Re: 1970 1150 rectifier or "radio shack full wave"??
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Well I think I'm going to go with the full wave 25 amp and make an aluminum plate for it and find an old heat sink from a computer for it. What kind of voltage are you guys seeing out of these?? I would rather not go over 14 to 15 volts to keep from shortening the battery life. I know kind of how these work and I guess you can't use a regular voltage regulator as you have to change from A/C to D/C voltage...is this true? Are there different types of "radio shack" models that will give me different voltages to the battery?? How will I adjust this or is that possible?? Also, sorry for all the ques...I'm going to put together and install with pics and results of what I get at varying rpm's. Now the other question, where do I install my tach wire on this?? can it go on either of the A/C posts coming from the stator?? Thanks again for you help.
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The difference between rectifier junction voltage drops, like 2-3 volts for selenium, and 0.5 - 0.8 volts for silicon is insignificant compared to the no-load supply of 70 volts or more available from the stator. The current is controlled by the stator, as it can only put out so much, and the voltage will drop to limit that amount. It's in the 12 - 15 amp range. The voltage is limited by the battery. It uses the excess current to hydrolyze water into hydrogen and oxygen. That's why batteries need ventilation, and also why they use water. Eventually this destroys the battery, but it takes a couple of years.
If you install a bridge rectifier, the stator wires go to the terminals marked either AC or ~, the - terminal is grounded, and the + terminal goes to battery. The tach hooks to either stator wire.
You can retrofit a voltage regulator from a later Merc motor, either a 16 amp, or one of the 2 in a 40 amp dual coil system. Yellow goes to stator, red goes to battery, and grey goes to tach. It needs reasonable heat sinking, so bolt it to something aluminum, not plastic. That has a cost of a little over $100, but takes a little load off the stator and lengthens battery life. Use an aftermarket one. The Merc regulators are notoriously weak.
hope it helps
John