Ask The Editors: Why Don’t ATVs Have Alternators?
Dear ATVC:
I have a question nobody seems able to answer- why do ATVs use magnetos instead of alternators like a car?
Great question! The actual reason is pretty technical but we’ll do our best to summarize here and then point you to a link where you can find a much more in-depth explanation.
ATVs, like most small engine machines, have very tight space confides to adhere to. Automotive-style alternators are usually belt driven and require quite a bit of space as well as cooling accommodations to function. Additionally, since magnetos/ stators are integrated within the engine cases, protection from the elements is a very beneficial side-effect when dealing with vehicles that get as wet, wild and mudded as an ATV.
Interestingly, magnetos were really the only option for early ATVs that had lighting but lacked batteries entirely. These early systems relied entirely upon engine RPM to spin magnets on the flywheel next to tight coils of wire we call a stator to create a charge. The electricity then passed through a voltage regulator and then directly to the lights.. Which is why revving the engine made the bulbs immediately shine brighter in response.
ATVs have gotten much more complex since the early days and thus so have their electrical demands. However, even modern machines with digital ignitions, batteries in need of charging, electrically taxing accessories and power outlets, maintain the proven tradition of running a magneto and stator coil.
If this subject interests you, a more thorough explanation can be found in this archived article by Gary L. Gustafson.
