On My 2000 5 spd I notice a drastic usage of battery power when making long hill climbs. Trips to San Diego on I-8 I will see My battery deplete and recharge a minimum of 4 times. I will drop to 4th as soon as I hit the grade and keep RPMs at around 3000-3500. as the battery level drops I will drop to 2nd and maintain RPM at approxiamtely 3500-4000 and recharge battery while maintaining speed up hill (this is a steep long grade about 18 miles of grade). On flat ground which is what most My commute is I can maintain a charge level of about 3/4 most times and notice a "recalibration" discharge about every 2 weeks (my comute is about 80 miles day).