From Unofficial Zero Manual
The following factors speed up degradation:
- Hot Temperatures
- This causes the electrolyte to become more reactive. Farasis claims to have one of the most stable electrolyte blends in the business, and use a lot of proprietary tech to keep the cathode/anode blend as least reactive as possible, but the effect is unavoidable.
- High Voltage
- Again, The higher the potential between the cathode and anode, the faster the reaction between the electrolyte and the actives occurs.
- Very Low Voltage
- Below a certain voltage (2.0-2.2V/cell) the potential between the cathode and anode is such that the battery has used all its high potential lithium, and so it starts picking on the next easiest thing, which is the copper.
- This process is super ugly, as it electroplates the copper off the negative foils (anode) and electrodeposits it onto the positive foils (cathode). PERMANENT IRREVERSIBLE DAMAGE. This is super dangerous too, as the next time it is charged, that copper gets blasted back to the negative foils and lands wherever it feels like, as the anode isn't designed to deal with copper Ions. So they form big crystal sharp structures called dendrites, which at best can pierce the separator and cause high self discharge and gassing as the electrolyte nucleates (gas builds up, the cell goes to 0V and looks like a balloon) , or at worst, the dendrite is able to get a solid connection between the cathode and anode, and this causes the cell to short internally and results in fire.
- Luckily for you, Zero has an amazing BMS and pack topology that sips hardly any power from the cells in a key-off state, but you still can murder the bike by approaching 0% SOC as slowly as possible until it is at its absolute lowest SOC (state of charge) and the BMS shuts the bike off. What happens is that the bike has the smallest amount of reserve battery then, and the BMS sipping away at that small amount will eventually murder the cells over a period of several years.