 151.

    Thanks for the input. I was clueless on the size wire to use. I can solder, but don't know much else about electronics.

    I found a roll of 18 gauge wire. Will that hurt the performance of the light or the battery using this size compared to 14 gauge? Should be about 15 feet long. Will it help to cut it down to 10 feet?
    Last edited: Mar 11, 2009
  5. thatoneguy


    Feb 19, 2009
    Doubled length of wire to account for + and -

    30 ft, 18 Ga stranded, 2A: 0.2 Ω, Lost voltage 0.4V, Lost power 775 mW

    30 ft, 14 Ga stranded, 2A: 0.08Ω, Lost voltage 0.15V, Lost power 300mW

    20 ft, 18 Ga Stranded, 2A: 0.13Ω, Lost voltage 0.3V, Lost Power 500 mW

    20 ft, 14 Ga Stranded, 2A: 0.05Ω, Lost voltage 0.1V, Lost power 200 mW

    "Worse Case" Difference is 0.3V Drop. Shouldn't be enough to drastically effect the output of the light between 13.5 and 13.8V.
  6. thingmaker3

    Retired Moderator

    May 16, 2005
    Um... the cat walked across my keyboard. Yea.:cool: