How to Charge a Motorcycle Battery with a Car

There may be little worse than the feeling that hits a motorcyclist when you turn the key on your Harley Davidson or motorbike and nothing happens because its battery is dead. In a pinch, you can use your car to jump-start a dead motorcycle battery. But because your car battery is more powerful than your motorcycle battery, it's important to be careful when charging latter with the former. You jump-start your motorcycle battery in almost the same way you would charge, say, a Honda, but, because it’s a different type of battery (motorcycle charger vs. car battery charger), you won't start the car, so the process will take a period of time from 20 to 30 minutes. Motorcycle batteries have amps between 5 and 20, while car batteries are over 40. Because of this higher amperage, it’s important to prevent overcharging your bike battery.

1. Position your motorcycle so it is as close as possible to the hood of the car

To begin the charging process and fix the dead battery, position your motorcycle so it is as close as possible to the hood of the car you will be using as your jump starter, without touching. You will need to stretch your jumper cables between the two.

2. Turn off the engine for both the motorcycle and the car

Turn off the engine for both the motorcycle and the car.

3. Find the positive and negative terminals on both batteries

Find the positive and negative terminals on both batteries. You may need to clean a little corrosion off the terminals to see the markings.

4. Find the positive and negative ends of the jumper cables

Find the positive and negative ends of the jumper cables. The positive clips are usually the red ones, and the negative clips are usually the black ones.

5. Connect one of the positive clips of the jumper cable

Connect one of the positive clips of the jumper cable to the positive post of the motorcycle battery.

6. Clamp the other positive clip to the car battery

Clamp the other positive clip to the car battery. Make sure both clips have a good grip on the battery posts and aren't in danger of falling off. Do not allow the positive end of the jumper cable to touch any metal on the motorcycle.

7. Connect one of the negative clips of the jumper cable

Connect one of the negative clips of the jumper cable to the negative post of the car battery.

8. Connect the other negative clip to a sturdy piece of metal on the motorcycle

Connect the other negative clip to a sturdy piece of metal on the motorcycle, such as the frame or the rear axle nut. This will ground your circuit, which helps prevent an explosion.

9. Refrain from turning on the car

Refrain from turning on the car. Let the car battery slowly transfer power to the motorcycle battery. In a few minutes, try to start the motorcycle while it is still connected with the jumper cables. Depending on the condition of your motorcycle battery, you may need to wait 20 to 30 minutes before trying again.

10. Disconnect the jumper cables

Disconnect the jumper cables in the reverse order that you connected them once your motorcycle is running. Start with the negative clip from the motorcycle, then the negative clip from the car battery. Remove the positive clip from the car battery, then the positive clip from the motorcycle battery.

Turn off both vehicles and make sure lights and other equipment is also turned off. Open the car hood and remove any protective caps over the battery terminals on both vehicles. Leave the car turned off until you are finished jump starting the motorcycle and have disconnected the jumper cables.

Connect one red clamp to the positive terminal of the motorcycle battery. Make sure the clamp does not touch any other metal part. Connect the black clamp to the motorcycle frame (try to choose a point free of paint or chrome to avoid scratches or discoloration). It's better not to connect directly to the negative terminal as this increases the chance of damaging the battery.

Connect the other red clamp to the positive terminal of the car battery, making sure the clamp touches nothing else. Double-check that you are connecting positive to positive. Next, connect the black clamp to the negative terminal of the car battery, being careful not to touch the positive clamp in the process. Leave the car turned off.

Start the motorcycle. Unless the battery is totally gone, it should start right up. Let it run a few minutes to warm up the motorcycle engine before disconnecting the jumper cables.

Disconnect the jumper cables in the reverse of the order you connected them (Steps 2 and 3). Be careful to keep the clamps from touching anything metal until the cables are fully disconnected. Leave the motorcycle running until you drive it home or to a bike shop to get a new battery or a proper recharge.

While trickle chargers and battery tenders are ideal for maintaining battery health over time, they might not provide the necessary power for jump-starting. A car's alternator, on the other hand, can deliver a higher voltage and amperage, making it suitable for the task. If using a smart charger, it's important to set it to 2 amps for a 12-volt lead acid battery or follow the manufacturer's instructions for lithium batteries. Another option is a 10-amp, 12-volt charger, or a 5-amp charger for AGM batteries, which can help deliver a significant boost to the motorcycle's battery, allowing it to start smoothly.

Warnings

Never turn the ignition on your car while charging your motorcycle battery. Because a car battery is more powerful than a motorcycle battery, that would damage your motorcycle battery beyond repair.

Wear eye protection when jump-starting a car.

Always jump-start a vehicle in an open area free of anything that could cause an explosion, such as a cigarette or an open flame.

Video: How to Charge a Motorcycle Battery

Helpful comments on this video:

• Charger should be OFF before fitting or removing clips
• I bought a brand new bike and built it did an oil change and everything and never got a first start up and it seems like the battery was low out of the box so im gonna charge it wish me luck today