Will The Motorcycle Run With A Dead Battery?

For today’s automobiles, including modern motorcycles, the battery is a very critical part. The modern motorcycle depends on the battery not only for its starting but also for various other basic and advanced facilities available on it.

So, what if the battery dies? Since motorcycles are smaller than cars, people tend to think that motorcycles can be started with a dead battery.

Can you start and run your motorcycle with a dead battery? If yes, how do you do that? Will the motorcycle run with a dead battery? This article is an effort to answer these questions.

Will the motorcycle run with a dead battery?

The answer is yes. Most of the motorcycles with manual transmission can be started and run with a dead battery. However, keep in mind that the dead battery referred to in this article is a battery that is discharged due to some reasons, but is at its marginal health (still has sufficient life in it). The reason for discharge can be things like leaving your motorcycle unused for over a month and causing the battery to die or similar reasons.

Our main issue in this article is “Will the motorcycle run with a dead battery?” Let us examine this by slightly modifying the question to “Will the motorcycle start and run with a dead battery?”. The motorcycle should start first before it runs, is it not?. The different methods for starting and running the motorcycle with a dead battery are:

• Charging the battery.
• Jumpstarting the dead battery using a jumper cable and a good battery.
• Using a portable power pack (this has a jumper cable as an accessory).
• Bump starting the motorcycle.

Charging the battery

You can do this if you are at home and not in a hurry to go somewhere. Connect a charger to the battery and charge it. The battery gets charged and you can start the motorcycle in the normal way. This method works for all motorcycles.

Jumpstarting the dead battery using a jumper cable and a good battery

Jumpstart method uses the working battery of another vehicle (a car or motorcycle) and draws the power from it to start your motorcycle. For doing this, you need a jumper cable set and a Good Samaritan to help you. To do this:

• Connect the red color crocodile clamps of the jumper cable to the positive of your motorcycle’s dead battery and the positive of the battery of the other vehicle (car).
• Connect the black color clamp at one end of the jumper cable to the negative terminal of the car battery and the other black clamp to the negative terminal of the motorcycle dead battery (be careful, it will spark).
• Keep the car running to avoid draining its battery.
• Get on the motorcycle, press the starter button and the motorcycle should start.
• Take out the clamps of the jumper cable (negative black clamps first).

Keep your motorcycle running at high rpm and allow the stator to charge the battery.

This method works for all motorcycles including motorcycles with automatic transmission.

Using a portable power pack (this has a jumper cable as an accessory)

Portable power pack is a very useful gadget and it enables you to charge your smartphone, has a powerful torch for an emergency, and has a lithium-ion battery strong enough to start your motorcycle or car. This comes with a jumper cable.

Connect the jump starter cable to the power pack and connect the red (positive) and black (negative) clamps to the positive and negative terminals of the dead battery respectively. Get on the motorcycle, press the start button, and start your motorcycle. Take out the jumper cable and leave the motorcycle running to allow the stator to charge the battery.

This method works for all motorcycles including motorcycles with automatic transmission.

Bump starting the motorcycle

In the normal course, the motorcycle engine starts when you press the starter button, and it drives the rear wheel of the motorcycle through the clutch and transmission. The bump start does the reverse of this, and this means the rear wheel of the motorcycle rotates and makes the engine work.

For bump starting the motorcycle, it has to be pushed. Either you can push the motorcycle yourself by running along with it or have your friend push the motorcycle for you while you sit on it. The first method is not safe, do not try it. Let us discuss the second method.

Choose a road that is flat or has a slope (slope is better). Sit on the motorcycle, engage the gear to first or second, turn on the motorcycle, hold the clutch pressed, and request your friend to give a push. When the motorcycle gains momentum, leave the clutch, and press the starter button.

Normally, you should be able to start your motorcycle within two to five attempts. The bump start should make the rotor rotate so that the stator can generate sufficient electric power to charge the battery and the charged battery starts the motorcycle. Bump starting is normally useful for lightweight manual transmission motorcycles.

A motorcycle with an AC CDI ignition system will start even if the battery is completely dead, and you can even run the motorcycle albeit without lights. In this case, replace the battery immediately.

