1 It takes approx. 2  2 hours to fully recharge a completely exhausted battery at 23℃ / 73℉. 3  The time required to recharge the battery depends on the ambient temperature and battery's charge level.4  For safety reasons, recharging in low temperatures (6℃ - 10℃ / 43℉ - 50℉) will take a longer time (up to 4 hours). It takes approx. 2  2 hours to fully recharge a completely exhausted battery at 23℃ / 73℉. 3  The time required to recharge the battery depends on the ambient temperature and battery's charge level.