Alternator

From GreenTrust, the free encyclopedia.

VeggieGen Battery Charging

Our Generator came with an AC Delco 10si series alternator.

One large connection that is the Alternator output, known as the Bat, this connection has "Bat" cast into the housing (aftermarket housings may not incorporate these markings). Two additional tabs (inputs to the internal regulator) are used to interface the vehicles wiring harness, these have "1" and "2" cast into the housing next to them. A two terminal Molex connector is generally used to connect the wiring harness to the regulator circuit.

Here are the details on the individual terminals:

"Bat"- this terminal is for the alternator output to the battery. On some jeeps this output goes directly to the ammeter inside the cab, and returns and has a fusible link in series somewhere along the line. Later versions used a voltmeter, and this terminal went to the solenoid and on to the Pos-Terminal of the battery. "1"- this terminal (usually closest to the "Bat-terminal") is fed from the Ignition thru a lamp ("idiot light"), and is used to supply the magnetic field inside the alternator with the voltage needed to operate. When the engine is running, if the idiot light is on, the output voltage of the alternator is out of specification. Some vehicles utilized a resistor wire of 15.6 Ohms in lieu of the lamp to drop the voltage at this terminal to specified levels (this may be regulator specific).

The lamp limits the voltage to the "Field" terminal, and this current limited voltage is what tells the regulator to start/continue/stop charging. When the alternator begins to charge, the voltage increases at the battery. This increase in voltage eventually reaches a point (as the alternator charges the battery) to where it is equal to the voltage divider circuit designed into the alternators regulator. Thus they equalize out and the voltage being fed to the "1"-Terminal during normal vehicle operations the lamp only lights when there is an over-voltage or under-voltage condition.

The “idiot” light is there to act as a “visual enunciators” under voltage and over voltage conditions at the battery. Either of these conditions will energize the "idiot" light.

"2"- this terminal can be fed from the positive battery post or the starter solenoid where the positive battery post connects to the solenoid switch. This is an input to the alternator that is used to sense the battery voltage; some applications use a modified regulator circuit and may only use one or even perhaps neither of these two regulator terminals. One-wire alternators come to mind here. That is about all there is to it, in the most simplistic terms.

Alternator Theory

How to hookup the Ammeter

Ammeter Hookup

House Battery Charging

We are interested in using our alternator to charge our house batteries, but the standard auto regulator is not designed for charging deep cycle batteries. This article explains the issue well, and some solutions, but we still are looking for something better:

"Car voltage regulators will not work well in deep cycle applications. The regulator makes its decisions based only on the system’s voltage. This is fine with the average car battery which is cycled to less than 1% of its capacity before being refilled. However, the deep cycle battery is almost empty when it is recharged. The car voltage regulator attempts to instantly bring the system’s voltage to 14–15 Volts. A 12 Volt deep cycle lead-acid battery will not reach a voltage of 14 Volts until it is almost filled. The net result is that the car regulator dumps the entire output of the alternator into the batteries until they are full. This is almost always too much energy too fast for a fully discharged battery. To compound the problem, the car regulator’s voltage limit is set too low for deep cycle service. This low voltage limit means that the batteries are charged too slowly when they are almost full, resulting in many extra hours of generator operation to totally fill the battery pack. Since the car regulator is set at about 14 Volts, we are unable to raise the system voltage up to over 16 Volts for the essential equalizing charges."

From "Build Your Own 12 VDC Engine/Generator"