What is Wattage in relation to an e-Bike?

When you are looking to buy a new electric bike and glance at the specification some quoted figures may be new to you and likely confusing.  So let’s demystify one of them “Wattage”.  If you visit many online cycle stores you might see for example “Ecotric Fat Tire Electric Bike 26″ x4″ 500W 36V/12AH“, so what is the “500W” and how important is that number?  

A typical electric bicycle setup is a 36V (volt) battery and a 15A (amp) controller. Wattage is simply voltage multiplied by current so 36 volts x 15 amps = 540 watts

What Wattage should you look for when Buying an Electric Bike?

The benefits of a high wattage motor are very overstated. A street legal e-bike in for example Oregon can go only 28mph, and only 20mph unless you are pedaling. That’s achievable with even some 250 watt motors. In many states, the limit is 20mph, whether you pedal or not.

With most modern electric bikes equipped with the latest in motor technology, you’ll find that you get far more power than you need with 500 watts or less. There are many 250 watt motors that deliver as much torque as motors that are 500 watts or higher. The design of the motor and the gearing of the bike are far more important than the wattage of the motor.

Is there a downside to a High Wattage Electric Bike?

Higher wattage correlates to higher power consumption, so using a higher wattage motor means you’ll need a bigger battery to provide you the same range. The most expensive part of your e-bike is the battery, thus a larger motor, requires a larger battery which leads to higher cost.

If you plan to carry weight on the rack or panniers, you might think it a reason to go for a high wattage e-bike but a motor rated at 350 watt motors should do you fine and save you some money on that initial outlay.

So can I buy and use an Electric Bike with a large Wattage?

In the USA e-bikes have legal limits.  To be classified and electric bike Wattage must not be greater than 750 Watts and speed under power greater than 20mph

In Canada that limit on wattage is reduced in most States to 500W with some not specifying a numeric limit .

In Europe  & UK  where e-bike usage is  as much as 30 times that in the U.S, the limit is 250W which doesn’t appear to have impiared the growth of the market.

Of course you can convert your existing cycle to an e-bike when it appears all rules go out the window – check out this 1500 Watt Electric Bike

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