Seeing how expensive batteries are, I decided to put together a little guide of how you can maintain yours, and maximize its life. Lithium-ion batteries are used in many different electronics: Phones, Laptops, Electric Cars, Power Tools, and many other household items. The reason for this is because they can hold a lot of power while taking minimal space (ideal for portability)
I'm sure you've noticed how when you get a brand new phone, the battery lasts 2 days before it dies. As the batteries goes through more charge cycles, it is common for performance to decrease.
As a result of the fluctuations in temperature that the cells experience when being used, and the age of the battery, they do not last forever. Batteries are expensive, and I think it's important that you know how to get the most out of yours. Here we go.
How To Maintain Your Battery
If you leave your battery in the heat, charge capacity will slowly decrease. The best thing to do would be to bring the battery inside whenever you park it. For bikes without removable batteries, I have bad news: Unless you can bring your bike inside wherever you go, your battery isn't going to last as long. LUCKILY, our ebikes all have removable batteries! Just remove it from the frame, and bring it inside.
Contrary to popular belief, overcharging is not as big of a problem as some think. As the battery reaches full capacity, the current will decrease, only providing enough power to hold the charge, and keep it at 100%. What you should worry about however; is something called the Depth of Discharge (DoD). Depth of discharge is the measure of how much energy you use before charging your battery. One of the problems with lithium-ion battery technology today is they they handle DoD poorly. It is best to keep your fully charged, depleting it as little as possible each time you ride.
Realistically, if you plan on actually using your bike, you're going to have to use the battery in sub-optimal conditions: You're going to ride it on extremely hot days, and you're going to go far enough to drain the battery low. You should do your best to extend the life of your battery, but it shouldn't stop you from actually enjoying it. Take it inside if it's hot out, and charge it up if you have some time before your next ride.