Checking your batteries voltage and charging system

New charging systems are reliable and efficient. Knowing how to check your charging system output is a basic troubleshooting tool, and a straight forward procedure.

Battery voltage without the engine running should be 12 - 13 volts.
The multimeter shows the battery has a healthy charge of 12.19v.

Checking the batteries voltage when the engine is not running should be around 12v.  This is checked across the negative and positive poles of the battery.  Using the DC (direct current) setting on a multimeter or voltmeter the black probe goes to the negative or ground, and the red probe gets placed on the positive terminal of the battery.

“Without vision, even the most focused passion is a battery without a device.”

Ken Auletta


Charging system regulator rectifier R/R Ballistic battery
Here the multimeter shows the charging system pumping out 13.56v

Checking the output voltage of the charging system is done when the bike is running.  The charging output voltage is checked the same way (across the negative and positive terminals of the battery).   Checking it at this point will tell you exactly how much voltage the battery is receiving when the charging system is running.  You will see a slight increase in voltage when the RPMs of the engine are raised, although it should never exceed your maintenance manuals specifications listed.  The input voltage  from the charging  system must be more than the voltage of the battery so the battery can take a charge.  On the same respect the amperage must be more than the amps being used by other accessories ex. headlights, stereo, add on fuel injection controller, or heated hand grips.

The charging voltage needs to be more than the battery will hold when fully charged.  Usually never more than 14.6v.  Your repair manual should have this procedure and specifications listed in the electrical system section of your maintenance manual.  Again, the above is just a rough guideline and the specifications for your bike may vary.  If you plan to implement a mosfet style Rectifier / Regulator the above is the first steps needed to be taken before moving further.


Riding motorcycles and wrenching since my preteen years, I have moved from motocross to street bikes. Being a teen back in those days it was tough to get me off of the bike. Now days even though I am very busy being a dad I still have my weekends and go to the track to race and on occasion will do a track day or two.

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