eBike Battery Cell Life - How long do 18650 cells last?

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eBike Battery Cell Life

Cycle life is a hotly debated subject, but here’s what I know. A battery is cycled once every time you charge it and then discharge it. It doesn’t matter how much it is charged or discharged, just that one happens and then the other. If you charge it 20% then use 10% that’s still one cycle. Most cells have a cycle life of 500-700, meaning that’s how many times they can be cycled before they lose more than 20% of their capacity permanently. There are ways to extend cycle life. The best way is to only cycle the cell between 3.1V-4.1V. This will extend cycle life to 1000-2000. However, this requires a special BMS which you probably can’t get because the battery companies don’t want you to have it.

Battery Damage/Issues

The two main types of battery issues are loss of capacity and BMS failure. Loss of capacity can happen if the battery gets too hot or cold, if it is over charged or over discharged, or if the cells get too far out of balance. BMS sometimes have minor failures that just stop the battery from working at all.
 
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