Honda CLARITY Fuel Cell 2020 Owner's Manual page 18

High Voltage Battery
Because electricity generated by the fuel cells and through regenerative braking recharges the High Voltage battery, the battery does not
need to be recharged from an outside source; however, the High Voltage battery gradually discharges when the vehicle is not in use. If
allowed to discharge too much, the battery may become damaged.
If your vehicle is parked for an extended period of time, during storage for example, periodically recharge the battery to maintain sufficient
charge levels. At least once every three months, turn on the power system, and keep it on for more than 30 minutes to allow the battery to
recharge.
Excessive heat can also damage the battery. On hot, sunny days, try to avoid parking your vehicle under direct sunlight.
If the High Voltage battery becomes fully discharged or damaged and you are unable to start the FC system as a result, consult an
authorized Honda Clarity Fuel Cell dealer.
Temperature
When storing the vehicle, make sure not to expose it to extremely low temperatures: It may take a longer time to start in very cold
conditions or may not start at all until temperatures rise. If the temperature of the fuel cell or the High Voltage battery drops below –4°F
(–20°C), the fuel cells will not operate and, as a result, the vehicle will not start.
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