What an E-Bike Display Does and What It Does Not

Your screen is lit, but you aren't sure what it's there to do. Or the bike feels different and you're wondering if the screen is to blame. Start with what the display is, because it's less than most owners assume.

The screen is mostly a window

A display on an e-bike is the part you look at and press. It shows information and takes your button presses. That's close to what a bicycle computer does. Wikipedia says a cyclocomputer "calculates and displays trip information"¹. An e-bike screen adds readouts for the assist and the battery.

Most e-bike screens have a few buttons too. On a plain bike computer, the source describes "one or more buttons that the user can push to switch the value(s) displayed"¹. The same idea applies on your handlebar. A press cycles the numbers or changes a setting.

What the screen reads and what it doesn't

Some figures come from sensors on the bike. A speed sensor, for instance, "measures bicycle speed and the distance traveled by detecting wheel rotations"¹. The screen only reports that figure. It doesn't create it.

The same goes for pedal-assist. Wikipedia says the motor is "regulated by pedaling"². The sensors for that feed the bike's system. The screen is just where you see the result.

So the screen does these jobs:

• Shows readouts such as speed, assist setting and battery charge.
• Takes your button presses, such as a change of assist level.
• Shows a code or warning when the system reports a problem.

It doesn't do these jobs:

• It doesn't push the bike along. Other parts of the bike do that.
• It isn't a repair tool. It points at a problem. It can't fix one.

Is the display the same thing as the controller?

No. This trips up many owners, since both can be called "the electronics". The controller is a separate unit that manages the motor. The display is the front panel you look at and press. Display, Controller and Remote: How the Parts Fit Together sets the two side by side.

Maker pages name the parts separately. One maker's help centre lists a fault for the button pad. It says the "HMI button may be damaged or the connection may be broken"³. HMI is short for human-machine interface, a trade term for the screen and buttons you use. Because a code can point at the button pad, a bad button doesn't have to mean a bad motor.

When the screen shows something odd

Work through these in order.

1. Check the obvious. Is the battery seated and the system switched on? Follow your own manual for how.
2. Look at what's showing. A symbol is a status. A number or letters may be a code. Common E-Bike Display Icons and What They Show covers the symbols.
3. Read the manual for your exact model. Screens differ between makers, and a symbol can mean different things on different bikes.
4. Note any code. E-Bike Error Codes: How to Look Yours Up explains where the maker lists it.
5. Contact the maker or your dealer if the problem stays.

Not every message is a fault. The same maker lists a reminder: "Error code 113 serves as an e-bike maintenance reminder"³. A code on your screen may be a prompt to get the bike looked at by a dealer.

What a screen can't tell you

A readout is a figure worked out from sensors, and it depends on the sensor and the settings behind it. A wrong wheel size setting will skew speed and distance (see the trip data page). A battery gauge is an estimate too, which the battery page explains. Treat the screen as a guide, and treat your manual as the last word on how your bike behaves.