The battery is one of the most important and costly electrical components on an e-bike. It requires great care to maintain proper functionality over time.
Unfortunately, many new e-bike owners experience a significant deterioration in their battery performance for failure to adhere to the manufacturer’s recommended best practices.
To avoid getting trapped in the common pitfalls, the following is a guide to the ideal operating temperatures as far as e-bike battery storage, usage, and charging are concerned!
What are E-bike Batteries Made of?
A great percentage of the modern electric bikes come with a Lithium-ion battery, and this is what we will be referencing throughout the guide. Li-ion batteries have high energy density and come in a variety of chemistries, including Lithium Manganese Cobalt, Lithium Nickel Cobalt Aluminum, Lithium Nickel Cobalt Manganese, and Lithium Polymer.
Inside the e-bike battery, you will find several smaller battery cells that are typically in the 18650 format. These cells are a little bit larger than an AA battery and carry a charge of 1.5V, while the capacity ranges from 3200-3500mAh.
The smaller cells are arranged in either series or parallel and together form a larger e-bike battery. Mostly, the number of cells in each battery, as well as their arrangement, will vary depending on the capacity (usually 400Wh-1000+Wh) and voltage (usually 36V, 48V, 72V).
The Bosch power pack for example contains between 40 and 50 individual cells.
CAUTION Homemade e-bike project can be dangerous.
Be very careful when you build your own e-bike pack.
Caring for an E-bike Battery
Most electric bikes are powered by either a 48V or 36V drive system. You always want to ensure you have the right type of charger for your specific e-bike battery and that it works fine. If you bought your e-bike from an online retailer, then greater caution needs to be taken as some of these batteries end up sitting in warehouses and shipping containers for an extended period without getting the proper care.
Before taking the bike for a ride, plug the battery into the charger and charge it to full capacity. You’ll know it is full when the LED light turns from red to green. After a full charge, you can take your e-bike for a test ride to ensure there’s no unexpected voltage sag.
Ideal Charging Conditions for an E-bike Battery
The ideal charging conditions for an electric bike battery involve slow charging and cool temperatures. Manufacturers normally suggest charging the battery at a temperature between 5 and 45 degrees Celsius (41-113 °F). You shouldn’t charge your lithium battery in low-temperature conditions.
Similarly, batteries should not be charged at temperatures higher than 45 degrees Celsius, and most battery chargers won’t even function in temperatures above 50 degrees Celsius.
Ideal Discharging Conditions for an E-bike Battery
When it comes to discharging your battery, the recommended temperature is around room temperature 20 degrees Celsius (68 °F) or slightly lower than this. The scientific explanation behind the ideal temperature conditions is that warmer temperatures tend to have a positive effect on the battery capacity.
This means you can get more range from the battery if everything remains the same, except for the temperature. Although the capacity of the battery increases, warmer temperatures will also reduce the shelf life of your battery if left exposed for too long.
Another aspect to note is that the battery capacity is greatly reduced once temperatures begin to edge closer to or below 0 degrees Celsius. However, this condition is only temporary, and the capacity will be restored once the battery temperature returns to its normal range.
Ideal Storage Conditions for E-bike Battery
There are many ways to store your bike, standing, suspended, hanging or vertically mounted. There is even a storage device that turns your bike into a stationary exercise bike for indoor cycling. Just don't forget to switch off your battery.
When you want to store your battery, remember to first remove it from the e-bike. This is because temperature and climate changes can easily corrode the battery contacts.
It is advisable to get the battery off the e-bike for proper and safer storage. Applying a thin layer of grease on the battery aid to protect the contact points from corrosion. Furthermore, experts recommend that you shouldn’t store the battery when either fully discharged or fully charged.
Ideally, the battery should have a charge capacity of 30-80% or an equivalent of three bars before storage. Ensuring the battery has a partial charge for storage serves to help it retain its capacity longer.
Temperature plays an important role during battery storage as it directly affects the capacity of the lithium batteries. Scientifically speaking, the lithium battery powder found in the battery cells reduces its electrical resistance as the conditions warm up.
