Sonny
It’s all fun til the rabbit gets the gun.
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Question about voltage regulator and charging
- Thread starter Sonny
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STOP, STOP, STOP! What are you working on? Read & Learn, Good Luck.
http://www.imperialclub.com/Repair/Electrical/charging.htm
http://www.imperialclub.com/Repair/Electrical/charging.htm
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What are you referring to, the ignition system or the charging system ?
Sonny
It’s all fun til the rabbit gets the gun.
Charging system. Car runs great. It’s a ‘70 Belvedere. Just wondering if 13.5 v is what the battery would charge at. Voltage at the alt output stud is 14.2. It’s also the correct 2 terminal (blue and green wire) alt., new module and electronic ignition upgrade harness and ballast resistor.
13.5 is fine with a charged batt
PurpleBeeper
Well-Known Member
I believe he's testing voltage across the +/- of the battery while the engine is running. Sonny, I think you're just fine at 13.5V
Sonny
It’s all fun til the rabbit gets the gun.
Thanks. That is what I was doing.
Wietse
Well-Known Member
You measure 14.2 on the alternator and 13.5 on the battery, the difference are losses in the wiring and connections.
The alternator charge passes through the firewall connector (and amp meter) so if there are any old, corroded connections they cause the voltage drop.
If you make sure they are all clean and tight you might see an increase in voltage on the battery.
If you keep the engine revs up at 2000 rpm, does it show more voltage?
The alternator charge passes through the firewall connector (and amp meter) so if there are any old, corroded connections they cause the voltage drop.
If you make sure they are all clean and tight you might see an increase in voltage on the battery.
If you keep the engine revs up at 2000 rpm, does it show more voltage?
QQBlue1
Well-Known Member
If I may add a question since I'm having an issue similar to Sonny.
I'm working on a 68 Charger with a 318. At idle I have 13.6 volts at the battery (which is brand new) and the ignition side of the voltage regulator and with the lights on it drops to 12.7. With the lights off and rpms up to 2500 or so, I get no more than 14.20 volts.
The alternator grabs my screw driver magnetically, but field post it is only putting out 12.00. It reads the same at the field side (dark green wire) of the voltage regulator and drops to 10.60 with the lights on.
The alternator is relatively new, but has been sitting for 2.5 years and was exposed to plenty of dust. The car has cut out on me a few times while I was driving it, but restarted a few minutes later. Ignition wiring looks good as does the bulk head connections.
I suspect a faulty alternator. However, I admit that I still have the original front wiring harness in the car. Maybe its time to upgrade it.
I'm working on a 68 Charger with a 318. At idle I have 13.6 volts at the battery (which is brand new) and the ignition side of the voltage regulator and with the lights on it drops to 12.7. With the lights off and rpms up to 2500 or so, I get no more than 14.20 volts.
The alternator grabs my screw driver magnetically, but field post it is only putting out 12.00. It reads the same at the field side (dark green wire) of the voltage regulator and drops to 10.60 with the lights on.
The alternator is relatively new, but has been sitting for 2.5 years and was exposed to plenty of dust. The car has cut out on me a few times while I was driving it, but restarted a few minutes later. Ignition wiring looks good as does the bulk head connections.
I suspect a faulty alternator. However, I admit that I still have the original front wiring harness in the car. Maybe its time to upgrade it.
Stock alts are really unefficient while in iddle ( for voltage and even worst for amperes ). That's the culprit for LOT of electrical issues and burnt spots on our cars believe it or not
Wietse
Well-Known Member
QQBlue1: The alternator is controlled by the voltage measured on the IGN side of the voltage regulator.
If it is low, it controls the alternator to charge, if it is ok he regulates the alternator back.
Voltages seen across the wiring all refers back to the IGN side of the VR, as an example, you might see 16 volt on the battery (overcharge) and at the VR you measure only 10 volt.
This 10 volt causes the VR to set the alternator to charge, causing an overcharge because it shows it is low.
