A rectifier is an important part of the electrical circuitry on modern bikes. It converts the alternating current (AC) output from an alternator into direct current (DC), so that it can be stored in the battery.
Changing AC to DC allows the charging system to function as designed, while also saving on electricity. In some ways, the rectification process is the best way to reduce the power of a high-current AC source such as an alternator.
Alternators put out a lot of power, which means that they can easily fry the wiring in a car if they’re not connected correctly. Fortunately, it’s pretty easy to protect a car’s wiring from this kind of damage.
The solution is a regulator/rectifier. These charge the battery while at the same time keeping it charged and protecting the alternator from overheating. Regulators/rectifiers aren’t perfect, but they do a good job of keeping the alternator running without letting it overheat and fry itself.
They’re also very inexpensive, which makes them a smart investment for anyone looking to improve their motorcycle’s performance and longevity. They’re also easy to diagnose if they start to fail.
To test the operation of a regulator/rectifier, you need to connect the positive and negative leads from a multimeter to each terminal on your bike’s battery. If the meter reads 12.5 to 13 volts DC, your regulator/rectifier is working properly.
If the meter reads higher than that, it’s probably a sign of a problem with the regulator/rectifier itself. The most common problem is that the polarity of the rectifier diodes is wrong, which can cause the regulator/rectifier to overcharge or undercharge the battery.
You can use a simple test to determine whether your rectifier is in good shape or not, but the most accurate way to check is to hook up your motorcycle’s stator coil. With the motor running, and the engine speed set to 5000 rpm, measure the voltages coming from each stator coil terminal. If the meter reads between 12.5 and 13.25 volts DC, the rectifier is operating correctly.
Alternatively, you can test the output of your rectifier by connecting one lead of your multimeter to each terminal on your battery and the other lead to the minus (or negative) terminal of the rectifier. If the meter reads more than 12.5 volts DC, it’s probably time to replace the rectifier.
In addition, it’s important to remember that your battery should always be charged before you start riding. This will allow the battery to be ready when you need it most, as well as helping prevent the risk of a dead or dying battery during your ride.
It’s also a good idea to put a fuse between the battery and the rectifier, especially if your bike’s wiring shares a single harness. The fuse will disconnect the rectifier from the battery if it ever shorts to the wiring, and will prevent it from frying your alternator.
Another thing to keep in mind is that if your rectifier fails, the alternator will run out of juice before it’s fully charged, which can lead to problems with the engine and the brakes. That’s why it’s a good idea to have a backup battery in case your primary one isn’t available.
