An ATV pilot would be surprised at how many different forms of electrical noise there are. Transient voltages, inductive spikes, load dumps and switching noise are just some of the noise that electrical engineers have to deal with on today’s quads. For example, any electrical coil such as the coil in a starter solenoid, will send out a nasty voltage spike when power is removed from it, Fan motors turn into generators when power is removed from them, sometimes briefly putting out as much as 30 volts DC!
One very serious cause of noise is when the battery is disconnected from the system. This is known as an “open battery” condition and the designer of an electrical system should design for and test for this commonly occurring problem. The battery acts like a giant filter capacitor on the entire electrical system. The battery provides stability to the electrical system like a flywheel does to the crankshaft of an engine. When the battery is disconnected, especially intermittently, the bus voltage suddenly wants to fluctuate up and down severely. The voltage regulator can and should be designed to keep open battery voltage fluctuations within reasonable limits so electrical parts are not damaged. In my opinion this should be a design requirement on all ATVs, however some brands do not design for this and the owner of that ATV could be in for an expensive bill if one of his battery cables breaks or works loose while in use. At the very least, electronic components such as the speedometer should be designed to turn themselves off without damage if an open battery or other over-voltage situation occurs on the electrical bus. Ask an experienced technician at your dealership how well your ATV will withstand an open battery condition and maintain your ATV accordingly.
The regulator design directly controls how much ripple the DC voltage has, but the regulator cannot minimize or “attenuate” all of the noise on the electrical bus. A lot of noise must be separately attenuated as close to the source of the noise as possible. Electrical accessories that act as simple resistors such as lights and warmers should be okay to add onto any ATV from the standpoint of clean electricity. But be wary of using electronic devices on your ATV. Do your homework and see if other people are already using such devices on the same model as you own before you experiment with anything. A rule of thumb to remember is that ATVs equipped with DC ignitions and/or Electronic Fuel Injection require cleaner voltage than those that have CDI ignitions. Because of this fact it is true that the high-end, big-bore ATVs of today generally have cleaner power than older and lower-cc models do.
The answer to this question is two-fold. First, the 1:1 gear ratio of the crankshaft to the magneto assembly makes it difficult for the magneto to keep up at idle. To design a magneto that has plenty of juice at idle adds cost that most OEMs are unwilling to bear. BRP/Can-Am has tried to correct the “break-even” RPM issue on their recent models and in my opinion, they should be commended for finally attempting to eliminate the problem with charging systems being inadequate at idle.
The second part of the answer is: Unlike car and truck owners ATV consumers have learned to accept battery maintenance. In part this is because they park their machines for months at a time and under such circumstances any wise vehicle owner would charge the battery occasionally—but this is only part of the reason. The other half of battery maintenance is the widely known fact that ATVs are not designed to charge the battery at low RPM. If ATV consumers consistently demanded a charging system that would charge their battery in all riding conditions and with high-current accessories attached, ATV OEMs would eventually buckle to the pressure. ATV riders still accept the fact that they have to pay special attention to battery charging or occasionally buy a new battery. It is possible to eliminate “Break-Even RPM”, but the question is--will consumers pay for it?
Charging systems used on ATVs come in 2 varieties—single phase and 3-phase. These terms describe how, and the timing of, output power being captured from each charging coil by the voltage regulator. If you intend to use your ATV for a lot of low-RPM, slow-speed operation a 3-phase charging system will generally have a higher charging output at low RPM levels than a single-phase charging system will. A 3-phase stator can be at a slight disadvantage in comparison to a single-phase at high RPM, but it is not usually enough to matter. There is no definite rule on which system is 100% better. Simply understand that if 2 charging systems are rated for the roughly the same watts, a 3-phase system will keep your battery charged better during low RPM running than a single-phase system will (see Figure E). On the other hand, any rider who lets their quad sit unused for more than 1 or 2 months needs to put a charger on their battery regardless of what type of charging system they have. Some manufacturers list how many phases their stator is designed to generate at, some don’t. A quick look at the regulator connection can sometimes help you see. 3-phase systems have 3 AC power wires coming into the regulator, single-phase systems have two. Japanese ATV and motorcycle manufacturers implemented 3-phase charging systems first, but now there are models in every ATV Manufacturer’s stable that have this technology. 3-phase systems cost a little more to regulate but are usually worth it.
