The battery on an electric bike requires a high level of technology in the manufacturing process which causes the battery to be the most expensive component. The progress of electric bikes to date has been dependent on the lithium ion battery. Earlier models of electric bikes did not gain widespread acceptance both because cycling itself was less popular and the old sealed lead acid batteries were heavy and had a small range per charge that limited their use.
Modern lithium-ion batteries have a much higher energy density than previous types. The range/charge on the bikes we sell is typically up to 30 to 70 miles depending on the motor/battery system being used. To get this range there are a few requirements such as using the lowest level of assist, flat ground, no headwind, etc. Realistically most e-bike users will get somewhere between 50% and 75% of the optimum range when using e-bikes in the real world.
Most of the batteries on our bikes will take between 3-4 hours up to 6 hours for a complete charge. The great thing is that the first 80% of that charge will be done in approximately half that time and then the charge rate slows down for the last 20% so the individual cells can be charged uniformly.
Battery storage tips are as follows.
- When storing for colder months, or any period with limited use of bike, charge the battery and then check once a month or so to make sure battery maintains some charge over the downtime.
- Rechargeable batteries like to be charged in temperatures above 45 degrees. This will give you a complete charge and also maintain the charge longer than storage in a cold environment. Charging is a chemical reaction and this reaction slows down in cold weather temperatures.
- Lithium-ion batteries can also be charged as often as you want. There is no memory problem associated with these batteries.
An important thing to note with regards to overall battery life is it is very dependent on the system being used on the bike. Battery life expectancy is determined by the number of full charge cycles. When charging a battery you are pushing electrons into the battery for storage and then pushing them out to do work. This transfer of electrons in and out is what eventually causes the battery to loose its ability to store energy. All of the batteries we sell will have a life span of approximately 1000 full charge cycles. This is true whether the bike they are on will get 30 miles of range or 70 miles per charge. The range per charge has a large effect on overall battery life because if each charge goes a longer distance then battery will also have a longer life. For example if your bike averages 20 miles/charge the overall life of the battery would be around 20,000 miles whereas if the range is 45 miles/charge the overall life of the battery would be around 45,000 miles. The bikes that are more efficient are generally more expensive in the beginning but as I showed they can cost less over their life time because the more efficient bike will not need the battery replaced as soon.
I hope this information helps in your understanding of e-bike batteries and some of the considerations when making an e-bike purchase.