State of Charge
From Unofficial Zero Manual
- SoC is a porportional representation; a fraction, so it is only applicable with a known total or max.
- Riders all have experienced different ranges under different temperatures, various environmental conditions etc.
- So full is really a subjective term, like asking when is a ballon full? Before it pops? But if you fill it with cold air then move to a warm environment, it pops.
- Paraphrase of ElectricZen's explanation
- SoC is most easily calibrated using the battery pack's voltage at rest or near rest.
- SoC Indications per protomech
- The mobile app appears to simply show kWh using Zero's max capacity rating, i.e. present voltage times present amp hours.
- The voltage and amp-hours are likely to be correct, but the kWh readout is a rough guide at best.
- The percentage reading adjusts to the estimated pack maximum over time, so if the pack ages, the reported Ah and kWh readout will decrease, but not the maximum percentage.
- Variance across Battery Pack Years
- The sensors measuring current and temperature for the battery pack improve over the years, impacting SoC indication.
- One can find multiple complaints of going into limp-home mode at 5-15% from 2014 SR owners, for example.
- 2017 model year bikes appear to have an increased range of current sensor calibration quality, improving that year's estimations.