Can You Overcharge An E-Bike Battery?

Electrical bicycles will come equipped with a small motor which makes it easier for you to pedal up hills and around town. The motor is powered by a rechargeable battery that needs to be plugged into a charger and charged before they can be used to power the e-bike motor.

Although charging the battery is simple enough, a lot of people worry about what may happen if they overcharge the battery.

Electric bike batteries should not be overcharged. If you overcharge them, it can shorten the battery’s lifespan and can cause it to overheat. Overtime, this may eventually make the e-bikes unusable.

Fortunately, the majority of modern ebike batteries are built with a smart charging function that will stop them from overcharging. 

Over the course of this article, the concept of overcharging ebike batteries will be discussed in more detail. This will include looking over how and why overcharging is a bad idea and how long you can safely leave a battery plugged in. 

How Would You Overcharge A Battery?

Ebikes most commonly come equipped with a lithium-ion or a lithium-ion polymer battery, but some also have a lead-acid battery. However, some also have a lead-acid battery, a nickel-cadmium battery or a nickel-metal hydride battery.

All these battery types must be charged before and between uses.

To charge any rechargeable battery, plug it into a charging device. One will come with your e-bike. If you left the battery plugged in past 100%, this would cause it to overcharge.

The majority of modern batteries can’t be overcharged as they are designed to cycle off and stop charging once they reach full capacity.

Despite this, the energy in a battery will slowly discharge on its own, even if it is not being used. If you leave your battery on the charger, it will resume charging once the stored energy drops below a certain threshold.

If you consistently leave your battery on the charger past 100%, this on-again-off-again cycle may eventually serve to lower the battery’s overall energy capacity. 

These are a couple of easy options to fix the habit of leaving your battery in the charger for too long.

  1. Obtain a smart plug or smart power bar. These will allow you to control the plug with your phone or app, to turn the power on/off or to set a timer to turn off the power after a certain time charging. 
  2. If you understand how long it takes for your battery to charge fully, you could get a simpler device such as a plug timer. You just need to set the time for charge and the amount of time your battery will sit with an active charge will be just enough.
  3. A simpler solution, if you can remember, is to set a reminder on our phone each time you change your battery.

What Effect Does Overcharging Have On Ebike Batteries?

If you often forget to take your battery off charge, rest assured that you are probably not doing any severe damage. Although overcharging is not ideal, modern batteries are built to withstand it: you are not going to cause it to overheat and melt or even explode, as you might fear.

Battery Lifespan

The actual lifespan of an ebike battery depends on what type of battery it is, the size, how often it is used and how the battery is cared for. 

Battery life spans are often referred to in terms of charge cycles. One charge cycle means the battery has used an amount of energy equal to 100%of its overall capacity. If you use 60% one day, fully recharge the battery and then proceed to use 40% the next day, this is considered one full charge cycle. 

Therefore, the lifespan of a battery is the amount of charge cycles the manufacturer estimates a battery can go through before it starts becoming noticeably less efficient.

The most noticeable effect of consistently overcharging your e-bike’s battery is on the battery’s lifespan. As the charger cycles on and off repeatedly, this will ultimately affect the battery’s overall energy capacity.

The time in which a fully charged battery will last, will gradually decrease over time regardless of your charging habits. However, overcharging will cause this to happen more quickly. 

Other Risks

When it comes to charging batteries, many people worry that there are physical dangers if you overcharge them. People claim that batteries can melt and even explode. Is there really any truth to these stories? 

Realistically, no. All modern ebike batteries are fitted with smart charging systems that will prevent it from overcharging. This will stop charging on the ebike at full capacity and when the battery reaches a certain temperature.

Even if a battery begins to overheat, it is unlikely that it will get hot enough to melt, explode or cause any sort of damage as the charger will automatically shut down.

Although there is no real risk of physical damage, it is important to remember that persistent overcharging will reduce the lifespan of the battery.

Are There Ever Advantages To Overcharging The Battery

It is widely recommended that you should not purposely overcharge an ebike battery for any reason. Any advantages that you think may come from overcharging such as added power or distance will be outweighed by the risks of overheating.

Final Thoughts

To summarise, consistently keeping your battery sat on charge for long periods of time isn’t great, but it isn’t dangerous. Modern batteries are designed to be able to withstand typical charging scenarios that people have so you will not be causing it to overheat. 

Just remember to keep the battery off the charger for long periods of time or cut the power to the charger to make things easy.