What happens if you put a motorcycle battery backward (position)?

By Arif

Installing a motorcycle battery

Do you have a nick of playing with your motorcycle battery? If yes, I am sure you must have faced instances of misplacing or wrong positioning of the battery. So, what happens if you put a motorcycle battery in a backward position?

This is the main topic we will cover in this post. Additionally, you will also learn about the steps to take after performing this silly act and what is the correct way to place the battery on a motorcycle if you want to continue doing it yourself.

We will also answer some of the common questions related to motorcycle batteries so continue reading!

What happens if you put a motorcycle battery backward (position)?

If you put a motorcycle battery in a backward position it could potentially damage the battery and cause many other issues to your bike’s electrical system.

Some of the causes include sparks, short circuits to the main fuse (s), and a significant impact on the engine control unit.

If you don’t know how to position and install a battery on a motorcycle it is better to take help from a two-wheeler mechanic. However, if you have done this act accidentally or purposely then be ready to witness….


There will be clear sparks when the battery is positioned incorrectly. In the backward position, the battery terminals are completely reversed making it vulnerable to sparks and explosions.

The reverse order of the positive and negative terminals can create a short circuit leading to sparks. These sparks can turn into a potential fire if the metal frame and other nearby parts of the motorcycle come in contact with each other.

Damage to the electrical components

Damage to the electrical components such as the ignition system, charging system, and other electronics relying on the battery is inevitable.

This is due to the reverse order of battery terminals that also reverses the current flow resulting in damage to the entire electrical system.

Motorcycle dashboard

Short circuit to the main fuse

The main fuse of the battery is the first victim of reverse polarity. The fuse is mainly located near the battery terminals which gets burned if the battery is installed in a backward position.

Your motorcycle won’t start with the fuse damaged due to the short circuit created by the reversed position of the battery.

Impact on the ECU

In all likelihood, the engine control unit/module of a motorcycle may also get impacted due to the backward connection of the battery.

The electrical issues and short circuits are capable of damaging the whole ECU which means malfunctioning or failure of many components such as capacitors, resistors, fuel injectors, ignition timing, etc.

Battery damage

Lastly, the battery itself may not survive its structure if it is connected in reverse polarity. The internal components of a battery may get overheated releasing toxic fumes which can be dangerous to handle. In some cases, the battery may even explode.

What to do if you have put a motorcycle battery in a backward position?

If you realize the incorrect position of your motorcycle battery it is essential to take some steps immediately to avoid the above-mentioned damages.

Removal of battery – Disconnect the battery and remove it to check the signs of any damages or mal-functionality. When you do this ensure to take proper precautions like wearing gloves, etc. to protect yourself from electrical hazards.

Inspect the battery – Check the battery all around to find the signs of any damage. Look for melting, deformation, or leakage points. If there are any abnormalities found do not attempt to connect it again.

Check the fuses – Wrong connection definitely affects the fuses of a battery. Inspect the condition of fuses to see if they are blown or still working. If the fuses are blown it is necessary to use a spare one or replace them before connecting the battery.

Reconnect the battery – If the battery is found to be in normal condition you can re-attempt to install the battery with the correct polarities. Make sure to double-check the position of terminals and the connection of wires.

Test the electrical components – Start the motorcycle to test the electrical system and everything else is functioning properly. Ensure the starting sound is normal, and check the headlights, signals, and other electrical components are working correctly.

Seek professional help – If you are not sure of the process to disconnect and re-install the battery it’s best to seek professional help. If you have re-installed the battery yourself it is still recommended to get the connection confirmed by a motorcycle professional to ensure the battery and motorcycle are safe to ride again.

Steps to install the motorcycle battery correctly

If you are looking to install a motorcycle battery yourself but don’t know the correct way to do it here are the basic steps to follow:

  • First, turn off the motorcycle and locate the battery position. Generally, most batteries are placed under the motorcycle seat so remove the seat to work on the installation.
  • Once the battery is located, attempt to remove the screws with the help of the proper size wrench. Loosen the screws appropriately without letting the terminal cables touch any of the motorcycle metal parts.
  • Before displacing the battery notice the positive and negative terminal positions closely.
  • Now, remove the old battery from the tray. Inspect the condition of the tray and clean it with a wire brush or a cleaning solution. Ensure to perform cleaning on the terminals as well.
  • Next, place the new battery in the tray. Before completing the placing, ensure to check the position of the battery terminals. Look for the positive and negative signs and connect them correctly to the appropriate sides.
  • Tighten the screws and double-check all the connections. Once you are sure everything is properly placed turn on the motorcycle to confirm the battery is working properly.
  • Check the electrical system, components, and accessories are working fine, and wrap up the installation by placing the seat back.

Here is a small video to help you understand the process of installing a motorcycle battery correctly –

What happens if you use jumper cables on a reversed-position motorcycle battery?

Using jumper cables on a reversed position motorcycle battery can create a short circuit leading to larger sparks.

Related Read: Jumper cable sparks when connecting

The preceding damage from the sparks could lead to the malfunctioning of the battery, electrical system, and many other associated parts depending on the electrical flow.

In some cases, the sparks can turn into potential fire frying up the whole motorcycle.

Can you fix a battery that has reversed polarity?

Fixing a battery that has reversed polarity is possible but not recommended. Doing this could further damage the battery components and may lead to dangerous consequences for the person doing it.

Still, depending on the severity of damage and duration passed in reversed position a battery can be tried for fixation. Here are some steps you can attempt to fix a reversed polarity battery:

  • Disconnect the battery from the terminals and isolate it from the motorcycle.
  • Inspect the severity of damages such as leakages, corrosion, bulging, etc. that may decide the fate of the battery from getting fixed.
  • If you see marginal damage on a battery try charging it using a battery charger. Monitor the charging process to see if the battery is able to hold the charge. Make use of a multimeter/voltmeter to test the charging.
  • If the battery does not hold the charge even after charging in multiple attempts then it cannot be fixed. A replacement is the only option.
  • If it does hold the charge try reconnecting it to the motorcycle. As a precautionary step, take your motorcycle to a professional mechanic who can confirm the use of such a battery from a safe riding perspective.

Final thoughts

A motorcycle battery installed in a backward position is always dangerous and risky from a riding perspective.

Such position of batteries reverses the flow of current damaging the battery itself and many other parts of a motorcycle.

The effects of reversed polarity can corrupt the whole electrical system of a motorcycle making it useless to ride.

If you are not sure about installing or replacing a battery on a motorcycle it is better to get it done under professional guidance.

If you have installed the battery in reversed order accidentally then follow the information and guidelines from this post to rectify your errors and learn the process of battery installation correctly.

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I am the founder of TheCarPlus. As a passionate car owner and enthusiast, I offer practical solutions and insights from my own personal experiences combined with extensive online research.

The purpose of creating this website is to empower fellow car owners and motorcyclists like 'YOU' with knowledge and practical solutions to enhance your vehicle's performance and aesthetics.

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