Need to know how many volt my alternator is producing. So how do I check the voltage. I have a voltage meter. Hope somebody can help me with this one. Now that got my ac working the blower speed slows down when I turn headlights on. I do notice the battery cranking amps is lower that what it should be. (540) Im thinking I need to replace battery with higher cranking amps for ac car. Does anybody know what size of battery would work better?
Start with this basic test before you go deeper: With your car running, and in park, measure the DC Voltage across your battery terminals. You should have around 14.3 volts DC. With your engine off, you should measure a little more than 12 volts on your battery. Let us know how these measurements check.
Yes that exactly what it measures but when I turn the lights and ac on , the ac blower slow down and it won't go up again until I accel. again. My question is should I install relays on my headlights or the alternator not producing enough amps?
Not enough amps. Several possibilites. 1. Alt not producing enough (but it sounds like it's ok when you get it spinning faster). 2. The regulator not regulating (but it sounds like it is when the lights do get brighter when the alt is spinning faster). 3. Idle is low 4. Pulley is big 5. My money is on 4 and 5
Exactly! A good auto parts store should be able to test the amperage. I have an old amp gauge I use, you hold it beside the wire and it tells you the reading. I just ran my car with the headlights on, and the fan on full, it was only drawing 1.45 amps.
Another simple test that you can do is to measure the AC Voltage across your Battery terminals, with the engine running, and look for less than .5 Volts AC (less than 1/2 Volt AC). Less than .5 Volts AC is good. What this test shows, is whether you have a relatively smooth rectification pattern on the output of your Alternator, and ultimately, whether you have a bad winding, or bad diode in the Alternator. If a Diode is shorted, or open, in the Alternator, the Output waveform will have an irregular waveform, that can be spotted with an oscilloscope, but it is easier and quicker to just look for less than .5 Volts AC. There is also an adjustment inside your Voltage Regulator, that controls your Charging Voltage and rate, but it sounds like your Voltage Regulator is fine. There is also a test where you can bypass the Voltage Regulator, and isolate a charging problem to just the Alternator, but it doesn't sound like you need to do this in this case. It was common for the older charging systems, with the low Amp output Alternators, to produce dimmer lights, and slower heater fans, when idleling at a stoplight. It was important for the Batteries, in these older systems, like your car, to have a Good Battery to assist the charging system, during these low idle conditions. You might have your Battery checked for it's ability to produce enough Amps. If you do take your Alternator out to have it checked, make sure you disconnect the Battery terminals before doing this, to avoid damaging the Alternator, and don't disconnect the Alternator cables while the engine is running either. Good Luck...let us know what you find.
I did the test and is .37 which I assume is good alternator. So maybe is my battery. I will have it check. Thanks for all the help.
not sure if this would help but when I changed the pulley on my alt to a larger one I notice lights dim at idle and the voltmeter shows 12.5 volts and I go to 13.5 once I start driving.
How many amps is the alt capable of producing? I have a sim setup w/ sub-amp and elec fan. I have not noticed any change in my blower speed at night w/ the ac running. I do have a new 130 amp alt.
the other problem is the 40 year old wireing in these has an increasing resistance. this happens from carrosion in all the connections in the harness. you can doctor this by puting relays on high amperage draw things like the head lights, and air conditioning compressor,
