While we have all been using things with rechargeable batteries for years, there are now a lot more items coming with battery power. While most people are comfortable with charging and using something like a cell phone, things like electric cars and bikes are still new for a lot of people. Their batteries are big and expensive. Does how we use and charge our new vehicles affect the life of the batteries, and, if so, how do we maximize our battery life? Are there legitimate safety concerns with larger lithium-ion batteries? While there is no shortage of rabbit holes we could dive into, there are a few reminders that will help keep you safe and keep your e-bike battery happy for many miles.
When it comes to the battery in your new e-bike, these are the four main things you need to KNOW.
Keeping the charge around 25% to 80% is typically fine for long-term storage (but reference owner’s manuals for more specific storage charges). Never overcharge or leave unattended.
Number of charging cycles matter for the longevity of batteries (every full charge going from 0% to 100% is called a charge cycle).
Only at room temperature and when turned off should your e-bike be charged.
Winter storage is at room temperature.
Below is a deep dive into the most frequent questions regarding electric bike battery safety.
1. Storage
When not using your e-bike, it is best to store the battery somewhere that isn’t in direct, hot sun but is not too cold and stay above freezing.
There are specific storage recommendations based on the model of e-bike owned. For example, for a bike with a removable battery, remove the battery and store it at or above 59 degrees Fahrenheit; otherwise, bring the bike inside. Jonah Matthes of ReCharged Commute recommends making sure the battery is optimally at a maximum temperature of 68 degrees Fahrenheit when storing to ensure its safety and performance. A dry place at room temperature where moisture cannot get in not only is the best for the battery but is necessary.
Knowing how to store an e-bike and battery ahead of time is helpful so an informed decision can be made before buying. If there is no indoor bike storage, an e-bike with a removable battery may be considered.
2. Charging
If you aren't using your e-bike over the winter or take a month off from riding in the summer, store the battery at about 25% to 80%. You should also charge the battery about once a month to get it back into that range, as it will lose power while sitting around.
Specific battery charging recommendations will also vary by manufacturer. For example, guidelines from Specialized state that the battery should be recharged to between 25% and 75% every three to six months, depending on the model of electric bike. Every full charge going from 0% to 100% is called a charge cycle. Your battery life will depend on and be decided by these charge cycles. Batteries will lose total charge capacity over time; for example, the batteries used by Specialized will generally lose 25% to 30% of their capacity after 300 to 600 charging cycles. Some lithium-ion batteries will conservatively last about 750 cycles.
When using a bike, if you don't need a full charge for your next ride, it's fine to charge a little less. Not always charging to full will reduce your expended charge cycles. Jonah Matthes recommends that charging an e-bike battery to just 80% to 90% capacity is fine in most cases. Enabling the Charge Limit on the Specialized Mission Control app will limit a Turbo battery to an 80% charge, with a full 100% charge every ten charges for calibration.
If you are riding in the winter, your battery will stay warm while being used during the ride, but it's important to charge the battery while warm too. You will always lose a little battery range when riding in the cold, but you will ensure you have a full battery if you charge it indoors before the ride. Also, never charge your bike while it is turned on.
Take into consideration the power range used during a typical ride (low versus high), where you're likely to be going (flats versus hills) and how much is ridden to figure out the best e-bike and battery choice.
3. Safety
Every now and again there is a report of an electric bike catching fire. Jonah's article on ReCharged Commute explains that the risk is that, although rare, electric bike batteries can explode. These fires are caused by damaged lithium-ion battery components.
There has been approximately one vehicle fire for every 205 million miles driven by a Tesla from 2012 to 2020 according to Tesla, who use lithium-ion batteries within their vehicles. Data from the United States Department of Transportation and the National Fire Protection Association show that there is typically a fire in traditional vehicles for every nineteen million miles. The odds of a properly cared for lithium-ion battery catching fire are quite low. Taking necessary precautions greatly reduces fire risk while also expanding battery life. Even with proper care, there are still some risks to be aware of.
To help prevent battery fires, here are some tips:
- Never leave a battery charging unattended or overcharge it. Many of the stories of shops catching fire are due to e-bike batteries being left charging unattended overnight. To clarify, when we say "unattended" we don't mean you have to watch your e-bike battery charge, but just don't plug it in and leave or go to sleep for the night.
- Do not store a battery fully charged, too hot or too cold. Make sure the electric bike battery is safely stored when not in use.
- Purchase batteries from a trusted source, such as Specialized, Bosch, Shimano or MAHLE.
- Never change a battery or use a damaged battery. One of the ways lithium-ion batteries can catch fire is through being damaged.
- Always use the best safety practices. Reference the owner's manual for any model of electric bike for more specific safety recommendations.
4. Warranty and Recycling
Manufacturers warrant batteries for a defined time. For example, Specialized brand bikes usually have a warranty to keep 75% of battery life (or riding range) at three hundred charge cycles or two years - whichever comes first.
Check your specific bike information for details on your bike's warranty. After the end of the warranty period, check with the manufacturer whether they have a post-warranty program.
An e-bike battery recycling program was just launched in early March 2022 from Call2Recycle, a company who works with recyclers to divert lithium-ion batteries from landfills. Currently, Skirack is accepting batteries from Specialized and Cannondale (with a recycling fee of 15 dollars).
Electric mobility is super fun and here to stay! With every year technology seems to make it easier to operate and makes the batteries smaller and even longer lasting. Combining these high-tech batteries with the above ground rules goes a long way to improve safety and battery performance. Keep the four things in mind from the beginning of this article, and you will be in the KNOW!
If these suggestions are followed, miles of enjoyment will be ridden on your e-bike and more confidence will be felt around it. Have fun out there, and ride responsibly!
- Collaboration between Doug Stewart, Jordan DeMatteis and Jon Kohn
Skirack Electric Bike Specialists
Sources
- Can an E-Bike Battery Explode or Catch Fire? by Jonah Matthes