Rectifier Regulator Signal Wires

Ok, guys – we’re going to get a little technical in this blog post!  We’ve had so many questions about a “missing” signal wire that we asked our tech guru Sean for an exact answer.  This is what he had to say.

Many Rick’s Motorsport Electrics Rectifier/Regulators eliminate what is commonly referred to as a “signal wire” on original equipment (OE) pieces. For example, on a 1981 Kawasaki KZ440, there are 5 wires going to the OE part: 2 yellow wires (AC inputs), white/red (DC “+” output), black/yellow (DC “-“ output), and a brown wire. The brown wire is the signal input from the battery. The Rick’s piece features only 4 wires; the position where the OE brown wire was is vacant. This is because the Rick’s part is capable of regulating through the DC wires without the sensor input.

Why is this advantageous? Because a regulator, like any electrical device, is only as good as the information you put into it, and any voltage drop between the battery and regulator on a signal wire can result in a “false positive” reading of an overcharge at the battery. To illustrate, here’s a diagram showing a full-wave Rectifier/Regulator with a signal wire operating properly:

The battery in this circuit is charging correctly. However, if corrosion, a poor contact, or any weak point occurs (this can commonly occur if the contacts in the main ignition switch have any kind of wear on them), the regulator will “mis-read” the battery and overcompensate in terms of charging voltage. Here is the same circuit with an oxidized or worn-out contact in the switch causing a .75 volt drop between battery and regulator on the signal wire:

The rectifier/Regulator appears to be over charging, however nothing is wrong with the component itself.  It is simply acting on inaccurate input.


And finally, the same circuit with no connection at all (as if the signal wire was cut):

The regulator no longer has input from the signal wire and no way to properly regulate the battery.  This results in an extreme overcharge.  The same rec/reg can produce 3 different results depending on the integrity of the signal circuit.  And THAT is why Rick’s eliminates the the external signal wire = problem prevented!