The bump start method may be difficult for heavy motorcycles with a manual transmission since pushing is not easy. Also, it does not work with motorcycles with automatic transmission.

The ignition system of a motorcycle

Different types of ignition systems used in motorcycles are briefly explained here to indicate the role of the battery in the ignition system.

You use an electric starter to start your motorcycle. However, the ignition or starting systems of a motorcycle are different and they are normally of three types.

• Motorcycles with an ignition system that has an AC CDI module (AC CDI-alternating current capacitor discharge ignition).
• Motorcycles with an ignition system that has a DC CDI module (DC-direct current).
• Motorcycles with electronic ignition system (also called transistorized ignition) or ECU (electronic control unit).

Motorcycles with an ignition system that has an AC CDI module

This system has the following parts:

Stator and rotor – A stator and rotor assembly (rotor is assembled on the crankshaft and rotates with it and has permanent magnets on its inside diameter. The stator has copper coils on iron cores on its periphery and the number of coils can be 8 or more. One of the coils has thick copper winding and is called an exciter coil. The stator is assembled on the crankcase cover and in the assembled condition the stator is positioned inside the bore of the rotor.). The rotor has a small protrusion on its outside diameter.

When the engine is running the permanent magnet on the bore of the rotor passes over the copper coils on the periphery of the stator. Electric current (AC) is induced in all the copper coils.

The electric current (AC) induced in the exciter coil is used for the ignition or starting system and the AC induced in the other coils is used for charging the battery.

Pick up coil (pulse generator) – This is a small unit assembled onto the crankcase cover and has a magnet at its tip. In the assembled position the tip is positioned above the outside diameter of the rotor. When the magnetic tip of the pickup coil comes over the projection on the rotor outside diameter, an electric current is induced and the pickup coil sends a pulse to the CDI.

CDI Module (capacitor discharge ignition) – CDI has a capacitor and can store and amplify the voltage of the AC current received from the exciter coil of the stator.

Ignition coil (this has a primary and secondary coil, and works like a transformer) – The ignition coil receives the high voltage power from the CDI module and multiplies its voltage (200 times) in the secondary coil, and sends it to the spark plug.

Spark plug – The spark is mounted on the cylinder head and it needs a voltage of 3000 to 5000 volts to create the spark.

The exciter coil of the stator and pick-up coil is connected to the CDI module. The CDI module is connected to the primary of the ignition coil and the secondary of the ignition coil is connected to the spark plug through a cable and connector.

Working – When you press the starter button, the starter system runs the crankshaft (rotor also rotates since it is mounted on the crankshaft), the magnets on the rotor induce an alternating current in the exciter coil and other coils, the current from the exciter coil moves into CDI, the capacitor in the CDI stores and builds up electric energy and amplifies its voltage; the pickup coil sends the pulse to the CDI, the CDI releases the high voltage electrical energy to the ignition coil, and the ignition coil multiplies and release very high voltage electrical energy to the spark plug, and the spark plug makes a spark and ignites the compressed mixture of fuel and air. All these things happen in a fraction of a second.

The motorcycle starts working and the AC generated by the other coils of the stator is sent to the battery through the rectifier controller unit, and the battery receives the direct current charge.

Motorcycles with an ignition system that has a DC CDI module

This works similar to the one with AC CDI and the differences are (i) the stator does not have an exciter coil and the complete alternating current generated by the stator is sent to the battery through the rectifier controller and is used for charging the battery and (2) the DC CDI receives the DC electric current directly from the battery.

The working is similar to the AC CDI system, and the DC CDI releases the amplified power to the ignition coil when it receives a pulse signal from the pickup coil.

Electronic ignition system

The electronic ignition system has a transistor that acts as a switch and there is an ignition coil. This uses the DC electric power from the battery to create the high voltage power required by the spark plug. In this case also the AC generated by the stator is sent to the battery (through rectified control unit) for charging it.

Frequently asked questions (FAQ)

Now, you are fairly aware of the role of a battery in your motorcycle and its importance. If you want a peaceful and trouble-free ride, it is important to take care of the battery.