What causes the alternator to over charge? I replaced the alternator and voltage regulator

If the battery is not being properly charged while unit is running, it will go dead. You may have a problem with the voltage regulator or magneto causing the no charge issue

1985 WOW ! does it run at all ? if it does , check battery voltage, should be between 12---14 volts, check alternator also, a parts store can do this for you ! is your regulator outside your alternator ? cause most new alternators have them inside the alternator ! just thinking out loud, but stranger things have happened ! are these new parts the correct ones for your make & model ? battery terminals clean, tight ! make sure all GROUNDS are good ! very important ! what condition are your battery cables ? is your BELT good, tight, not slipping !!! sure your starter & solonoid OK ! not shorting out, from dirt, grease, oil, etc., all fuses OK! I think we covered it, take your time, go over what I mentioned, see it you find the problem, good luck !

Due to the nature of the battery technology used with vehicles the alternator is mostly incapable of charging the battery. The car alternator is designed to keep a fully charged battery fully charged and to provide all the power for the car equipment.

The alternator charge rate is regulated by a voltage regulator. Because the alternator output is connected to the battery, the alternator and battery voltage will be the same and the voltage regulator monitors that voltage.

The lower the battery voltage the more output the alternator will produce in order to correct the situation but because a lead acid battery has a high internal resistance to accepting a charge the terminal voltage will quickly rise to the alternator regulated voltage and fool the alternator into thinking the battery is fully charged when the output will drop to the order of just a couple of amps.

Switch on the headlights or a similar load that will lower the battery voltage and the alternator will increase it's output again - but only by the amount of current the headlamps or other load is consuming.
It matters not what the alternator rated maximum output is, it is designed to provide only the necessary current and no more.

The only time an alternator should ever need to produce maximum output is when on a dedicated testbed and then only for a short duration to avoid damaging the unit. Testing the current output on a modern vehicle is not recommended except for the regulated voltage testing and a rule-of-thumb output test where all equipment is switched on and the engine speed raised while the battery voltage is monitored.

Most modern alternators use an internal voltage regulator but a few systems use a separate voltage regulator. No alternator rebuild would be complete without a regulator test and probably a new or replacement regulator, which is where the majority of charging system problems are, or the brush gear.
Assuming the wiring is ok, no alternator should suffer any harm if the voltage regulator and auxilliary diodes (if fitted) are in good order though fitting a defective or a discharged battery can cause it to overheat and be damaged.

The alternator usually just about stops producing an output when the battery voltage is in the region of 14.5/14.8 volts.
Your description indicates the voltage regulator is not working correctly - unless 40 amps was being consumed by the car equipment the alternator should not have been producing 40 amps.. I suggest you also have your battery tested

The max charge voltage is usually around 14.5 volts, so 14.4 is not high.
Its possible the battery has a dead cell and that is causing the acid problem.
You might want to check with the dealer on what the max voltage is for your car.

Alternator maybe charging , but not enough to keep the battery charged which is causing the battery to drop charge. Most likely it's the voltage regulator inside the alternator. but regardless the whole alternator will have to be replaced. This will eventually cause the new battery cells to go bad.

I'm assuming you mean the charging voltage indicator. This is an indication of an incorrect charging voltage (too high, should be from 12.5 to 14 volts). This problem is most likely caused by a bad charging voltage regulator. There are two variations of the location of the regulator: 1) regulator is outside of the alternator and located on right side of the engine compartment on the wheel-well, below the starter relay or 2) The regulator is inside the alternator (in which case you'd have to replace the alternator).

It sounds like you have done a whole lot of replacing and not much "diagnosing". Did you chech for battery voltage at the alternator? There should be battey voltage at the large Black/Orange wire that is on the B+ terminal of the alternator. This wire should have voltage all the time. If there is no battery voltage, you most likely have a burned fusible link at the starter relay area.
There should also be voltage at the "S" terminal with the ignition on. If there is no voltage, then check for voltage at the "S" terminal of the voltage regulator. If there is no voltage at the "S" terminal on the voltage regulator then check the "I" terminal on the regulator for voltage.

NOTE: The voltage on the "S" terminal should be 1/2 that of the voltage on the "I" terminal.

If there is voltage on the "I" terminal, make sure your voltage regulator is grounded properly to the fender and retest to see if it is charging the battery. If it is still not charging, disconnect the regulator connector and connect a jumper between the "A" and "F" terminals of the connector. Start the engine. The alternator should now be charging the battery at high voltage (usually over 15 volts) If it does, replace your voltage regulator. If it does not, then you need to check your wiring between the voltage regulator and the alternator.

Please also review this article:

What Else Could Be Wrong?

A bad voltage regulator could cause the problem. Assuming the alternator is working correctly. Jump the vehicle with the battery disconnected and then disconnect the jumper cables. If the vehicle dies your voltage regulator or Alternator are bad, some vehicle have separate regulators from the alternator, if it continues to run the alternator is good but the voltage regulator is probably the cause.

it is probably the regulator which is bolted on to the alternator

Are the connections really dirty at the voltage regulator? These tend to get corrosion on them and cause weird charging system issues. Also make sure the ground is good on the regulator.