The CBX charging system does not charge at idle. At idle the battery discharges. But it does not matter. It is the nature of the powersports world’s electromagnet-based alternators to have very little power at an engine’s idle rpm. They are actually working very well at idle, but they absorb power to make electromagnetism and at an idle the cumulative electrical load exceeds the output. But get off idle and things really get going. The output curve is strong and steep, and climbs to a level that is higher than the permanent magnet-based alternators of the day. There is just no way you can say the CBX's 350 watts is low power unless your riding looks like radios and GPS and travel trailers and all manner of heated clothing. The CBX alternator wasn’t designed to accommodate those kinds of loads.

Here's how it works. Key on, engine not yet running--current travels from the battery through the keyswitch and on to the brushes, and ultimately into the electromagnet (“rotor”, “field coil”). Out of the electromagnet, the same current passes through the voltage regulator, which grounds the electromagnet so it can create magnetism. This is a DC circuit. The regulator controls the magnet by modifying the strength of the magnet’s ground. Best ground, highest magnetism--weakest ground, least magnetism. The magnetism in turn determines alternator output. At engine startup the magnet strength is maximized by the regulator, but despite this, the engine’s low rpm keeps the system from overcoming its loads and charging the battery. Unlike a car alternator, the CBX alternator does not benefit from being ratioed-up by pulley size differences. At about 1300 rpm however, the high magnetism combined with now sufficient rpm result in charge to the battery. After a bit, when the regulator senses the battery has reached 14.7 volts, it begins, in steps, reducing the magnet’s ground strength, which reduces charge, so the system will not over-charge.

Note that the system is a two-way street. It has an input side and an output side. The electromagnet requires current from the battery, and the system moves current into the battery. Note also that the keyswitch is a vital part of the charging system. If it begins to have conducting failures--which the CBX keyswitch eventually does--it will send less current to the electromagnet, which will reduce its magnetism and lower the system’s charge output. Thus the keyswitch is an integral part of the CBX charging system.

Part 3