How to Read E-Bike Specs: A Beginner's Guide to UL 2849 & Motor Watts

Your First E-Bike: A Mentor’s Guide to Decoding Specs for Safety & Fun

Let’s be honest: shopping for your first electric bike is confusing. You’re hit with a wall of jargon—terms like “UL 2849,” “Peak 750W,” “36 Volts,” and “281 Watt-hours.” It feels like you need an engineering degree just to avoid buying the wrong thing.

Most people focus on two questions: “How fast does it go?” and “How far does it go?”

As your guide, I’m going to tell you a secret: those are the wrong first questions.

The first and most important question you should ask is: “Is it safe?”

We’re going to walk through this together. Forget the high-pressure sales pitches. We’ll use a popular, entry-level bike, the Qlife Cityone, as our real-world classroom example. By the end of this guide, you’ll know how to read any e-bike spec sheet like a pro and understand the trade-offs between price, power, and, most importantly, safety.

Part 1: The Single Most Important Spec (It’s Not Speed)

In recent years, you’ve probably seen news headlines about e-bike battery fires. This isn’t a scare tactic; it’s a real-world problem caused by unregulated, poorly made battery systems.

This is where your new favorite term comes in: UL 2849.

If you remember only one thing from this guide, make it this.

What is UL 2849 Certification?

UL stands for Underwriters Laboratories, a global safety science company. The “2849” part is the specific standard for the entire electrical system of an e-bike.

This is a critical distinction. Many brands will say they have a “UL-certified battery.” That’s good, but it’s not enough. A safe battery can still be dangerous if connected to a cheap, untested charger or motor controller.

UL 2849 certification means the entire system—the battery pack, the charger, the motor controller, and even the wiring—has been rigorously tested as a complete unit. It’s been subjected to:

• Overcharging: What happens if you leave it plugged in?
• Vibration and Shock: Simulating rough roads and being dropped.
• Water Exposure: Testing for resistance to rain and puddles.
• Extreme Temperatures: Making sure it operates safely in hot and cold weather.
• Short Circuits: Ensuring it doesn’t catastrophically fail.

How to Apply This: The Qlife Cityone Example

When you look at the product details for the Qlife Cityone, one of the first things it mentions is “UL2849 Certified Built-in Removable Battery.”

This is what I call a “green flag.” It means the manufacturer invested the significant time and money (it’s an expensive process!) to have their whole system vetted. For a bike in the entry-level price range, this is especially impressive and should be a non-negotiable for you as a buyer.

Mentor’s Rule: Do not buy an e-bike in 2025 that is not, at minimum, UL 2849 certified.

Part 2: Decoding “Power” — Watts vs. Peak Watts

Okay, now that we’ve covered safety, let’s talk about the fun part: the motor. This is where most of the marketing confusion happens. You’ll see numbers like “500W” and “Peak 750W.” What’s the difference?

• Nominal Power (e.g., 500W): Think of this as the motor’s “cruising speed.” It’s the continuous power the motor can output for a long time without overheating. This is the number that often determines the legal “class” of the e-bike.
• Peak Power (e.g., 750W): This is the motor’s “sprint” power. It’s the maximum power the motor can deliver for short bursts, like when you’re accelerating from a stoplight or, more importantly, tackling a steep hill.

A car engine analogy: The nominal power is what you use to cruise on the highway. The peak power is what you use to merge into traffic or pass another car.

How to Apply This: The Qlife Cityone Example

The Cityone is listed with a “Peak 750W Motor” (and a 500W nominal wattage in its technical details).

This 500W/750W combination is a sweet spot for a city commuter. The 500W nominal power is more than enough for cruising on flat ground, while the 750W peak gives you that crucial “kick” to get up hills that would leave you defeated on a regular bike. You still have to pedal, but the motor amplifies your effort, making you feel superhuman.

Mentor’s Rule: Don’t just look at the peak number. A motor that’s “1000W Peak” but only “250W Nominal” might be all sprint and no endurance. Look for a healthy balance, and for city riding, a 500W/750W setup is fantastic.

