Inclines and Steep Hills
The first thing that drains your battery is going uphill. The more power you use when going uphill, the more power your battery will use. This is because of the extra work needed for the motor to push against gravity. Terrain is also a factor here, where you can expect your battery to drain more if riding through mud or gravel as opposed to pavement or solid dirt.
Weight on the Bike
The more weight your electric bike is carrying, the more power the motor needs to put out to get you going from a stop or to even climb hills. This requires the motor to pull more power from the battery, more so if you are using throttle only instead of pedal assist. Ensure that you are planning ahead if carrying a lot of weight by bringing a secondary battery for backup!
PAS vs Throttle
Using throttle only will draw more power from your battery than if using pedal assist (PAS). Pedal assist not only helps give you power to your pedaling, but you will also help prevent your battery from draining too quickly.
Going for a ride in cold weather or extreme cold temperatures can render your battery to perform poorly. When temperatures start to reach freezing levels (0ºC or 32ºF), you can expect to have less than 50% of your battery life.
Take into consideration of other factors as well, such as if you’re riding against the wind. This resistance requires your motor (or your pedaling!) to push harder, thus draining more battery. Check your tire pressure. This can also play a factor when riding on different surfaces. Tires that are too low PSI can result in the treads making too much contact with the riding surface, giving you drag and preventing you from coasting properly.