Gen2/Calex Charger/Behavior

Calex Charger Behavior

Per CANBUS diagnostic reply, the Calex charger operates as a CC/CV mode charger.

• Constant current (CC) mode is the default operational mode.

  The charger attempts to deliver a target amount of current to the battery.

  This means that the charger's power input is proportional to the battery's voltage at that moment, which rises from low state to the high state of charge, so charging will be slower at low voltages (< 20% SoC).

• Maximum allowed battery voltage: 116.4V (Confirmed via charger self-report over CANBUS)

  When battery voltage reaches or exceeds this value, the charger enters a constant voltage (CV) mode.

  Since the rate of charge dynamically adds voltage to the pack, the taper eases off this addition so there's a stable charge equilibrium at the end.

  Tapering behavior is observed to reduce output current in increments of 1A and typically starts at 12A.

• Current taper cutoff: 10A (Confirmed via charger self-report over CANBUS)

  The charger will cut to 0 output rather than taper below this value.

• Maximum allowed current: 65.535 A (Confirmed via charger self-report over CANBUS)

  This is a meaningless binary value.

Overcharge Protection

The charger is limited by the manufacturer to a range that matches Zero's battery safe range.

The charger is connected to external AC sources and is therefore a vulnerable component while plugged in.

Per Re: Change to Charging - Leaving Bike Plugged In

• The charger is an isolated power supply with suppressors on the input.
• So, if a surge were big enough, the suppressors could fail short.
• Then the circuit breaker should fail after that.
• The BMS and the rest of the bike is completely isolated from the charger, so there's no current path to them.

This is why some people on this forum report their charger is dead, but the bike is fine, and there wasn't any fire. Most of the time Zero, replaces the onboard charger for them.

Worst-case scenario

• BMS unresponsive
• MBB unresponsive
• Contactor welded
• Charger outputs more than 117.6V

In the event of all these holding (extremely unlikely), there is some risk of a fire.

This is probably why Zero asks you to check on the bike every 72 hours to make sure the bike is still responding and the BMS is still alive.