Generator for Trike lights using 2.5 hp HF engine

Discussion in 'Electrical' started by fleebell, Jul 30, 2011.

  1. fleebell

    fleebell Member

    I've decided I want to put a full 12v lighting system with turn signals, brake lights etc back on the trike and was wondering how I could do it without having to take a battery pack off and charge it all the time. The last time I had a full set of lights on it was when I was using an electric motor system and I could just tap off from the batteries for that.

    So far the only thing I can think of is either mount some solar panel somewhere on the trike or add a generator somehow to keep the battery for the lights charged.

    The solar panel is pretty much a no-go from the beginning due to cost so that left me with the generator option. There isn't any simple way I could see to get electricity at the voltage and current level needed from adding an extra coil near the flywheel and it's magneto magnet. There is not enough space to mount one inside the engine cover I could see.

    That left me with an external generator of some sort the engine could turn. I think the simplest way would be to drive a small motor with a hard rubber wheel mounted to it from the outside of the clutch bell. That thing gets a bit hot so it would have to be some sort of high temp rubber.

    So what I'm going to try out is a simple hinged motor mount that will bolt onto the side of the engine that would allow the rubber wheel to come in contact with the clutch bell. A small spring on the hinge will keep it in contact.

    I have a box full of small dc motors to work from. I think I'm going to try a motor from one of the small 12v kiddie cars first. They are designed to turn at high speed and have heavy wiring compared to most motors in that size. If I use a rubber wheel 1/3 the size of the clutch bell the motor will turn at a max of about 13000 rpm at the trikes full speed. It should be about 6-7000 at my normal riding speeds. Hopefully that should be plenty of output to keep a small 4.5 amp 12v lead acid battery charged as I won't need but a couple of amps. I might have to use a voltage regulator to keep from overcharging it.

    Here is an overlaid drawing of the engine. It shows where the motor would be mounted and how.


  2. professor

    professor Active Member

    You will need a regulator if you want to avoid cooking the battery, look for a snomobile one.
    I bought a 2 wire square one a couple of years ago and finally figured out how to wire it, - power in to yellow wire - power out to lights via the other wire.
    I an using a 250w scooter motor (unregulated and no battery) as a dynamo, driven about 1/3 speed off the Hf 79.
    Maybe you can cut a pulley down and place it behind the clutch. Or a #25 chain. McMaster carr has sprockets and pulleys and will sell to you if you use a charge card.
  3. fleebell

    fleebell Member

    I had a feeling I probably would need a regulator. I'm still going to try one of the small motors by itself first though. I have a bunch of them to play with.

    I could drive it off the jack shaft with a belt or chain. That would be 1/4 the engine speed and give me a range of pulley options. I want to try it driving it from the clutch first though as most of these little motors are designed for high rpm speed and they don't weigh much or take up much room either. I always like to keep things simple as possible at first on these type of projects. If I have to get more complicated with the setup I will but this should work with a regulator like you suggested. A neighbor just gave me an old moped this afternoon that has some kind of mechanical engine problem. I will try using the regulator off that. It should work for this just fine.

  4. professor

    professor Active Member

    Speaking of mopeds, many parts are useful to us. My current project is using the front end and wheels off one.
  5. fleebell

    fleebell Member

    The first attempt at the little generator mount has been made and installed.

    I found the little motor from the kiddie car would supply about 3-4 amps at battery voltage with the trike full speed and about 1.5 amps at my normal riding speed so it should work fine. The motor would fully light up a regular car halogen type fog light so if I decide I need a really bright headlight the little motor it will supply it. Open voltage on the motor (no load) with the trike engine running full speed was about 32-34 volts - definitely needs a regulator.

    The first picture below shows the motor in the operating position where the drive wheel is against the clutch bell. The second picture shows it lifted up and a disengaged position so the mount shows up a little better. I'm sorry the pictures are not clearer but the little cheap camera I have doesn't do close-ups very well.

    The motor mount is a piece of heavy sheet metal with a hinge welded on to it in the middle. It's mounted on the engine side mounting bolt holes and simply clamps around the little motor. The spring holds the wheel down against the clutch bell. It's just got a rubber wheel from toy car on it at the moment but I plan to make an aluminum wheel that uses a really thick o-ring as a tire. (I have a bunch of those o-rings I got from somewhere when recycling stuff......)

    Large pic link 1

    Large pic link 2