B&S 21Hp Battery Charging Issue

StarTech

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To be honest I have never measured the voltage there, key off because there is no point in doing it
Just battery voltage engine off and battery voltage engine on
I also check for AC at the battery engine running which shows the stator diode has failed open circuit.
Sorry if the diode should fail as open circuit there will be no voltage either AC or pulsed DC to be outputted from the stator. Only a shorted diode will output AC only with no pulsing DC.

When diode is working correctly it rectifies the AC into a half DC pulse voltage which the battery which acts as a large capacitor smooths out into near pure DC and very small AC ripple voltage. Actually most meters only reads average voltage and peak voltage; therefore, the average DC voltage out of this half wave rectifier setup is only = AC reading x .707 when the battery is not present. This because the output is going from 0 to peak and back 0 at 30 times a second (3600 rpm) or less depending on the rpm. Once the battery is added and it charges then the meter reading be higher as it will not read less than the battery voltage. Current to the battery will drop to zero whenever the output voltage from the stator drops below the battery voltage.

This like saying a wire has a short in it when wiggled causing the voltage drop outs when in fact it is open circuit occurring during the wiggle test.
 

bertsmobile1

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Thank you Star
My typo has been corrected
 
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