Issues like this are commonly caused by poor connections (corrosion, etc.) in the wiring between the VR, ignition key and all other connections on that supply.(Also the VR can be faulty, best to replace it with a "new" type which has the modern components inside instead of the old mechanical switch)
As you mentioned it goes up to 14.2 volt when engine is revved up which is a good reading, as Nacho mentioned the alternators perform poor while at idle.
When switching the lights on it draws a lot of power and the voltage drops but the alternator has no power to do something about it while engine is idling.
If you measure across the wiring make sure the conditions remain same, so keep the lights off/low idle or revved up, take all measurements on VR, battery and alternator.
You can repeat the same with the lights on/low idle or revved up but you cannot compare the readings on a certain place under different conditions.
An old wiring harness can cause trouble if it has been cut up and has corroded connectors.
Alternators can handle some dirt, they get exposed to all sorts of **** under the hood as well, moisture, bugs and spider getting in there, dust and sand flying around.
As long as the winding coating is in good condition there should be no issues caused by these things.
If it is low, it controls the alternator to charge, if it is ok he regulates the alternator back.
Voltages seen across the wiring all refers back to the IGN side of the VR, as an example, you might see 16 volt on the battery (overcharge) and at the VR you measure only 10 volt.
This 10 volt causes the VR to set the alternator to charge, causing an overcharge because it shows it is low.
Issues like this are commonly caused by poor connections (corrosion, etc.) in the wiring between the VR, ignition key and all other connections on that supply.(Also the VR can be faulty, best to replace it with a "new" type which has the modern components inside instead of the old mechanical switch)
As you mentioned it goes up to 14.2 volt when engine is revved up which is a good reading, as Nacho mentioned the alternators perform poor while at idle.
When switching the lights on it draws a lot of power and the voltage drops but the alternator has no power to do something about it while engine is idling.
If you measure across the wiring make sure the conditions remain same, so keep the lights off/low idle or revved up, take all measurements on VR, battery and alternator.
You can repeat the same with the lights on/low idle or revved up but you cannot compare the readings on a certain place under different conditions.
An old wiring harness can cause trouble if it has been cut up and has corroded connectors.
Alternators can handle some dirt, they get exposed to all sorts of **** under the hood as well, moisture, bugs and spider getting in there, dust and sand flying around.
As long as the winding coating is in good condition there should be no issues caused by these things.
QQBlue1
Well-Known Member
Thank you Wietse and Nacho-RT74. My Voltage Regulator has the modern components. I went through another series of tests:
At 1200 rpms I had 14.7 volts at the alternator (+ probe on the post leading to the battery and - probe grounded to the back of the alternator case) and 14.10 at the battery and ignition side of the regulator.
At 2500 rpms it was 15.40 at the alternator and 14.30 at the battery & regulator.
At 800 rpms there was a lot of variation again as Nacho mentioned, anywhere from 13.10 to 14.50 at the alternator and 12. 80 to 14.00 volts at the battery & regulator.
There was a consistent .5 voltage drop through the wiring harness, and with the lights and blinkers on it lost another volt. Plus, with the blinker on the ammeter in the dash bounced around quite a bit. Nevertheless, I ran the car around town for 45 minutes today with no issues. Perhaps the bottom line is that unreliable charging at idle and the previous battery (which had a bad cell) was simply a problematic combination but with the new battery and keeping an eye on the idle rpms I should be okay. At least I hope so, the car kind of has me spooked since it died a few times while I was cruising at low speeds with the old battery.
At 1200 rpms I had 14.7 volts at the alternator (+ probe on the post leading to the battery and - probe grounded to the back of the alternator case) and 14.10 at the battery and ignition side of the regulator.
At 2500 rpms it was 15.40 at the alternator and 14.30 at the battery & regulator.
At 800 rpms there was a lot of variation again as Nacho mentioned, anywhere from 13.10 to 14.50 at the alternator and 12. 80 to 14.00 volts at the battery & regulator.
There was a consistent .5 voltage drop through the wiring harness, and with the lights and blinkers on it lost another volt. Plus, with the blinker on the ammeter in the dash bounced around quite a bit. Nevertheless, I ran the car around town for 45 minutes today with no issues. Perhaps the bottom line is that unreliable charging at idle and the previous battery (which had a bad cell) was simply a problematic combination but with the new battery and keeping an eye on the idle rpms I should be okay. At least I hope so, the car kind of has me spooked since it died a few times while I was cruising at low speeds with the old battery.
