Battery Charging System, Battery not charging Options

[Schmaz356]

I am building a 914-6 and I have an issue where the battery does not charge. Basically everything is new on the car (alternator, voltage regulator, battery & cables). The car runs fine but just will not charge the battery. I have checked the grounds on the body and at the transmission. The belt seems fine and is new. I pulled the battery and the regulator and brought it to a shop where they said it was putting out 14.2V using my regulator.
My Alternator wires are as follows;
Red from B+ to Starter
Black from DF to DF on the Regulator
Brown from D- to D- on Regulator
Blue from D+ to D+ on Regulator and then to the Dash Battery Light. (which is on all of the time)
Ground from D- to engine case.
When I put the system back together, I checked the continuity of each cable to assure myself it wasn't just a pulled connector or broken wire. When the car is running and reved to 2,000 RPM I still only get battery voltage.

Please help with any thoughts on what I should check next. Thanks.

[davep]

The alternator light in the instrument CANNOT be an LED; filament bulb as original only. LED will not allow charging system to work!

[StarBear]

The alternator light in the instrument CANNOT be an LED; filament bulb as original only. LED will not allow charging system to work!

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[ClayPerrine]

The alternator light in the instrument CANNOT be an LED; filament bulb as original only. LED will not allow charging system to work!

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This is how it works:

There is a circuit in the alternator to control the charging system warning lamp that is on the dash. Part of that circuit is a set of diodes mounted inside the alternator called the diode trio. The diode trio takes current coming from the three stator windings and passes a small amount through three diodes so that only the positive voltage comes through. After the diodes, the wires are joined into one wire and sent out of the alternator over the blue wire. It then goes to one side of the dash warning lamp that is used to tell you when there is a problem with the charging system. The other side of the lamp is connected to the run side of the ignition switch. If both sides of the warning lamp have equal positive voltage, the lamp will not light. Remove voltage from one side and the lamp comes on to let you know there is a problem.


On a 914, the bulb must be an original 12 volt, 4watt incandescent bulb. An LED won't work due to the way the circuit is built.

Put an old light bulb back in the lamp and I will bet your alternator starts working again.

[Spoke]

On a 914, the bulb must be an original 12 volt, 4watt incandescent bulb. An LED won't work due to the way the circuit is built.

@ClayPerrine

I recall some threads on Pelican where there was a resistor added in parallel with the bulb because the bulb current wasn't enough for the alternator to bootstrap itself and turn on. I don't think it was all years 911's.

[ClayPerrine]

On a 914, the bulb must be an original 12 volt, 4watt incandescent bulb. An LED won't work due to the way the circuit is built.

@ClayPerrine

I recall some threads on Pelican where there was a resistor added in parallel with the bulb because the bulb current wasn't enough for the alternator to bootstrap itself and turn on. I don't think it was all years 911's.

I remember that too. But I don't remember what year 911 it was.