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e-Bike Buyer’s Guide

Words by Tony

on 28/10/2015 15:03:48

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e-Bikes come in as many shapes and sizes as non-powered bikes, so you can have an electric road bike, mountain bike, city bike or general hybrid style. But, there are extra choices for you to make as well, so this is a brief guide to choosing the e-Bike best suited to your needs.  For a more complete guide, please visit our Blog post on Choosing Your e-Bike.

Battery power, capacity and life

"How far can I go between charges?" is the most common question, and the answer is "It depends", but here are some useful guidelines. Firstly, you control how quickly you deplete the battery. e-Bikes have power assist settings that you use to control acceleration and the amount of assist. If you choose "economy", it will take longer to get up to speed, and your top-end speed will be lower than if you select "turbo" mode. In addition, most e-Bikes are pedal assist, so you need to turn the pedals, and the more force you put in, the less you consume the battery charge. Finally, hills consume more power than flats, so your route selection makes a difference. 

Watt hour calculationBatteries are rated in Watt hours (WH), and you can use this to compare the expected range between bikes. You simply multiply the voltage (V) by the amp hours (Ah) to calculate the Watt hours. On average, if you didn't pedal at all, each mile of flat travel will consume 15 WH. The e-Bikes we sell all have batteries with 300 - 400 WH, so that is 20 - 27 miles on a flat road with no pedalling.  Clearly, if you have to go up long hills you will use up the battery more quickly, but, if you use an “economy mode” of power and provide 1/2 the power you need by pedalling yourself, then you can extend the battery charge.

Batteries come in different cell qualities. Name brand cells such as Samsung, Panasonic and A123 will last longer (number of charge cycles)  than no-name Chinese cells. Of course if your pack consists of name brand cells, the cost per watt hour will be higher. A good rule of thumb on quality is the duration of the guarantee on the battery. Good batteries will have a 2 year guarantee, and less good ones will have a 1 year guarantee. If it’s less than that, you should just walk away.

 

Step-through versus CrossbarFrame design

The primary choice is whether there is a top tube or you have a step-through frame. If you have any limitations in your hip flexibility and find it hard to raise your leg around the back wheel and saddle, then a step-through frame will be the better option for you. Given e-Bikes are heavier than other bikes, a step-through is also easier to handle if you're not very strong.

Motor location and drive system

There are three primary positions for the drive system, the front wheel, the rear wheel and the crankset (to which the pedals are attached). By far the best  is the crankset, as it is the most efficient, and it keeps the centre of gravity low. Motors in the wheel hubs are more common, as they are less expensive, and there are offsetting pros & cons for front versus rear wheel. drive.

Throttle or Pedal-assist

Our FreeGo e-Bikes have a throttle, so you can choose to be powered exclusively by the electric motor. Our other e-Bikes are all pedal-assist, which means the motor amplifies your own pedalling. The amount of power added by the electric motor in all cases is controlled by the setting, for example "economy" or "turbo".

Cube stereo hybridMotor Power

As mentioned above, power is measured in Watts, so e-Bike motors will be classified as 250 watts, 400 watt, etc.  Of course, if you have 360 Wh of battery capacity and you are using your 400 watt motor at full power, then you’ll be out of charge in less than an hour!  To put this in perspective, a reasonably fit club cyclist would find it fairly hard to pedal at 250 watts for an hour, and Bradley Wiggins only generated 410 watts on average when he set the world hour record (34 miles), so 250 watts is a pretty powerful motor. Unless you need a very power electric mountain bike to help you power a heavy bike up mountain trails, it’s unnecessary to have more than a 250 watt motor.