Get an alt able to give 40-45 amps iddling and you'll notice the HUGE difference. If more better, but 40-45 amps iddling is the minimun I advice. THAT DOESN'T MEAN you will have the alt sourcing 40-45 amps iddling but will be capable if needed. That will guaranteed to you less ammeter flickering and more consistent voltage all around
Is the same than a big batt able to give 150-200 amps as cranking power, which doesn't mean is giving that power allways, just able to do it if requested. Your batt is able to light up a side marker the same than give the power to the starter motor... and won't burn the bulb! well. The same to the alt!
Is the same than a big batt able to give 150-200 amps as cranking power, which doesn't mean is giving that power allways, just able to do it if requested. Your batt is able to light up a side marker the same than give the power to the starter motor... and won't burn the bulb! well. The same to the alt!
Wietse
Well-Known Member
Them readings do read ok, although you have a consistent drop of 0.5Volt, which is still a little high. (0.1 - 0.2 Volt is acceptable)
You can get it lower by going through all connections and clean them up and make sure it is tight.
It will not solve any issue, but does give the best feedback to the alternator for charging cycle.
Guess at idle it will remain a pain in the *** with these alternators.
I did replace my alternator with a 70-75 Amp model from Summit which is doing better, also at idle.
I had major issues with all this when I bought the car, battery overcharged, voltage regulator not working and all wiring in very bad state...replaced the whole lot. (had over 16 Volt on the battery when revved up)
Another side note, up to you if you want to do this or not: I did the Amp meter by-pass (As many others did) just for the simple reason it could be a high potential for a short and cause a fire in the dash.
This is because the dash frame (aluminium) is in contact with ground, the posts on the Amp meter (+) have these small plastic washers in between to avoid contact.
As a lot of people say, if maintained well nothing can happen which is true, but to me the Amp meter does not provide me anything that is worth more then the risk of a fire.
I did install an extra volt meter on a separate panel under the dashboard to keep an eye on the alternator is working or not.
You can get it lower by going through all connections and clean them up and make sure it is tight.
It will not solve any issue, but does give the best feedback to the alternator for charging cycle.
Guess at idle it will remain a pain in the *** with these alternators.
I did replace my alternator with a 70-75 Amp model from Summit which is doing better, also at idle.
I had major issues with all this when I bought the car, battery overcharged, voltage regulator not working and all wiring in very bad state...replaced the whole lot. (had over 16 Volt on the battery when revved up)
Another side note, up to you if you want to do this or not: I did the Amp meter by-pass (As many others did) just for the simple reason it could be a high potential for a short and cause a fire in the dash.
This is because the dash frame (aluminium) is in contact with ground, the posts on the Amp meter (+) have these small plastic washers in between to avoid contact.
As a lot of people say, if maintained well nothing can happen which is true, but to me the Amp meter does not provide me anything that is worth more then the risk of a fire.
I did install an extra volt meter on a separate panel under the dashboard to keep an eye on the alternator is working or not.
Well, an ammeter provides such more instant and straight info about the batt charging/discharging status than a voltimeter ;)
Isolators on ammeter are not plastic but masonite. Plastic is dangerous because can melt.
As far you get an alt able to provide all the power requirements, the ammeter barelly will get load readings.
More here:
http://www.dodgecharger.com/forum/index.php/topic,33574.0/all.html
Isolators on ammeter are not plastic but masonite. Plastic is dangerous because can melt.
As far you get an alt able to provide all the power requirements, the ammeter barelly will get load readings.
