Had charg diag done said it was voltage reg. Replaced it redid diag still says volt reg

Some vehicles are fitted with a smart charging system that is designed to prevent the alternator charging during acceleration to free a few horsepower to help.

My experience of these is very limited but there is an ECU that controls them and the battery, charging or ignition light using information from the engine management system.
The alternator generally has an extra plug with about four or five wires which when disconnected render the alternator a standard machine sensed type.

Japanese vehicles used separate voltage regulators longer than most types. You either need experience or a wiring diagram for good fault diagnosis but mostly it is unnecessary to check the charging current of an alternator which bears little significance unless being tested with a graduated load or adjustable carbon pile.

The current output of a healthy alternator is dependent on the terminal voltage of the battery which in turn is dependent on the electrical load placed upon it. Switching on the lights should lower the voltage and increase the alternator output. If the battery is particularly good the voltage won't fall very much and the current won't increase as much as expected...

Measuring the battery voltage with the engine running at about 2000/2500 rpm is sufficient for most purposes. With nothing switched on and a fully charged battery it should be around 14.5 volts and with everything switched on (lights, HRW, heater fan, etc.) a healthy alternator should continue to maintain a voltage above that of a healthy fully charged battery (13.2 volts).

If the voltage isn't maintained on load the charging system, probably the alternator, is faulty and should be independently tested.

The alternator is probably junk, it happens; should charge 13.5 to 15.5 volts

diodes do not regulate charge
simply put diodes are one way valves for electricity and are used to rectify alternating current (AC) to direct current(DC)
you use a voltage regulator after a rectifier pack to control the voltage from an alternator of maintain a max voltage of 14.5 volts dc
take it to an accredited bike electrician

nothing wrong with the ECM unless it has the voltage regulator as part of the system
indicates faulty wiring and faulty alternator
have a load test done on the battery
have an auto electrician do a full charging system check
charging voltage should be 14.5-14.8 volts DC
battery voltage should be 12-13.5 volts dropping to 11 volts when cranking the engine
make sure that the drive belt tension is correct and the belt is in good condition

The battery voltage needs to be checked.Also if battery is very old and not replaced for very long, then just get the battery replaced.Approx battery life is 3 years.If its very old battery then try new battery. But if battery is new and still battery light is on,. then either battery terminals are dirty or not connected properly or the battery voltage is low.Get the battery re charged to proper voltage.The exact battery voltage of charged battery is 12 volts..Re check and confirm with voltmeter. This should help.Thanks.Helpmech.

retest your alternator/charging system. Either alternator or voltage regulator is bad. If you have a volt meter/or access to one - easy test - start car and test voltage at battery - it should be 12.6 - 14.8 volts w/car running anything less you have alt/volt reg problem

11.50 volts won't be enough potential to overcome the batteries 12 volt standing charge.

Either your alternator is shot...which you can check by going to an Autozone and having a free system check. Or your battery is already going bad and not sending enough voltage to the alternator to make the 13.8-15.8 volts it should be making.

If the alternator is the culprit a good mechanic will swap it out for a fairly low price and save you a lot of headaches.

Good luck and be careful.

if u put 3 bateries on a loop u can charge them on a 24v loop

could be just a bad gauge,thak it too auto zone and have them test it while its on the truck,if it reg the same on their tester then your got a short

new altenator or junkyard one.if new return it, if junkyard just ignore light as its odds on they will not change it .the red light is caused by the difference in the voltage between input and output voltages .Quick test --start engine and run at 1500rpm disconnect battery and turn everything electrical on and if engine stops then change altenator if it stays running then altenator is OK