Gentlemen, I've wired many a rod n' custom over the years but have never run into this before. I purchased a new 1-wire alternator at last years Back to the 50's and installed it over the winter. I now find that I must run my mouse motor over 2500 rpm before the unit kicks in to charge. Once it starts charging there is no problem, it will charge over the entire rpm range, I just have to remember to rev it up after I start it to get the alternator to kick in. Is this common with 1-wire alts, or is there some other way to get it to charge? I appreciate any and all advice. Thanks,
I thought all 1-wires needed to be “excited” to start charging. No idear what the RPM would be though.
That is how a one wire in a hot rod or custom normally works, Start the car and gun the engine once or twice to get it to energize. I'd say that half the hot rodders that have them have always been in the habit of gunning the engine soon after it started and never knew the difference.
One more bit of relevant info; When I fire up my car, the voltmeter reads about 11.5 volts, indicating the alternator isn't charging the battery yet. After I rev the engine to about 2000 rpm, the exciter takes effect, the alternator starts charging, and the voltmeter jumps to 14 volts, where it stays as long as the engine is running. Hope this helps.
Mine will kind of do that after long cranking. Like when the car has sat for a while and the carbs are dry. I think the battery state of charge get low when cranking for a while ( like until it has oil pressure). Usually by then the carbs are full and the it starts. Takes a few minutes before it starts charging. If you turn on an extra load, such as an electric fan or anything, It may take longer. Turn off all electric loads once it started.
I have one wire alternators on all my cars currently, I have never had to rev them up to excite the alternators, but different brands could require it. If this fixes the issue it was an easy one. My air cooled dune buggy wouldn't charge until I added a light bulb (positive to ignition) and grounded to the alternators field input. The light stays lit until you hit around 1500 RPM, at that point the field turns off the ground (light goes out) and the charging begins (you can actually hear and feel it start to charge). Probably many different variations of the theme out there.
That’s exactly how self-exciting alternators work. note: Trigger rpm’s will very depending on what size pulleys you are using.
So it sounds like a common thing...exactly like "Just Gary" I could wire in the field light I suppose, and see what happens. I even tried looping in the heavy red from the two wire clip onto the main post, even put a ground from the alt case to the car frame, but the issue persists. Back to the shop...
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