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Avoid surprise disasters by load testing your battery

Added April 19, 2017
load test for motorcycle battery

Motorcycle batteries are the unsung heroes of riding. Each time we ride our motorcycles, the last part of our pre-ride drill is always the same—insert key and push the starter button.

It’s our trusty batteries that deliver the rumble of life to our motors. No battery power means no ride. For a modern motorcycle, it’s just that simple. So how can we avoid that terrible ride-stopping surprise? Load test your battery as part of your routine preventive maintenance schedule.

Battery testing safety and basics

Batteries contain acid and can produce very flammable hydrogen gas. Before performing any tests or services on your motorcycle battery, follow these safety precautions:

  • Know your motorcycle—review your owner or service manual first
  • Keep open flames or sources of sparks away from the battery—this includes no smoking
  • Work in a well-ventilated area
  • Wear eye protection
  • Wear rubber or latex gloves
  • Inspect the battery for leaks, cracks, or corroded terminals

Testing the battery

There’s a little preparation involved when testing a battery. You’ll need the following materials:

  • Hand tools to remove saddle or side covers to access the battery
  • Safety glasses
  • Gloves
  • A digital voltmeter with DC scale capable of showing tenths of a volt

Start with a static test

Before load testing, you should perform a static test to confirm the battery has a full charge. Use a charger, or simply take a ride, allowing the charging system to do its job. You’ll need to allow the battery to rest for at least one hour before testing. Perform this test with the motorcycle turned off.

To see how well your battery is performing, follow these steps:

  1. Set voltmeter to DC scale (range for 0–24, or equivalent)
  2. Attach positive meter lead to positive battery terminal
  3. Attach negative meter lead to negative battery terminal
  4. Read and record voltage

A fully charged battery should read approximately 12.6VDC. If it reads at or below 12VDC, recharge the battery. Allow battery to rest and test again. A battery that has been fully charged, rested, and tests between 12 and 12.6VDC might start the motorcycle, but it’s not holding a full charge.

How to load test

Load testing is reading the voltage at the battery terminal when the motorcycle is turned on and drawing power from the battery. The moment of maximum demand on a battery is at startup.

Follow these steps when using a battery load tester:

  1. Work outside or in a well-ventilated area
  2. Make sure transmission is in neutral and the motorcycle is in a stable position
  3. Securely place the voltmeter where you can read it while starting the motorcycle
  4. Set voltmeter to DC scale (range for 0–24 or equivalent)
  5. Attach positive meter lead to positive battery terminal
  6. Attach negative meter lead to negative battery terminal
  7. Read voltage while starting motor and record results

The voltage will drop at startup before the charging system kicks in. If the voltage drops below 9.5VDC, your battery has a very low charge capacity. Replace it now before it leaves you stranded.

Doing these simple steps can save you a lot of headaches. Make it part of your new riding season checklist.

Till next time, ride safe!