What's the best maintenance practice for batteries?

1. Avoid excessive heat/leaving the battery under the sun.
   To prolong an electric bike battery, avoid temperature extremes both in usage and when you are charging the battery.
   Ideally, batteries should be stored at room temperature:  50 °F – 77 °F.
2. Recharge your battery before it's fully drained. It's not a good idea to fully drain your battery.
3. Do not leave your battery fully charged for a long time. While this may seem like a good idea, keeping your battery 75% charged while storing is a better practice for the longevity of your battery. 
4. Do not keep the battery on the charger for long periods of time (>12 hours).
5. Do not use fast chargers as they may cause extreme heat. 
6. Do not store an empty battery.
   Do not leave the battery idle for months at a time, even if you're not using your bike, please make sure to charge your battery periodically to keep the battery charge levels between 40-70% at all times in order to avoid degradation. 

And please do not forget that this is the most expensive part of your ebike which needs a little more attention than the other parts of your ebike.