From Unofficial Zero Manual
After "spirited" riding especially on an SR or a DSR a temperature icon may flash, indicating high temperature. If temperature continues to build it will go solid (p. 4-14 2014 Zero SR owners manual)
- Pre-2012 Recommendations
- On pre-2012 models, it is important to slow down and let the motor and electronics cool as there are no inbuilt protections.
- 2012+ Recommendations
- On 2012 and newer Zeros, the controller will automatically reduce phase current as the motor heats up which reduces performance and motor heat.
- This gets more aggressive as motor heat increases until power is reduced to a point where the motor is shedding heat as fast as it can generate it.
- The 2014 and newer SR and DSR motors have higher temperature magnets, and it is normal to see 120+C under spirited riding.
- IPM Design Factors
- The 2016 SR/DSR/FXS motors (and S/DS motors for 4-brick variants) have an interior permanent magnet (IPM) design that reduces the heat produced and reduces the stress from heating by distributing the heat generated, so they appear to operate cooler in the same conditions for longer periods of time.
- It has been said that with an IPM motor, the controller becomes the limiting performance factor.
- Battery Overheating
- Repeated iterations of highway riding and rapid charging can cause battery overheating.
- The contactor opens up above 50C, preventing charging or operating the bike.
- Once you are stopped, without airflow on a hot day, it may be difficult to proceed for some time.
- Slow to 55-60 mph for the last miles before charging is reportedly enough to cool the battery enough to allow rapid charging.
- Reduce charging rate to at or near 4kW (or 0.4C) to minimize the heating produced while charging.
- Disengage the onboard charger while charging, since the heat it produces conducts directly into the bottom of the battery case.
- Year over year, newer battery designs have lower internal resistance and tend to produce less heating internally so will perform better.