In other words, the battery will discharge faster in warmer conditions and subsequently require charging more often. The best way to store a lithium battery is in cold conditions whereby its internal resistance is at its highest and will maintain a full charge for longer.
If you have to store your electric bike outside, be sure to get a bicycle cover for it. This will help prevent damage to the battery, and keep the bicycle dry and reduce rust. Here is an bicycle cover which I personally recommend, as I purchased this for my bike in the fall.
- OUTDOOR PROTECTED: Side Material: 190t nylon, high density and durable. Silver material is 40+ UV protected, 600D oxford fabric....
- PORTABLE : The over folds down to a compact size and with a high-quality drawstring bag with straps and buckles. Easily strap the...
- LOCK COMPATIBLE HOLES: Through the holes at the bottom, you can lock your bikes to the stand or a pole using a chain lock or U...
Never leave your battery charging for the whole time it’s in storage. Although it may not affect its life, it can raise the danger of electrical fires occurring. You’ll be better off investing in a wall-plug timer to automatically switch off the main current once the battery is fully charged.
To store your e-bike battery, find an area with a temperature between 0 and 20 degrees Celsius (68 °F). Anything in between will be perfect for your battery and will go a long way to prolong its shelf life.
Things to Watch Out for
When charging, storing, or using your lithium e-bike battery, the following are temperatures you want to completely avoid:
Storage- Anything higher than 20 degrees Celsius is too hot when charging your e-bike battery
Riding- You should ride your bike in temperatures under 60 degrees Celsius and not higher
Charging- For charging, stay below 45 degrees Celsius
Storage- Store your battery in temperatures above 0 degrees Celsius; never store it under -10 degree Celsius
Riding- Use the battery in temperatures above -10 degrees Celsius, and if you want to ride your e-bike in colder conditions, then leave the battery inside
Charging- Charge the battery in temperatures above 5 degrees Celsius
The worst thing that can happen when temperatures are too high is the venting of the battery, which results in either total failure or even a fire breakout!
Keeping Your Battery Warm in Winter Weather
If temperatures outside fall below the recommended 0 degrees Celsius, you want to want to keep the e-bike battery at room temperature and only mount it on the bike when you want to head out. This ensures your battery starts at a warmer temperature, hence improving its performance during usage.
You can look for a Neoprene or thermal cover of the right size to wrap around the battery so that it remains warm when temperatures are too cold. This is particularly crucial if you’re setting out on a long journey in freezing conditions.
Note that once you begin to ride your electric bike, the battery will generate a slight amount of heat to slow down its cooling from the cold outdoor temperatures. Ultimately, if it’s too cold outside, both the performance and capacity of the battery will deteriorate compared to warmer days.
However, following these tips should let you squeeze slightly more range from your battery.
Keeping Your Battery Cool in Summer Weather
The best way to protect your electric bike battery from the hot summer weather is to keep it away from direct sunlight. This should help to reduce the battery’s temperature by a couple of degrees and prevent overheating.
Additionally, you don’t want to place your battery inside a car that is in direct sunlight. Typically, cars can get to over 75 degrees Celsius on hot days, which is way more than the highest temperature recommended for storing an e-bike battery.
Generally, lithium-ion batteries are preferred by most e-bike manufacturers for their reliable performance down the line. While these batteries age and drop in performance with every cycle of use, the above tips are useful if you want to extend the life expectancy of your e-bike’s battery.
As long as you adhere to the recommended maintenance practices during charging, usage, and storage, you’ll be able to squeeze a few extra years from your battery while still enjoying a decent level of performance from it.
Last update on 2023-06-01 / Affiliate links / Images from Amazon Product Advertising API
I have new Ancheer e-bike. I live in the desert. My house temp is in the 90s F during summer. They say the battery should not be stored in temp over 75 F.
My refrigerator is at 45 F. I want to put it there, but Ancheer worries about condensation and water getting in it.
I would love your opinion. I expect to use the bike 12 mos/yr.