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Diesel Tech
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Adding a 10,000uf capacitor to the regulator output drastically cut down AC voltage even with a new Mosfet R/R. If you have LED lighting it will greatly extend their life and it should help the stator keeping output smoother.
 

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Discussion Starter #22
Adding a 10,000uf capacitor to the regulator output drastically cut down AC voltage even with a new Mosfet R/R. If you have LED lighting it will greatly extend their life and it should help the stator keeping output smoother.
Did you mean to say the capacitor is on the regulator input ?

Seems like that could make the stator run hotter, but I'm not sure. If the cap is pulling the AC volts down, wouldn't that stress the stator?
 

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Diesel Tech
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No, on the output to smooth voltage to the battery. It took ripple voltage from 150mv to less than 20mv.
 

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NewB to Vulcans
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When you did the ripple measurements did you see any high energy fast transients? I would be more worried about a spike killing the LED's than the ripple you describe.
 

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Diesel Tech
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No. Thats why I use a very large capacitor instead of the tiny little thing commonly used to help control ripple.
 

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NewB to Vulcans
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The little tiny thing is a bypass capacitor intended to reduce spikes, not for ripple control
 

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NewB to Vulcans
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Degreed Electronics Engineer. 40+ years Aviation Electronics design experience.

Spikes and ripple are two very different things.
 

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Diesel Tech
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Depends on your definition of "spike". Saying "I'm an Electronics Engineer" doesn't mean you're right about everything or put an end to discussion.
 

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The blood pressure spike I got from reading this didn't help my heart murmer at all!

I appreciate the info on how to reduce the voltage variance on the R/R output.
 

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Ripple is continuous variation to what ought to be constant DC voltage.
It tends to be repeatable, smooth and (compared to spikes) small in magnitude.
It may or may not be measureable by a handheld AC meter.
Ripple causes damage primarily through heat, as the rising/falling voltage causes continuous current fluctuations through things like batteries and capacitors. They also cause annoying brightness variation in lighting.

Spike, are very sharp peaks in the voltage that may be random or repeatable.
Their magnitude can be anywhere from 1-2 volts to hundreds of volts.
Typically the duration of any one spike is very short, and won't be measurable by handheld meters.
Spikes cause damage primarily through over-voltage of sensitive devices (ECUs, LEDs and other modern electronics).

The line between spikes and ripple can be a bit fuzzy.

Batteries and capacitors can and do smooth out ripple (try running a car without a battery!).
Batteries are too slow to smooth out all ripple, which is where the capacitor can help.
Spikes are way to fast for a battery to smooth out. In fact, large capacitors can be too slow for spikes!
Spikes are best filtered by smaller capacitors.
 
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