E-Bike Battery Discharging

What is e-bike battery discharge?

When all the available battery capacity has been exhausted, the battery is completely discharged. In other words, it’s totally empty and has no power left. Running a battery completely down to deep discharge can actually damage the cells within the battery, and reduce the battery’s ability to properly hold a charge. 

To find out whether deep discharge damage has already occurred, you can test the voltage and capacity of your e-bike battery with a measuring device or take it to one of our e-bike shops for a specialist to check.

A reduction in battery capacity, of course, means that you’ll get less distance out of your e-bike per charge, but it can also contribute to the degradation of the battery components over time. 

As the components wear down, the cost of repair or replacement goes up, and it can also increase the risk of fire or overheating. The damage caused by deep discharge usually can’t be repaired, and the best option will be to take your battery to a specialist. Attempting to charge a damaged battery can cause chemical reactions that can cause a fire or explosion.

What causes e-bike battery discharge?

The most obvious reason you might see battery capacity decreasing is through long-term use. The more you use your e-bike battery and pedal assist, the more energy you’ll use up. That’s why it’s really important to properly charge your battery after every ride.

Deep discharge can also occur as the battery ages and gradually breaks down. A defective charger, or one not provided by your bike’s manufacturer, can also damage the battery.

However, the battery can run down even when it’s not in use. So even if you’re planning on keeping your e-bike in storage, you’ll need to keep an eye on the battery and maintain a charge level of around 30-60%.

Temperature and storage conditions can also affect battery discharging. Rapid fluctuations between hot and cold temperatures can impact the cells since rechargeable batteries are particularly sensitive to temperature.

High temperatures damage the liquid battery electrolytes, which can lead to a sudden loss of power. In extreme cold, an e-bike battery won’t charge efficiently, meaning it will discharge more quickly. Rapid fluctuations between hot and cold can also result in condensation forming inside the battery, further damaging battery cells.

So, it’s important to take care not to store your e-bike battery in excessively hot or freezing temperatures. It should be stored indoors, preferably in a cool, dry, and dark place. A well-ventilated storage room or garage is ideal.

What to do if your e-bike battery has deep discharge

It’s not all doom and gloom; if your e-bike battery accidentally becomes almost completely discharged (for example, after a particularly long ride or if you forget to connect the charger), it doesn’t necessarily mean your battery is no longer usable. Deep discharge is significant damage to the battery, and proper maintenance and regular charging can help prevent it.

If the cell material or BMS (battery management system) of your battery is damaged, the cells may be able to be replaced entirely in order to save your battery. This is referred to as battery recelling or reconditioning. The old cell block is simply replaced with a new one, making your battery as good as new again. Reconditioning should always be carried out by a professional. Always check with the manufacturer or an e-bike specialist for the best option. 

Of course, you could always just buy a replacement battery, but this is usually more expensive than reselling. If you have to buy a new battery, you’ll need to get exactly the same type of battery as before. The replacement battery should be mounted in the same position on the e-bike. It should also match the bike’s drive system.

Ready to replace your old set of wheels for an efficient new e-bike? Browse our range of electric bikes, and find out more on our Electric Bike Knowledge Hub.