Electric unicycles (EUC) are a fantastic way to get around town, but you should be aware of lithium battery safety. Over the last few months, there have been reports of electric unicycle lithium batteries spontaneously combusting under normal use. This is an alarming trend that can lead to serious injuries and even death if not addressed properly.
Some EUC users report having their batteries overheat for no apparent reason while others have experienced a sudden burst into flames during charging or riding them under high-demand situations, e.g., high torque, quick acceleration, and steep hill climbing. It’s important to know of the risks and variables that make an electric unicycles prone to this problem, so you’re not risking your life with faulty parts or user-error.
In this article, I share information I found about the safety of lithium batteries in electric unicycles and ways you can help reduce the risk of a lithium battery fire.
Summary (TL;DR):
- The lithium battery technology in your modern electric unicycle is safe and has a very low risk of starting a fire when you take proper precautions
- Some electric unicycle brands have a better reputation for safe battery and associated componentry quality, as well as thoughtful electrical design aimed at protecting user safety
- The key to reducing the likelihood of a lithium battery fire is by practicing safe charging, storage, and riding habits with your electric unicycle
- Follow the tips below for safer electric unicycle riding, storage, and peace of mind
What is a lithium battery?
Lithium batteries are a common power source, and you can find them in all sorts of devices including phones and tablets. Lithium ion batteries are the most popular kind of lithium battery, although you might also find some lithium polymer batteries in your device. While they have a high charge density and low weight, they can easily overheat for one reason or another-usually due to faulty parts, user-error, or a combination of both.
A quick note that a lithium battery (or lithium polymer battery) is not the same as a Li-Ion battery. Lithium ion batteries are a perfect size for portable devices such as iPods, laptops and cell phones. These powerful little gems can also be formed into many shapes which makes them highly versatile in any number of gadgets from doorbells to flashlights! With rechargeability and a long battery life, they have become an increasingly popular choice for consumer electronics.
In contrast, lithium batteries cannot be recharged and only have a single charge per lifetime. Due to their longevity and power, lithium batteries have become the battery of choice for artificial pacemakers, for example. The lithium battery are also good candidates as sources of power on devices that are out of reach, such as smoke detectors or computer motherboards.
To keep things simple in all discussions about electric unicycles, we will refer to the rechargeable li-ion battery interchangeably with the term “lithium battery”.
It’s important to take precautions and prevent lithium battery fires in your e-unicycle. This is especially true as the popularity of these electric mobility devices increases, so too does the battery fire type of incidents increase.
What are lithium battery fires?
Lithium battery fires are a rare event, but they can happen to anyone. Lithium batteries in electric unicycles have been reported to spontaneously combust and cause damage during normal usage or charging. However, these events have generally been localized to cheaper batteries, poor quality control, and careless engineering of the electrical power system within the electric unicycle.
A quick search on Google will reveal that of the 4 major electric unicycle makers, e.g., Gotway (Begode), Kingsong, Inmotion, and LeaperKim (maker of the venerated Veteran Sherman), only one has a real reputation for sub-par quality control and preventable battery fires.
I’ll note that lithium batteries are found in many other products including laptops, tablets, vape pens, and smartphones. With proper safety features in place, a good battery management system (BMS), almost all of these lithium powered electronic devices are safe.
Of course, a lithium battery fire can happen and they are quite dangerous because of the heat they produce. When a lithium battery overheats, it can start to send off sparks and smoke. Over time, this process accelerates as the cells inside of the device become more unstable. This is when you need to be especially careful–keep your devices away from open flames or anything that could cause an ignition source! Lithium ion batteries are also prone to catching fire if they are punctured or the terminals touch one another.
A battery fire from lithium batteries in electric unicycles can produce very high heat as it is a metal based fire source (burning up to 2,000 celsius or 3,632 Fahrenheit). In badly designed or faulty batteries and associated hardware, an electric unicycle battery cells may not be able to contain overcharging (from a lithium battery charger) or high amperage current demands when the motor controller asks for it.
