Are you worried that your electric bike's battery temperature is (or will get) higher than average?
And have you ever experienced your bike shutting down indefinitely and wondered what could be the reason?
Such problems are common with motorized vehicles, including electric bikes.
Batteries do generate heat when they are in use. Continuous operation of these batteries can make them feel hot, and the bike shuts down when its temperatures exceed a specific limit. This problem is called overheating.
The battery is one of the essential elements of an electric bike. Its worth is about one-third of the entire bicycle's value. So, if you want to enjoy extra miles, you must invest in a good battery to provide enough power to the motor without overheating.
However, upgrading to another battery is not always a practical solution for many. You can still go that extra mile as long as your battery is in good condition and has no overheating problem.
But when the battery overheats, how will you manage it?
Keep reading. This article answers it all！
What Causes an Ebike Battery to Overheat?
Nowadays, most electric bikes have a battery monitoring system (BMS) that uses a lithium battery.
Lithium-ion batteries have been around since 1912. But since the last decade, these batteries have been regarded as more efficient and produce more power output. That explains the diversity in their applications, which extends to most power electronics like electric bikes, cars, and smartphones.
Despite these advantages, external factors like temperature, terrain, weight load, and wind speed can impact the performance of lithium batteries. Therefore, it’s natural for them to heat up as they work.
This heat wears down your battery, reducing its performance. And when it loses its efficiency, it will use more of its stored energy to power the bike for the same distance, leading to further overheating.
Most people also find it convenient to store their bike’s battery in a bag at the centre of their bicycle frame or in panniers on either side of the rear wheel. Some even build big custom plastic or wooden boxes for their batteries.
Yes, these storage solutions are good at what they do. However, they are also good insulators. They trap heat inside the battery but limit air circulation to conduct this heat away. If you go for long rides, the batteries stored in such a manner will end up overheating.
How bad can the Effects of an Overheating Battery Be?
Lithium batteries contain two electrodes and an electrolyte fluid between them through which charge-balancing positive ions can flow.
This electrolyte is usually highly combustible. But it can only be dangerous if the battery is damaged or overheated.
When one battery cell overheats, adjacent cells also overheat, resulting in a chain reaction called thermal runaway, which is difficult to stop once it has started. As a result, heat and pressure accumulate, and the battery explodes when they become too much to be sustained.
Prolonged overheating of your electric bike can cause irreversible damage to your battery, i.e., premature capacity loss. You will gradually decline the distance your bike can travel from a full battery charge.
Consequently, the battery has to use more of its stored energy for the same distance, causing further overheating.
This vicious cycle limits the battery's efficiency, which cuts into your electric bike’s range.
How Best Can You Keep an Ebike Battery From Overheating?
The short answer is cooling.
What about the long one?
Let’s get right into it!
The easiest method to keep your bike’s battery from overheating while operating is using passive air cooling, i.e., allowing air to constantly run over the battery when it's running to help cool it down.
What if you want to secure your battery in a bag but simultaneously want air to flow freely?
There is a better option for the bag fabric!
An aluminium hard case battery pack is a good conductor. It has air that will also heat up as the battery heats up. On the bright side, the aluminium case will allow this hot air to be transferred outside via convection.
Mounting this aluminium hard case battery pack directly to the bikes’ frame or rack will expose them to the air flowing over them, making passive air cooling possible.
If you prefer setting your bike's battery in panniers, use metal cage panniers in preference to bags. They will not only support your battery rigidly. They will also allow free and easy air circulation, cooling down your battery.
What if you don’t have the money/zeal for an aluminium hard case battery pack or the metal cage panniers?
You can try poking some vent holes around the nonstructural areas of the storage bag. For custom-made battery boxes, drill some holes in the front and at the back. Doing so will improve airflow, getting the much-needed cooling to the battery.
Are there Other Alternatives?
You can also restrain the battery of your electric bike from overheating by：
Avoiding Flat Tires
Batteries use less energy when the bike tires are maintained at their maximum air pressure rating.
Flat tires put additional pressure on the electric bike, meaning it will need more power to attain its desired speed.
You already know the repercussion!
The battery will drain faster than it should, leading to overheating.
Therefore, before starting your ride, it will help if you double-check the condition of your bike's tires. Ensure they're filled up to the correct pressure level and not flattened.
Avoiding Overloading Your Electric Bike
Every electric bike has a motor whose power can propel a particular load (the weight of the rider and bike itself) on flat ground until the battery is depleted.
However, flat tires may happen when you overload the bike or ride it in steeper hilly areas requiring more effort than the motor can provide. So, you risk overheating the battery and damaging the motor and its insulation, among other bike components.
Using Pedal-Assist Mode
Electric bikes come with three riding modes. Please use the pedal assist mode to avoid overheating your battery through the continuous operation. This way, you'll be helping the motor do its work; hence less power is drained from the battery.
Your Ebike’s Efficiency Starts With You!The efficiency of an electric bike battery depends on how you manage its temperature. Keeping your battery cool will help you get the most out of your electric bike’s range.
Therefore, always keep air flowing over the battery to keep it cool and ensure less pressure is exerted on tires to avoid flat tires. Also, put a little effort into pedalling to avoid overworking your battery.