42 amp alt ford 302 engine

Jakem

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What do we make of this issue
 

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Scott Danforth

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Have the alternator tested. My last rebuild went back twice. Two bad regulators out of the box
 

sam am I

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There might be a bad diode(output seems a little low) perhaps creating enough extra noise to make the meter jump around, but also think its the meter having sampling issues with a bit extra alternator noise ........If this measurement is from the B+ of the alt., then of course the battery is connected to this wire and with good/clean connections yet your meter is flipping around as low as 0.26V, 0.63V, 1.63V while connected to a 12V lead acid battery? Not entirely real readings, the 12V lead acid ain't going to drop like that, not that fast and esp not that low.
 
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dingbat

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Nov 20, 2001
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...If this measurement is from the B+ of the alt., then of course the battery is connected to this wire and with good/clean connections yet your meter is flipping around as low as 0.26V, 0.63V, 1.63V while connected to a 12V lead acid battery? Not entirely real readings, the 12V lead acid ain't going to drop like that, not that fast and esp not that low.
Agree…if the battery isn’t connected it could be the regulator bouncing around trying to regulate w/o a load.

Couple of points about the meter:
2.5 second update rate
No auto ranging - manually select DC or AC
HV - high voltage or DC - not shown on display in picture


Would like to see same test done with a load on the circuit
 

Jakem

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had it tested...no good...I bought a rebuilt self exciting 1 wire for 160 bucks. Works great
 

Scott Danforth

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Make sure you have a battery disconnect switch with a 1-wire alternator
 

Jakem

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I will get a new one and install it. I had one but it seemed broken on the inside. Didn't trust it.
 
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