Does your motorcycle struggle to start? It could be due to:

  • A faulty starter motor
  • Bad wiring or connections
  • A lack of fuel
  • A clogged air filter
  • A faulty kill switch or ignition switch

Most likely, though, you have a dying battery.

Motorcycle batteries last between 2 and 5 years. Exposure to extreme temperatures, poor maintenance, and frequent deep discharges (if you haven’t been riding enough) can shorten that already brief life.

Fortunately, replacing an old motorcycle battery is an easy DIY task for anyone with a wrench.

Understanding Different Types of Motorcycle Batteries

Before purchasing a new battery, know what type your motorcycle requires.

  • Flooded Lead-Acid Batteries: Typically the most affordable option due to their simple design and materials. They require regular maintenance.
  • AGM (Absorbed Glass Mat) Batteries: These are more expensive than flooded lead-acid batteries due to their improved design, maintenance-free operation, and better performance in cold weather.
  • Gel batteries cost a little more than AGM batteries. They’re maintenance-free, long-lasting, and designed for deep discharge but have slower recharge rates.
  • Lithium-ion batteries are the most expensive option. They offer superior performance, longer life, faster recharge times, and lighter weight and are often used for high-end applications.

Signs of Battery Failure

It’s better to replace a battery too early than too late (unless you’re okay with breaking down in the middle of nowhere).

Symptoms of imminent failure include:

  • Slow engine crank when the engine takes longer than usual to turn over during a start.
  • Dimming headlights, power fluctuations in the dashboard lights, or unresponsive electronics.
  • The battery warning light comes on.
  • A swollen or misshapen battery case suggests internal damage.
  • A rotten egg smell can indicate a leaking battery.
  • A battery approaching its expected lifespan of 2 to 5 years is more prone to failure.
  • Corrosion on the battery terminals.

Testing the Old Battery

Tools Needed

  • Multimeter
  • Wrench
  • Safety glasses and gloves

Steps

  1. Park your motorcycle on a level surface with the engine off. Disconnect the old battery.
  2. Set your multimeter to the DC voltage setting.
  3. Connect the multimeter’s red (positive) lead to the battery’s positive terminal and the black (negative) lead to the negative terminal.
  4. Check the voltage reading on the multimeter. A healthy, fully charged battery should read between 12.6 and 12.8 volts. A reading below 12.4 volts indicates a partially discharged battery. A reading below 12.0 volts suggests the battery is weak and may need replacement.
  5. Inspect the battery for any physical damage, such as cracks, bulging, or corrosion on the terminals.
  6. If testing confirms the battery is weak or failing, it’s time for a new one.

Removing the Old Battery

Tools Needed

  • Wrench
  • Battery terminal cleaner brush
  • Safety glasses and gloves

Steps

  1. Park your motorcycle on a level surface with the engine off.
  2. Identify the battery location, usually under the seat, behind a side panel, or near the engine.
  3. Disconnect any accessories connected to the battery (e.g., alarm system).
  4. Put on safety glasses and gloves before proceeding.
  5. Remove the negative cable from its post, marked with “NEG” or “-.”
  6. Repeat for the positive cable (marked with “POS” or “+”).
  7. Remove any bracket holding down the battery.
  8. Carefully lift out the old battery; they’re heavy and can spill acid if tipped over.

Installing a New Battery

Tools Needed

  • Wrench
  • Wire brush or sandpaper
  • Battery terminal cleaner spray
  • Safety glasses and gloves

Steps

  1. Use a wire brush or sandpaper to remove corrosion on the cable ends. If the corrosion is severe, you may need to replace the cables.
  2. Spray battery terminal cleaner on the cable ends and terminals and scrub them with a battery terminal cleaner brush.
  3. Rinse off any residue with water and dry thoroughly before proceeding.
  4. Place the new battery in its tray (ensure it has the correct orientation).
  5. Connect and secure the positive cable first, followed by the negative cable.
  6. Reconnect any accessories that you disconnected earlier.
  7. Turn on your motorcycle to see if everything is working correctly.

Tips for Maintaining Your New Battery

  • Regularly clean the terminals with a wire brush and terminal cleaner spray to keep your battery tidy and corrosion-free.
  • Check the water levels in your battery (if it’s unsealed) every 3 months and refill it with distilled water if needed.
  • Avoid frequent deep discharges. Ride your motorcycle often, or use a maintenance charger when it sits for extended periods.
  • Protect your battery from extreme temperatures.
  • Consider investing in a smart charger to monitor and maintain your battery’s health.

Additional Tips

  • Choose a battery with higher cold cranking amps (CCA) and reserve capacity (RC) for better performance.
  • Always replace your battery with the same type and size the manufacturer recommends.
  • Consult a professional mechanic if you’re unsure about replacing your motorcycle battery DIY.

Frequently Asked Questions

Q: Can I leave my motorcycle battery on a trickle charger?

Yes, but follow the manufacturer’s instructions and disconnect it when unused.

Q: Do I need special tools to replace a motorcycle battery?

Basic hand tools like wrenches and screwdrivers are usually all that’s needed. However, a multimeter can come in handy for testing the old battery.

Q: How often should I check my motorcycle battery?

We advise checking your motorcycle battery once every three months, especially before long rides or changes in weather.

Q: What should I do if my motorcycle battery is dead?

If your battery is dead, you can attempt to jump-start your motorcycle with jumper cables and another vehicle’s battery.

Q: Is it safe to jump-start from a car?

We don’t recommend this due to the differences in electrical systems and the potential risks. A car’s battery’s current output and size can be significantly greater than a motorcycle’s.

If you must jump-start a motorcycle from a car, turn off both vehicles and use jumper cables cautiously.

Q: Can I use a car battery for my motorcycle?

Motorcycles have specific power requirements and dimensions, so using an incorrect battery could cause electrical or physical damage.

Q: What’s the best way to dispose of an old battery?

Take your old battery to a recycling center or an automotive retailer that offers battery disposal services.

Q: How can I tell if my motorcycle battery is charging correctly?

Measure the voltage while the motorcycle is running. A reading between 13.5 and 14.5 volts indicates the charging system is functioning correctly.

Q: What can cause a motorcycle battery to fail prematurely?

Several factors can cause premature battery failure, including extreme temperatures, frequent short trips resulting in insufficient charge, prolonged inactivity, and a faulty charging system.