On my ebike, how can I avoid “range anxiety”?

QUESTION: I love my new ebike, but there are so many variables that can affect how quickly the battery will drain that I’m avoiding long rides for fear that I’ll use the battery charge up before the ride is over. How can I figure out how long the battery will last before I start riding? —Duane R.

RBR’S STAN PURDUM REPLIES: You’re absolutely right about there being many variables that affect how quickly your ebike battery drains. They include trip distance, terrain, wind, temperature, motor efficiency, the condition of your bike, the point at which your battery shuts off (to avoid being damaged by a complete discharge) as well as your weight, the speed you ride, the assist level you choose and the force with which you pedal — and probably some more things I haven’t thought of. In fact, there are enough factors in play that there’s even a term for the sort of fear you mention: “range anxiety.”

When ebikes first came out, the attempts to estimate how long a battery charge would last were often based on math formulas, such as voltage (v) x capacity(ah) for watt hours (wh) then divide watt hours by your motor watts, as for example, 48v x 12ah = 576wh / 1000w = 0.576 (I borrowed this from an EBR forum thread from 2016). All well and good, I suppose, but such formulas always struck me as barely one step above useless for the average rider. Even if you figure out what all those electrical symbols mean and where to find the numbers that match them on your ebike, they don’t account for the inevitable variables over the actual course of your ride.

Fortunately, today, the apps that come with some ebikes provide more practical ways to avoid getting stuck on a route without e-power. For example, my e-steed is from Specialized, and all their various ebikes models are set up to be managed via an app (the latest iteration of which is unimaginatively called “the Specialized app” — not to be confused with its earlier version called the “Mission Control app,” which has now been discontinued). In any case, you load the app on your smartphone, and among other things, it enables you to input how far you want to ride and how much battery you want to have left at the end of the ride, or alternatively, you can input how much time you want ride and how much battery you want to have left. In both cases, the app will help you reach your stated goal by monitoring the battery usage and limiting how much you can draw from it along your ride so as have the specified level of battery charge remaining when you finish. (Here is a video that describes the Specialized app procedure. Start watching at about the 9:40 point.)

Of course, when you’re trying to keep up with the hammerheads at the front of a group-ride peloton, you may not like a power-conservation method that limits your battery draw at the app’s discretion. As an alternative, you can use the same app to adjust what percentage of power each of the assist levels provides (start watching the same video at about the 3:45 point) and then choose the assist level you want.

If your ebike is not a Specialized, you might find help from this article, which compares several ebike apps (disregard the now defunct Mission Control app, which is still on this list.)

If none of these options work for you, there are still two things you can do to give the boot to range anxiety.

The first involves record keeping. Make a chart where you keep track of each of your rides in terms of wind, terrain, miles covered and speed, and then note what percentage of battery charge you had left — and if you got to the point where the battery shut down, note that as well. Eventually, this record will give you enough data to estimate how far you can go under e-power under various conditions. 

The second option is to carry an extra battery on your bike. Admittedly this adds weight to the bike, which will slightly reduce the range of your first battery, but it’s unlikely that you’ll want more range than the two batteries together will provide. I was on a week-long riding adventure with a group last year where some days’ rides were as long as 75 miles. A sag vehicle travelled with us. One rider on an ebike had two batteries but left one in the sag, and simply swapped them out at the lunch stop.

I have purchased a second battery called a “range extender” made especially for Specialized ebikes, which fits into a water bottle cage and adds 50% more range. From past experience, I know I probably could have reached the 75-mile mark on the main battery alone, had I been on level ground and was content to ride in Eco mode (the lowest assist level). But our route involved a lot of climbing, and to ride with the other riders, most of whom were younger and on regular bikes, I wanted to use a higher assist level, and the two batteries made that possible — and fun! 

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Stan Purdum has ridden several long-distance bike trips, including an across-America ride recounted in his book Roll Around Heaven All Day, and a trek on U.S. 62, from Niagara Falls, New York, to El Paso, Texas, the subject of his book Playing in Traffic. Stan, a freelance writer and editor, lives in Ohio. See more at www.StanPurdum.com.