More here:
http://www.dodgecharger.com/forum/index.php/topic,33574.0/all.html
if you wanna keep stock look and a bit more efficient alternator but on the cheap get one of the earliers 80s alt, designed to provide around 80 amps and you'll be satisfied. Be sure it gets small diameter pulley to spin faster. These alts can be found on $50-80 rate
https://www.hotrod.com/articles/mopp-0112-electronic-voltage-regulator-and-alternator/
could just need a slightly longer belt, because these are a hair wider and will need to sway the back of the alt from the block. Could need to trim a bit the rear spacer for best aligment
EDITING... search at rockauto and select any earlier 80s Dodge car with bigger engines and you'll find 78 amps alt, remanufactured $55. pic shows big pulley, but can be changed... I found one ACDELCO PN 3342218
https://www.hotrod.com/articles/mopp-0112-electronic-voltage-regulator-and-alternator/
could just need a slightly longer belt, because these are a hair wider and will need to sway the back of the alt from the block. Could need to trim a bit the rear spacer for best aligment
EDITING... search at rockauto and select any earlier 80s Dodge car with bigger engines and you'll find 78 amps alt, remanufactured $55. pic shows big pulley, but can be changed... I found one ACDELCO PN 3342218
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Wietse
Well-Known Member
I knew it was no plastic, but had no idea how you call that material...now i know
Depends how you look at the function of the volt meter, if the voltage is over 13 Volt it means the alternator is working, if it is 12v or below there is something wrong and you are on battery only.
If, for any instance the v-belt snaps there is low voltage from battery only, and in that case it also means the engine is getting no cooling because the pump is not driven as well.
If you include an low voltage alarm, set at 12.5Volt, you will know straight away to stop because it could be the belt snapped and you are in time before the engine overheats.
An Amp meter just shows discharge when the belt snaps but it can show discharge at any given time, it just tells you the consumption vs. supply.
Just my 2cts, i am quite ***** about alarms, got an additional low oil pressure buzzer and the low voltage buzzer.
an ammeter indicates you when the battery is being discharged ( or charged if got previouslly discharged and alt is being able to refill it ), which it means not enough output form alt at any speed or a total failure, depending how big is the discharge reading.
You can get a light discharge reading and your alt still working nice, voltage included... just slowly draining your batt due the low amps output ;)
perfect status... death centered amm needle at any speed. It means batt is full and not being sucked and alt sourcing everything
You can get a light discharge reading and your alt still working nice, voltage included... just slowly draining your batt due the low amps output ;)
perfect status... death centered amm needle at any speed. It means batt is full and not being sucked and alt sourcing everything
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sharing one experience between amm and volt readings
Once I got an alt failure... was getting a 18 to 24 volts reading ( with a multitester not a car gauge ) depending on rpms. If you had a voltimeter would say IS OVERCHARGING!! right ?
my ammeter was reading a heavy discharge, and some slight charge reading when reving up up to 2K. That's what actually warned me up because I don't have a volt gauge
Disconected the batt and engine stalled.
what it was the truth? overcharging because the 18 volts reading or discharging per the amm reading ? If overcharging the engine shouldn't stall
the problem was one of the vents vanes getting friction with stator leads while spinning, causing a short inside the alt. Of course that was posible to read it just spining, because on bench without spin it everything was perfect. I took care of that manually spinning the alt and feeling that small frictions in hands. It took me about an hour to find out that because it wasn't easy to feel that friction on alt case!
so, hence the reason why I preffer the ammeter NOT SAYING voltimeter doesn't work, but...
Once I got an alt failure... was getting a 18 to 24 volts reading ( with a multitester not a car gauge ) depending on rpms. If you had a voltimeter would say IS OVERCHARGING!! right ?
my ammeter was reading a heavy discharge, and some slight charge reading when reving up up to 2K. That's what actually warned me up because I don't have a volt gauge
Disconected the batt and engine stalled.
what it was the truth? overcharging because the 18 volts reading or discharging per the amm reading ? If overcharging the engine shouldn't stall
the problem was one of the vents vanes getting friction with stator leads while spinning, causing a short inside the alt. Of course that was posible to read it just spining, because on bench without spin it everything was perfect. I took care of that manually spinning the alt and feeling that small frictions in hands. It took me about an hour to find out that because it wasn't easy to feel that friction on alt case!
so, hence the reason why I preffer the ammeter NOT SAYING voltimeter doesn't work, but...
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