Many Optibike riders like to ride in cold weather, and some experience reduced battery performance as a result. Here is an explanation why, and what can be done about it.
The capacity of Lithium Ion batteries will decrease with colder temperatures. As the capacity decreases, the bike will run for shorter times and enter Safe Mode earlier. Run times can be extended on colder batteries by running in ECO Mode. If the battery is stored in a warm room and then ridden in colder temperatures, the battery capacity will be higher as the battery will warm itself during the ride.
Capacity Decreases at Colder Temperatures
The capacity of Lithium Ion batteries will decrease as the temperature of the battery decreases. The maximum run time is achieved at temperatures of 25C (normal room temperature). At 0C (32F) the capacity of the battery will be only 80% of the battery at 25C. At a temperature of -20C, battery capacity will be decreased to 60% of a room temperature battery. See chart below.
Keep the Bike Indoors Prior to Riding for Peak Performance
For best riding results, store the bike in a warm area and then take it outside to ride. If the battery is stored at 25 C and then ridden in air that is 0C, the battery will heat up as it is used and this will prevent it from cooling off, preserving the capacity. The exact amount of cooling of the battery will depend on the outside air and speed the bike is ridden. If the battery is left outside in 0C temperature and then ridden, the capacity will decrease to about 80%.
A Colder Battery Will Enter Safe Mode Sooner
When riding with a cold battery, riders will encounter shorter runs times, and the bike will enter Safe Mode earlier. Safe Mode is entered when the battery reaches a certain lower voltage and over rides the capacity gauge.
If you find the bike going into Safe Mode on colder days, try riding in ECO Mode, which has a lower drain on battery and this will keep the voltage higher and keep the bike form entering Safe Mode. Limiting acceleration and keeping the bike out of Boost Mode will also keep the bike out of Safe Mode.
Safe Mode Indication
Safe Mode has been entered when the Red LED on the headlight begins to flash. The power of the bike is reduced to less than 200 watts. Run Time in Safe Mode will vary from 2-10 minutes. Exact run time will depend on battery temperature and how old the battery is.
Reset From Safe Mode
If the bike does enter Safe Mode, early in cold riding, it can be reset by turning the bike Power Switch to off, waiting 10 seconds, and then turning bike back on. Then ride the bike in ECO Mode and allow the battery to warm up.