The Ultimate Guide to e-Bike Battery Care in Winter

For many, Christmas season is a time to kick back, relax and be astounded at how quickly the year has gone by. However, for business owners, entrepreneurs and independent contractors such as delivery riders, it's one of the busiest times of the year as consumers rush to order last minute gifts, groceries and food in preparation for their holiday festivities.

As a delivery rider, the last thing you want happening during this period is for something to go wrong with your e-bike battery (knock on wood) - presenting you with a very costly period of downtime, while others are out taking the jobs that could have been yours. Which is why today, we will cover the best ways to take care of your e-bike battery in winter, to ensure it stays in peak form all throughout the season.

The effects of cold temperatures on e-bike batteries.

Maybe you’ve experienced this before on your e-bike, or perhaps you’ve taken your camera or phone out in freezing weather and all of a sudden it goes from full charge down to zero in an instant. Now there is a reason for this and to understand why this occurs, let's take a look at what is happening inside the battery when it's operating in such low temperatures.

• Batteries work by turning chemical energy into electrical energy. When connected to a circuit, chemical reactions inside the battery create a buildup of electrons at the negative terminal, which naturally want to flow through the circuit to the positive terminal, providing power to anything hooked up to it. 
• Batteries, including the lithium ion (Li-ion) batteries commonly found in e-bikes, typically perform optimally at room temperature, or between 15°C and 35°C (59°F and 95°F). 
• When the temperature falls from 25°C down to -15°C (77°F to 5°F), the maximum state of charge (available capacity relative to the maximum possible charge of the battery) of Li-ion batteries drops by up to 23%; and when cooled to temperatures as low as -40°C (-40°F) the power and energy densities of certain Li-ion batteries can decrease by up to 95%!
• This is due to the fact that in low temperatures the chemical process inside the battery slows down, leading to a reduced charge transfer rate and lower overall capacity.
• What this means in a real life application such as riding an e-bike, is that in cold weather you will likely see a decrease in total battery capacity, decreased performance and increased battery drain.

To put this in perspective, an Australian insurance company attended to over 400,000 calls for flat car batteries in the winter of 2020, and Australian winters are nowhere near as harsh as some areas of the US or Europe! Granted, most car batteries use an older style lead-acid battery, however the same principles apply here to Li-ion batteries as well.

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How to take care of your e-bike battery in cold temperatures.

So, now that we understand why batteries tend to fail in colder temperatures, what is the best way to take care of your battery and make sure your e-bike stays healthy throughout the winter?

• Don’t store or leave your battery outside for extended periods of time - always bring it inside to room temperature where possible
• Charge your battery indoors at room temperature if charging to full capacity
• Never use a fast charger on the battery when it is exposed to cold weather
• Never put your battery in front of a heater to warm up, let it naturally come back to room temperature
• Expect reduced range in cold conditions

On Zoomo e-bikes, you may see an error code “B07” appear on your display after prolonged use in cold weather. This is by design and has been implemented to turn off the battery to protect it and ensure optimal lifespan and performance. You will need to bring the battery back to room temperature to turn it back on.

So, if you have been concerned about your battery performance in the cold or are hesitant to use your e-bike in winter, follow these tips and tricks to get the most out of your e-bike; and ride further and earn more this Christmas season.

Happy holidays and happy riding!

From your friends at Zoomo.‍

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References:

1. Ma, S., Jiang, M., Tao, P., Song, C., Wu, J., Wang, J., Deng, T. and Shang, W. (2018). Temperature effect and thermal impact in lithium-ion batteries: A review. Progress in Natural Science: Materials International, [online] 28(6), pp.653–666.
2. ‌Aris, A.M. and Shabani, B. (2017). An Experimental Study of a Lithium Ion Cell Operation at Low Temperature Conditions. Energy Procedia, [online] 110, pp.128–135.
3. ‌www.mynrma.com.au. (n.d.). How does cold weather affect your car battery? [online]