How To Fix An Electric Bike With Intermittent Power

As the owner of an electric bike, few things are more frustrating than dealing with battery problems.

Usually, the problem is relatively straightforward: the battery works and you can go about riding your e-bike all day, or the battery doesn’t provide any power at all.

But have you ever wondered how to fix an electric bike with intermittent power?

When you’re experiencing intermittent power with your electric bike, the solution will depend on the root cause. You could be facing a problem with the battery management system, speed sensor, controller, or brake motor inhibitor. Sometimes, the only component that could be faulty is the battery prongs.

In this article, we’re going to walk you through all of the possible reasons why your electric bike is experiencing an intermittent supply of power. We’ll look at each possibility, help you understand why the problem happens and what you can do to solve it.

Let’s get started!

Main On Mountain With His Bike In Alps

Battery Management System (BMS)

All electric bikes have a battery management system (or ‘BMS’). The BMS is a small component in the form of a circuit board with electronic components on it.

As the name suggests, that component helps manage the battery’s activities, such as the inflow of power when charging and the outflow when you’re using the bike.

Simply put, the BMS protects the battery from damage and also helps to lengthen its lifespan.

How The Battery Management System Causes Intermittent Power

Remember: One of the BMS’s primary purposes is to protect the battery from damage and help lengthen its lifespan. So, if your bike is experiencing intermittent power, that could be a sign that the BMS is doing its job.

For example, the e-bike battery might be draining at a dangerously high rate. To prevent that from happening, the BMS might be cutting off power and trying to slow down that drain.

It’s also possible that the BMS is cutting off power intermittently to ensure that the battery doesn’t overheat.

In this case, the BMS is doing precisely what it was designed to do, and the intermittent power supply is a symptom of a much bigger problem.

Typically, it could be that the battery itself is in bad shape which is what’s forcing the BMS into action this way.

How To Resolve This Problem

Here, the root cause is either a failed battery or a faulty battery management system. Both of them will need to be tested and whichever one is the culprit will need to be replaced entirely.

Testing the battery with a multimeter or in another bike should give you a clear answer as to which part needs to be replaced.

Speed Sensor Failure

Electric bicycles also come equipped with a speed sensor. Its purpose is quite straightforward: when it detects that your bicycle is going above a certain speed, it will cut off the power supply.

On the other hand, if it senses that the bike is going too slow, it’ll supply the bike with power to help you speed up.

How The Sensor Causes Intermittent Power

A problematic speed sensor can cause all sorts of problems. In this case, however, it might be mistakenly sensing that the bike is going faster than it really is.

As a result, it cuts off the power supply intermittently, even when you need it to move the bike forward.

How To Resolve This Problem

A component like a speed sensor is usually much easier to replace entirely. Trying to fix it might not be worth the time or the effort. Plus, you don’t want to risk it failing again.

So, buy a new speed sensor and use it to replace the old one.

Problematic Controller

All electrical devices have a controller, and your electric bike is no different. The controller is the ‘brains’ of the operation. It coordinates all the other components that make the e-bike work correctly.

How The Controller Causes Intermittent Power

Remember: the controller coordinates the functions of all of the e-bike’s components. That also means sending power to wherever it needs to be.

So, if there’s a problem with the controller itself, it might not be able to consistently send power to the bike when it’s needed.

How To Resolve This Problem

There are some clear telltale signs that you can look out for to know if the controller is the problem. Touch, smell and look at the controller closely, and you’ll pick up on some of those signs.

For example, you might notice that the controller is overheating for no apparent reason. 

Move a little closer and take a sniff, as you might be able to pick up on burnt smells coming from inside; another indicator that the controller is damaged.

Lastly, you can also do a visual inspection on the controller and discover that some parts might be burnt.

Once you’ve narrowed the problem down and confirmed that it is indeed the controller’s fault, then that’s the part that you’ll need to replace.

Loose Battery Prongs

An electrical device is only as good as its connectors. When it comes to electric bikes and their batteries, it’s also worth checking the battery prongs and ensuring that they’re in good working order.

How Battery Prongs Cause Intermittent Power

Think of it this way: the battery prongs are the exact points where electrical power is transferred from the battery to the bike.

To make sure that the process goes smoothly, those prongs must be aligned correctly, and there must be nothing getting in their way.

If your bike is experiencing intermittent power, it could be that the prongs are misaligned or dirty. Or, it could be as simple as the prongs not being pushed all the way into the battery itself.

Any of those issues could cause your bike to lose power, especially if you’re riding on a bumpy bike path.

How To Resolve This Problem

Remove the battery and take a close look at the battery prongs. Make sure that they’re clean and free from any dust or debris. Then, check that they’re not loose or shaky and that they’re aligned correctly.

When you put the battery back in place, make sure that the prongs go all the way in and that it firmly stays in place.

Brake Motor Inhibitor

Electric bikes also come with a brake motor inhibitor. To clarify what that name means, it’s a motor inhibitor (i.e. it stops the motor) that is activated when you apply the brakes on the bike. 

By preventing the motor from running while the brakes are on, that feature helps to prevent any damage to the motor.

How The Brake Motor Inhibitor Causes Intermittent Power

The brake motor inhibitor might be mistakenly sensing that the brakes are being applied. Whenever that happens, it’ll cut off power to the motor, which you will experience as an intermittent loss of power.

How To Resolve This Problem

The brake motor inhibitor has sensors to detect whether or not the brakes are being applied. Those are the parts of the component which may be faulty and need replacing.

Final Thoughts

As you can see, there are several reasons why an electric bike may experience a problem with intermittent power.

Seeing as how this deals with the bike’s electrical system, you’ll only want to fix it yourself if you have the necessary skills and experience.

If you feel unsure about anything at all, it’s always safer to let an expert handle it for you.