What can you do to prevent a lithium battery type of fire?
- Store your electric unicycle in a dry, cool place away from direct sunlight
- Do not expose your EUC to flammable materials, e.g., vapor from gasoline, that may be nearby
- Check the integrity of the lithium battery packs regularly along with other electric unicycle maintenance checks
- If a lithium battery appears swollen (like an under inflated balloon), or feels soft and spongy compared to a new battery pack, replace the lithium pack unit as soon as possible
- Make sure battery connectors are clean from dust, debris, and dirt
- Ride your EUC within the motor specifications for power demand, e.g., high amperage draw for long periods of time can overheat lithium batteries and control boards
- Use smartphone apps for your EUC with high temperature warnings
- Don’t leave your EUC attached to a charger longer than necessary
- To stop battery charging, unplug your charger from a wall outlet, before removing the plug from your EUC. Similarly, to start a battery charge, plug your charger into the EUC, before plugging the charger into a wall outlet.
- Don’t leave your EUC in a car with the windows closed when the ambient outside temperature is higher than 25C or 72F
How to care for your electric unicycle and its lithium battery
One common strategy to reduce the risk of lithium battery fires is to keep your electric unicycle in a cool, dry place. Keeping it out of direct sunlight or in a high-temperature location will also help, as they are the most likely locations for the battery to overheat. Finally, keeping it away from flammable materials like oil or gas will also reduce this risk.
You can also take steps to check your electric unicycle for signs of wear and tear on the lithium battery before use. You can do this regularly or after a crash or hard drop of your electric unicycle. I tend to open up my electric unicycle for regular cleaning and checks every 500-600 miles of riding.
If you notice any scratches around where the charger connects to the battery, you should replace them immediately. The dust near the connectors between the charger and electric unicycle might be an indication that there is dirt inside of it–if you see this, you should clean the connector and battery with a dry cloth.
If any of these signs are present–or if the lithium battery is swollen in size–be sure to not use your electric unicycle until it has been checked by a professional. This will reduce potential risks of fire from an overcharged lithium battery.
Another way to avoid battery damage that increases the risk for overheating and fire is to reduce the stress on the motor, which in turn will reduce stress on the battery. You can do this by not riding up or down really steep hills (beyond what your EUC is designed to take). Take a break to cool off your electric unicycle if you notice it is overheating.
Side note: For best riding performance, a lithium battery should be discharged in ambient temperatures as close to room temperature (25C-72F), if possible.
You can use in-app warnings for overheating temperature inside your electric unicycle. I set mine to around 140-150 Fahrenheit, which is fairly low compared to some others, and surely below the threshold for melting parts and battery overheating.
Finally, if you live in a hot climate, don’t leave your electric unicycle in a locked car with the windows up. A car sitting in direct sunlight will have a very hot interior within 20-30 minutes, with reported temperatures above 120F, even with outside ambient temperature around 70F. Ultimately, don’t leave your electric unicycle in a hot car, and keep it well-maintained to reduce risk of lithium battery fires.
Final Thoughts
Electric unicycles are a safe way to travel, but you should be aware of the safety of lithium batteries. There have been reports in recent months of lithium batteries in electric unicycles spontaneously combusting under normal use. It’s important to know the risk and why they are happening, so you’re not risking your life with faulty parts or user-error.
Fortunately, there are ways to prevent a lithium battery fire and reduce this dangerous risk. Make sure you’re purchasing an electric unicycle from a trusted brand that has higher safety certifications in place than the required UL standard. It’s also important to have your electric unicycle serviced regularly by individuals who are experienced with keeping up with the latest technology.
Overall, I think the risks of lithium batteries in electric unicycles are quite low when you take precautionary measures. A lithium battery fire is an alarming risk, but you can reduce your chances of injury by being aware and careful with how you use them. When you know the signs and risk factors, it can help you stay safe.
Are you worried about lithium batteries starting a fire with your electric unicycle? Are you taking an extra precautions that help you feel comfortable? We’d love for you to share! Leave a comment below.