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Electrical issue over charging
So my optima was having issues starting the car at 3.5 years old. I took it in for testing and they said it tested good but was low on charge. I took the alternator in for testing and they hooked it up wrong to begin with but then remedied it and the unit tested good on their machine.
At that point I bought a new lead sealed battery and installed it and started the car back up. I found the amp meter running high at higher rpm’s and shut it back down. I have a external voltage regulator and figured I had lost it again as I had many years ago. When the car is at idle the battery voltage is about 12.8 but when I put any rpm’s to it it can soar to 16.6. The amps also can go to 25-50 depending on rpm’s I unplugged the voltage regulator and put a new one on and it still is doing the same thing. I have a 351 bored to a 393 stroker with a 4 wire hookup at the alternator and a 4 wire hookup at the regulator. Any ideas on where to test first? Thx Kirk |
I could be wrong, but I don't think a standard alternator is capable of producing 40-50 volts.
But, nearly every stock alternator is fully capable of producing 40-50 amps. If you have an amp meter, it might be reading a bit low. If you have a volt meter, there's a problem. |
Sorry amps are soaring and volts go to about 16.5 with enough rpm’s
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I had a similar issue and it turned out my connection from the wiring harness to the voltage regulator was poor. The wires inside the plastic cover were not super tight and as I plugged in the VR it just pushed one or more out of the way.
After I remedied that, battery voltage while running returned to normal, around 14.5V. |
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What is your ammeter reading at idle? |
It hardly reads any charge at idle but when I put that much voltage to a brand new fully charged battery something is wrong. I charged it with my charger to the max before the install, and putting 16+ volts to the battery is wrong.
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The alternator makes as many amps as the system needs, up to whatever it's rated at. If you're drawing a lot of power - electric pumps, EFI, fans, etc - then it will produce amps enough to feed them all. Look at all the things that are running, and add them up. See if it's pretty close. If not, you've got an unknown amp draw somewhere.
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So your Superformance has a voltmeter and an Ammeter? Are you using a Multimeter for the voltage. If so where are you attaching the meter?
Strange readings as your voltage is climbing the as the Amps go up too. Normally as voltage increases the amps go down. Work performed (watts / voltage = amps) Much like a 110vac compressor needing 20amp CB, and then rewire the motor for 220vac it only needs a 10amp CB. Are you sure the new battery is fully charged? Is your charger a smart charger? or least the amp reading at the 10amp setting should be reading zero. Last thing: When this started you had a 3.5yrs low charge battery. Then you pulled the alternator for testing. Is it reconnected properly? Rule of thumb in aircraft maintenance. If you fix a squawk and now have a new squawk. Go back the check what you touched last. |
Check the chassis ground connection near the battery. It’s between the battery box and the tail light. You can feel the bolt head thru the carpeting. Also check the battery post connectors. There is also a ground on the voltage regulator (brown wire to bolt) start with this and keep us informed….
Blas |
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Remember, the ammeter is showing you the total output of the alternator - not just what's going to the battery. That includes all electrical equipment. |
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Disconnect the ammeter
ammeters were used on cars with generators with no need for a high output as the power needs were minimal. when high output alternators came about you do not use them and have a voltmeter instead. A overheating condition can happen as all the power(amps) pass through 1 little wire and ammeter and will burn down your car. Not a good idea to still use an ammeter. You also need a fuse link out of the alternator to protect the car wiring.
amps used in old car; heater fan-5 amps; lights-6 amps; ignition 4 amps; radio-1 amp; total 16 amps. amps used in modern car; heater/ac-10 amps; rad fan -25 amps; lights -6 amps; ignition- 8 amps; ecu- 5 amps; abs ecu-5 amps; radio/stereo -10 amps; power windows-10 amps; power seat- 6 amps; fuel pump 6 amps; wipers 4 amps; total 95 amps.*so a 100 amp 1 wire alternator would be needed. Perry |
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"For most applications, the advantages of a THREE-WIRE alternator will far outweigh the little time saved with a ONE-WIRE installation." "Both types have the voltage regulator in the alternator, but there are important differences between the ONE-WIRE and THREE-WIRE systems." "The THREE-WIRE advantages are even more important in recent years – more powerful alternators are often installed on Hot Rods and they must support a more power hungry electrical system." More: Catalog Note: This is a 3 page article - don't skip pages 2 & 3. I'm very happy with my 130 amp, 3-wire Ford 3G alternator and see no reason to downgrade. |
This is an excerpt from the catalog link provided By Cycleguy55:
The system only works properly when the “battery charging wire” connects from the junction to the battery. There will never be a wire connected from the alternator directly to the battery. By now the thought may have occurred, that a possible installation could include a heavy gauge charging wire from the alternator directly to the battery. And then leave in place the original wire from the alternator to the factory main junction. Route the voltage sensing wire to the junction, in effort to keep the lights and ignition happy. It’s true that then voltage regulator would maintain the junction at the 14.2 level. However, the fault in the plan is with the voltage drop that will occur between the alternator and the junction. As was previously discussed, the system will compensate by raising the voltage level at the alternator. The problem would be overcharging the battery through the separate charging wire, as voltage at the back of the alternator could be over 16 volts. |
chrome?
If you have a chrome alt then file the chrome off where the long bolt goes into the head so it is bare metal to head contact. That is a high resistance point and will not give regulator a correct reading. I know!
Perry :cool: |
So I found my issue…. When I removed the voltage regulator off there was a wire with a lug bolted to the mount stud. I ASSUMED this was the ground wire for the regulator, but what I did not see was the wire underneath that was the ground wire running to the ground stud on the alternator. It had busted the lug off.
So the regulator was not grounded and the other wire must run somewhere that needed a ground also. Everything is running as normal now. |
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And thanks for reporting the fix!!! So many people come here about issues but never follow up to see how good the peanut gallery is at remote trouble shooting :)
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Thanks for the input guys but the one that stuck with me was what did I do and what did I work on to possibly screw this up.
Lol |
Simple problem and simple fix. That happens.
Your thought of 'what did you do' and 'how could that have caused the problem' is something we should all keep in mind when we run into trouble. |
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