Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

30V to more Volts/less current, making homemade lightning

  1. Apr 7, 2004 #1
    If lighting is just a high voltage (not necessarily high current) stream of electrons, would it be possible to make something like that at home? (i.e. 30 volts DC ?)

    how do I convert my 30 Volt battery into something with more voltage and less current?
    Will a transistor help, and what kind? ( i will be using 14, and 30 Volts batteries)
    Thanks, hopefully i get help :wink:
  2. jcsd
  3. Apr 7, 2004 #2


    User Avatar
    Science Advisor

    Peter, first describe what type of lighting device you wish to use. If its a regular incandesant bulb (like a 60W bulb) or fluorescent bulb pair (like in an office) or a low-voltage halogen. Need to figure out the total power requirements.

    Second, power is power regardless of if you have low voltage high current or high voltage low current. Power = voltage * current for electricity like power = torque * rpm for a gearbox. Your car doesn't have any more power in first gear than high gear, but because the tire revs are lower in first gear the torque is much higher for the same power.

    Third, you need a 'power supply' of some kind to step up a DC voltage from a battery. Basically you take the DC and with a transistor switching on/off rapidly turn it into AC, then run it into a coil of wire to convert it to magnetic energy, and then convert that to a higher voltage. Easy way to get this all done would be to buy an off the shelf 12V DC to 110V AC inverter at a store designed for use in a car or RV. A car's alternator runs at 14V while the engine is on, so a 14V battery should be ok.

    Fourth, you may want to re-think the design objectives. You want light and without any extra parts a 55W automotive headlight or those off-road lights (spot and wide-angle) will work fine on a 14V battery. Wire two matched lights in series, and now they can run off the 30V without any extra parts, the extra voltage should make them just slightly brighter and shouldn't shorten the life too much.

    Lastly, how much battery you got? You can look at the Ah rating (ampere-hour rating) to get an idea how much power the battery can deliver and for how long it can deliver it. For example, a 14V battery with a 3Ah rating could run a single 55W headlight for about an hour when the battery is brand new. A pair of headlights would likely last close to 15 minutes, note how the increased current shortens the time considerably as the battery can only deliver so much power and its life drops dramatically as you try to draw large amounts of power from it.

  4. Apr 7, 2004 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member


    I think he's talking about lightning, not lighting.

    You'll need to use a switch-mode boost converter like the one that Cliff mentioned to make high voltages from low ones.

    - Warren
  5. Apr 7, 2004 #4
    yes, sorry, stupid mistake
  6. Apr 7, 2004 #5


    User Avatar
    Science Advisor

    LOL, thanks Warren, one letter makes a big difference, guess I read the message and not the subject!

    Peter, LOTS of voltage. Another option might be a static generator like the one with a rubber belt that rubs against different materials. Or a telsa coil. I did a quick search on google and this was the second link:

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook