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Electrical - Charging Systems

With often good reason, the electrical system is one of those areas that many folks just are not comfortable with. To the inexperienced, there's a certain mystique or "How does that work" factor that generates an immediate amount of uncertainty and to make the situation a great deal more difficult, there are huge number of variations in the systems available, even from the same manufacturer and/or engine series. It's with those thoughts in mind that we will only be covering only a few of the high spots in this section.

Many of the manufacturers have a library of helpful information available online, which can be accessed using the links provided elsewhere on our web site and a lot of in-depth information can also be found by consulting a service manual provided by the engine manufacturer.


Things to Consider

Obviously the first thing you must consider is whether your existing engine or application has or requires any type of charging system output. At first thought, you might think that a "recoil starter only" type of engine would have no need for electrical output and while that is largely true, there are some applications that do still have a small charging coil incorporated into the design. One example might be on an engine designed for a go kart application that has headlights and/or tail-lights. In this case, even though it's equipped with only a recoil starter and no battery, there would be a small charging coil needed to drive the lighting system or some other accessory.

Another more common example would be on a commercial walk-behind mower that is of the "recoil only" variety, but needs a small charging coil to provide power to an electric PTO clutch. Speaking of PTO clutches, be aware that these units require a minimal charging system output of at least 9 amps.

These are some of the potential "gotcha's" that you will need to consider when selecting a new engine.


Quick Questions


Chances are pretty good that if you answer yes to any of these questions, you will need to search for an engine that has an electrical charging system that at the very least, will match the minimal power output requirements for your old engine.

As mentioned earlier, we have a lot of resources that might be helpful here at the web site and many of the manufacturers offer info as well.

  • Is the engine equipped with an electric starter?
  • Does the equipment have lights or other electrical accessories?
  • Is the PTO engaged using an electrical switch?
A/C Only Output

You will notice in the database several listings for 18 Watt charging systems. These are primarily available on "Snow/Winter" type engines, where the A/C only output is used for running lights or other accessories. Do not confuse these with the type of systems intended to charge or maintain batteries.

Additional Considerations

Okay, we'll assume that you do need an engine equipped with an electrical charging system and that you've identified the minimum output requirements. What's next?

From here, you will need to consider the types of output required for the application. For example, some systems may require AC only, DC only or some combination of the two and you will have to match those specifications. In some extreme situations where there are no other options, it is possible to convert AC to DC by installing an electrical diode inline from the AC source, but it's generally not possible to do so going the other direction.

Another consideration is whether the system needs to have a regulated or unregulated output. Typically, systems producing large output (15-20 Amp) will be of the AC variety, in which at least one circuit must be converted to DC voltage and regulated. This is usually accomplished by means of a regulator/rectifier attached to the engine. AC to DC conversion on systems designed for smaller output is usually handled by means of a diode hard-wired directly into the circuit.

However the conversions are made according to the engine design and whether or not it's a regulated circuit, charging a 12 volt battery requires output of at least 13 volts DC.

Final Considerations

To finish up our topical coverage, let's look at situations where you are changing from one engine brand to another or from one design to another from the same manufacturer. One of the first things you can anticipate at installation time is that there will be differences in the electrical connectors.

This seldom represents a "show stopping" situation and the connector can often be modified to match your needs, but you may need to have access to and be familiar with, the use of a multi-tester in some cases. Often it's easy enough to compare the circuitry from one engine to another and make the connection adjustments accordingly. You might also contact the equipment manufacturer to see if your new engine was an option for your equipment model series. If so, they may already have a harness available that will plug right in.

Whatever else you may try, do not guess at it! To do so could result in major damage to your charging system and/or electrical circuitry on your equipment. If you've purchased an engine from us and find yourself stumped with matching up the connections, give us a call and we will try to assist you as best we can.

In Summary

The absolute best case scenario is the one where you select an engine showing to have the same charging system as the one that you are replacing. If that isn't a possibility, match the system up as closely as possible, use the resources that are made available from the manufacturers and/or call us for some advice. Just proceed with caution.



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