Elevation Gain: For hill-climbing, expect about 3 feet of elevation gain for every volt-amp-hour. For example, a stock battery pack (24-volt, 12 amp-hour) will take you up about 800 feet without pedaling (3 feet X (24 X 12) = 864 feet). Another way to compare performance is the ability to gain elevation. Here are some anecdotal estimates:

• ZAP DX system with 13-lb SLA battery can gain about 450 feet of elevation.
• Currie U.S. ProDrive system with 20-lb SLA battery can gain about 800 feet of elevation.
• Betterbike Model 20 with two 20-lb SLA batteries can gain about 1600 feet of elevation.
• EV Global 36-volt bike with 20-lb SLA battery can gain about 800 feet of elevation.