E-bike Batteries and Motors: What You Need to Know

We’ve said it before and we’ll say it again: there’s nothing like the freedom and simplicity of bikes. The simplicity of two tires rolling on and on, scenery sliding by, tires crunching over gravel. We can’t get enough.

But when we discovered the pure fun and adventure of e-bikes, we dove all in without looking back. It’s all the fun and exercise of an analog bike with double, triple, or maybe even quadruple the ground covered. Who can argue that? Our transition from analog riders to pedal assist mountain bike riders was smooth but for one detail: learning all about e-bike batteries and e-bike motors.

Ask any bike manufacturer or retailer and they all might give you a slightly different answer about which motor is best, which battery has the longest life, and what you should choose. So here’s an intro to e-bike batteries and motors to get your head in the right space to make your own decision.

Which battery is best for an electric bike?

The one golden rule: lithium ion batteries far outperform everything else that’s realistically available today. While there’s promising early research showing that sodium-ion batteries could be the future’s battery of choice (even for smartphones and laptops in addition to e-bikes), the safe, time-tested choice for your new e-bike is a high-quality lithium ion battery with Panasonic cells like the QuietKat Jeep E-bike Battery.

Lithium Ion vs. Lead Acid Batteries

Chances are, if you’ve been doing your e-bike research, you’ve come across lead acid batteries as an alternative to the more ubiquitous (and notably more expensive) lithium ion battery.

The main problem: it’s extremely difficult to manufacture a safe, “sealed lead acid” or SLA battery that’s small and light enough to be compatible with the frame of your e-bike. Meaning, the most realistic solution is to mount it on a rear rack or place it in panniers on either side of the rear wheel. While this might fly in town or on pavement commutes, when we start talking about the balance, agility, and lighter weight needed to safely and successfully ride rockier, steeper trails, big, bulky battery packs are simply out of the picture.

How much is an e-bike battery?

The major benefit of a lithium ion battery for your e-bike, besides its better performance and ability to integrate into the frame of your bike, is your ability to easily carry an extra in your pack. On average, a high-quality battery can cost anywhere from $600 - $900 depending on the quality and amp hours.

Most new e-bikes (and all QuietKat E-bikes) come with a standard lithium ion battery that neatly clicks into the frame of your bike. But when you’re planning to cover some serious ground, take on lots of elevation gain, or camp in the middle of nowhere with nothing but what you can lash onto your bike (a personal favorite of ours), having an extra battery can make the difference between a successful ride out, or a full-on grind. In short: it’s worth the investment. Pro tip: all e-bikes are slightly different. Make sure your backup battery is designed to integrate with your particular frame.

Lastly, unfortunately e-bike batteries have become a target for thieves because of their high value and ease of transportation. Make sure you’re always keeping an eye on your e-bikes and our recommendation is to remove the battery before you lock your frame up outside in public.

So, you think you’re in the market for a backup battery, but first you want to know…

How long does an e-bike battery last?

Although there are confounding variables that affect the lifespan of an average lithium ion battery, like elevation gained, and conditions (it’s much harder to pedal through ice, snow, and mud, than it is to pedal over hard-packed, smooth dirt) it’s safe to assume that top-of-the-line, fully charged lithium ion battery like the QuietKat Apex 1500W Battery with 52V (volts) and 17.5AH (amp hours) can get you up to an additional 50 miles on your bike when in eco-mode and using pedal-assist.

And if you have an easier time understanding battery power in watt hours, simply multiply volts by amp hours. The above example, with 52V and 17.5AH gives you 910 watt hours.

Finally, let’s talk e-bike motors

The first time you ever hop on an e-bike and feel the motor kick in, propelling you forward and throwing your torso back is absolutely unforgettable. Here’s how it works:

Crack your motor open (we don’t recommend doing it—you’d completely ruin it—but it’s interesting to search on YouTube) and you’ll see the stator: a bunch of wires wound around a circular series of poles that becomes an electromagnet when current enters the motor controller from the battery.

You’ll also see a series of magnets near to or inside the stator. That’s the rotor. To completely simplify, the reaction caused by the interaction of the stator’s electromagnet and the magnets in the rotor—when current is introduced—is the sensation you feel when the e-bike lunges forward with your pedal stroke.

But, what does this mean for you? The principles stay the same, but not all e-bike motors are created equal. Take some time to do your research, digging up articles like this one to fully weigh your options before pulling the trigger.

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