Mark, Bill or whoever is running one of the small dynamo power generators, I have a few questions. Mark L I looked over your electrical pages on your website. Just curious if your system is the same as your drawing? In your drawing I did not see your dynamo powering the system. What I am after is some help for one of my neighbors who has a VP1. He installed a Compufire system and now has extra power needs. Steve at Great Plains says that the Compufire uses 6 amps when flying. What my neighbor is thinking about doing is making a wind generator using one of these little dynamos. What is the simplest and cheapest way to wire up this dynamo to his little battery,VP1s do not have a lot of ability to carry heavy things like big batteries or ?. Anyone have a simple drawing of parts and hook up for him? We are thinking about trying one of the fan motors mentioned below as a power source. Who woulda thunkit ? Thanks Larry H.
Below is a statement from a fellow on another group that I thought some of you might be interested in. The part concerning creating too much power by a dynamo or other unregulated generators or alternators using a zener diode. Another possibility for a wind generator would be an electric radiator fan from a small car. Usually the fan is 8", 10" or so in diameter and can probably be purchased inexpensively from a junkyard. It needs a diode in series with it so it charges the battery as a wind generator, otherwise it will be a fan and use current instead of producing it. It would be best to experiment with this setup first. Mount it on a pole sticking outside a car away from its slipstream and drive it at VP cruising speed. You should have the battery connected to it with a voltmeter across it and also some sort of dummy load that draws about the same amount of current as the compufire does. If you see the voltage stays at around 13.8 or greater at cruise speed with the dummy load powered up, the "wind generator" is capable of doing the job. If not, you might try a bigger radiator fan and motor. If the voltage is too high, over about 14.5V, a possibility of overcharging the battery exists. In that case, a way to "waste" the excess power has to be devised. This can be done by connecting a 14V zener diode across the battery. This device will begin conducting and using power when the voltage goes above 14V, otherwise, it does nothing when system voltage is below 14V. Be sure the zener is capable of dissipating the excess power created by the wind generator else it will overheat and burn itself up, leaving the voltage unregulated and too high. The final VP installation should of course be switched off from the battery when not in use and the VP instrument panel should also be equipped with a voltmeter, ammeter or both to monitor charging system performance in flight. If something goes wrong with the system, it can be switched out of the circuit. The battery installed should be large enough to drive the compufire long enough to allow a safe semi emergency landing in case of charging system failure.
