[C2] vr
Thread Starter
Intermediate
Joined: May 2020
Posts: 36
Likes: 8
From: Ft Mitchell,Ky
vr
I have a 67 small block, original owner. I have gone thru 4 VR, 3 delco, 1 standard ignition. Alternator output-12.5v. Rev engine to 1500 and get 40+ amp charge that does not decline. Question, what should the charge voltage be at 700 rpm. Is the charge voltage rpm sensitive. ?what should the max output voltage be.
I’m stumped. Had the alternator checked twice by different shops. Had the battery checked twice and lastly charged to full charge. Always the same results. Tried an additional ground ground jumper. No change.
HELP please
jt
I’m stumped. Had the alternator checked twice by different shops. Had the battery checked twice and lastly charged to full charge. Always the same results. Tried an additional ground ground jumper. No change.
HELP please
jt
Thread Starter
Intermediate
Joined: May 2020
Posts: 36
Likes: 8
From: Ft Mitchell,Ky
VR maybee
I am the original owner of a 67 small block. I have a problem I can’t figure out. I have gone through 4 VR, 3 delco and a standard ignition. The problem- At idle(700 rpm) the alternator puts out 12.4v. I have had the alternator checked by 2 different shops as well as the battery twice. Both ok. I have put a second ground on the VR. Nothing changes. 12.4 at idle and a slight negative on the ammeter. Rev to 1500 and the amp gauge goes to 40+ and never comes down.
what gives?
jt
what gives?
jt
Le Mans Master
Joined: Feb 2014
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From: Richardson Texas
You're asking about amps and then talking about volts...which one are you concerned with? A non-A/C alternator is rated around 40 amps. Alternator should be putting out 13.8 to 14.2 volts regulated to the battery. Battery should have a stand alone voltage around 12.5 volts...fully charged.
Team Owner
Joined: Jul 2006
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From: Kannapolis NC
I think I understand what you are asking. You want to know if the positive swing of your battery gauge means your battery is overcharging.
I answered your direct question of how much should the battery voltage be at idle in the other thread. Leif answered it again in this one. Do this: With the key off, measure the voltage across your battery with a voltmeter. Post here what you get. Start your car, measure the voltage across the battery at idle, post here what your battery gauge is showing after the car runs for a minute or so. Now rev the engine a couple of thousand rpm's and measure the voltage across the battery at that rpm and post what that voltage is and what the battery gauge is doing. From these three steps, we can tell what is happening with your gauge and battery symptoms. Post only those three situations I listed for now and then we may have other questions depending on what answers you get.
I answered your direct question of how much should the battery voltage be at idle in the other thread. Leif answered it again in this one. Do this: With the key off, measure the voltage across your battery with a voltmeter. Post here what you get. Start your car, measure the voltage across the battery at idle, post here what your battery gauge is showing after the car runs for a minute or so. Now rev the engine a couple of thousand rpm's and measure the voltage across the battery at that rpm and post what that voltage is and what the battery gauge is doing. From these three steps, we can tell what is happening with your gauge and battery symptoms. Post only those three situations I listed for now and then we may have other questions depending on what answers you get.
Thread Starter
Intermediate
Joined: May 2020
Posts: 36
Likes: 8
From: Ft Mitchell,Ky
Vr
T following is the data I collected per tour instructions:
With key off the battery shows 12.43v
at idle the battery reads 12.22v @ ~o+ amps
at 1000 rpm the battery reads 12.19 v @~ 0- amps
at 1500 rpm the battery reads 12.8 v @~ 15 amps
at 2000 rpm the battery reads 18.4 v @ 40+ amps
Reversing
at 1500 rpm the battery reads 15.9 v @ 20 amps
at 1000 rpm the battery reads 12.85 v @ 0 amps
at 700 rpm the battery reads 12.59 v @ 0 amps
hope this helps
jt
With key off the battery shows 12.43v
at idle the battery reads 12.22v @ ~o+ amps
at 1000 rpm the battery reads 12.19 v @~ 0- amps
at 1500 rpm the battery reads 12.8 v @~ 15 amps
at 2000 rpm the battery reads 18.4 v @ 40+ amps
Reversing
at 1500 rpm the battery reads 15.9 v @ 20 amps
at 1000 rpm the battery reads 12.85 v @ 0 amps
at 700 rpm the battery reads 12.59 v @ 0 amps
hope this helps
jt
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Someone might have replaced the harness connector and miswired the pins, wrong regulator, wrong harness or defective regulator as mentioned above. Start with the easy stuff. Using the wiring diagram above see that your regulator wires are the same color going to the same pins and end up at the correct terminals on the alternator, ect, as shown. If so, replace the regulator and report back.
Dan
Dan
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If you are certain its wired right its time to full field the alternator to see if it works. Set your digital volt ohm meter up across the battery set to DC volts. Unplug the two wire connector from the back of the alternator. Use a jumper wire between the output stud on the alternator and the F terminal of the alternator. Speed up the engine and look at the voltmeter. You now have the regulator bypassed and you are commanding the alternator to go to full output. You should see about 15 to 17 volts. If you don't you have a dead alternator.
Dan
Dan
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From: Kannapolis NC
If you are certain it’s wired right it’s time to full field the alternator to see if it works. Set your digital volt ohm meter up across the battery set to DC volts. Unplug the two wire connector from the back of the alternator. Use a jumper wire between the output stud on the alternator and the F terminal of the alternator. Speed up the engine and look at the voltmeter. You now have the regulator bypassed and you are commanding the alternator to go to full output. You should see about 15 to 17 volts. If you don't you have a dead alternator.
Dan
Dan
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