Part 3: The “Gas Tank” — Understanding Your Real Range

This is the second-biggest area of misleading marketing. You’ll see claims like “Range up to 40 miles!” This is almost always a “best-case scenario”—a 120-pound rider on a perfectly flat surface with no wind, using the lowest possible pedal-assist level.

Let’s learn how to calculate the real gas tank size.

You need to find the Watt-hours (Wh). This is the true measure of battery capacity. If a listing doesn’t show it, you can often calculate it:

Volts (V) x Amp-hours (Ah) = Watt-hours (Wh)

• Volts (V): The “pressure” of the system. The Cityone uses a 36V system, which is common for budget-friendly e-bikes.
• Amp-hours (Ah): The “capacity” of the tank.
• Watt-hours (Wh): The “total energy” in the tank.

How to Apply This: The Qlife Cityone Example

The original article’s research found the key number: the Qlife Cityone’s battery is 281 Watt-hours (Wh).

Now, we can do some simple, real-world math.

A general rule of thumb for e-bikes is that you will use between 15-25 Wh per mile, depending on hills, your weight, and how much you use the throttle.

• Worst-Case (Heavy throttle, lots of hills): 281 Wh / 25 Wh-per-mile = 11.2 miles of range
• Best-Case (Low pedal assist, flat ground): 281 Wh / 15 Wh-per-mile = 18.7 miles of range

So, is the “40-mile” claim a lie? Not exactly. It’s possible if you’re barely using the motor (level 1 assist) and doing most of the work yourself. But for practical purposes, you should expect a reliable 12-20 miles of range.

This isn’t a bad thing! For its intended purpose—a city commuter—a 281Wh battery is a smart trade-off. It keeps the bike’s cost and weight down. A 12-20 mile range is more than enough for most daily commutes or running errands.

Mentor’s Rule: Ignore the “max range” claim. Find the Watt-hour (Wh) number. Divide it by 20 to get a realistic, conservative estimate of your range.

Part 4: The “Bike” Part — Frame, Tires, and Comfort

Power is fun, but you’re still riding a bicycle. The quality of the bike components determines whether you’ll actually enjoy the ride.

Frame

The Cityone uses an aluminum alloy frame. This is standard and it’s great. It’s much lighter than steel (which you’d find on very cheap bikes) and won’t rust.

Tires

The spec sheet lists 26” x 2.1” tires. This is another “green flag.” Many budget bikes use thinner 1.95” tires. That 2.1-inch width means the tire holds a larger volume of air. This extra air acts as a natural shock absorber, smoothing out bumps, potholes, and cracks in the pavement. It also provides a wider contact patch with the ground, giving you better stability and grip, especially in wet conditions.

Suspension & Brakes

It includes Front Suspension and Disc Brakes. At this price point, the suspension will be a basic coil fork, but it’s far better than no suspension at all. It will take the jarring impact off your wrists. Disc brakes (as opposed to old-fashioned rim brakes) provide much more reliable stopping power, especially in the rain.

Mentor’s Rule: The motor gets you going, but the tires, suspension, and brakes are what keep you comfortable and safe. Wider tires and disc brakes are major indicators of a well-thought-out commuter bike.

Your E-Bike Buyer’s Scorecard

You’re now equipped to look at any e-bike and understand what you’re really buying. When you shop, use this mental checklist:

• Safety (Non-Negotiable): Is the entire system (not just the battery) UL 2849 Certified? If not, walk away.
• Motor (The “Hill” Score): Does it have a Peak Wattage (like 750W) that’s higher than its Nominal Wattage (like 500W)? This means it’s built to help you with hills, not just cruise on flats.
• Battery (The “Real Range” Score): What is the Watt-hour (Wh) rating? (Calculate V x Ah if you have to). Divide that number by 20 to get a realistic range estimate and see if it fits your daily commute.
• Comfort (The “Enjoyment” Score): Does it have comfort features like wider tires (2.1” or more), front suspension, and disc brakes?

The Qlife Cityone is a solid example of a bike that gets these fundamentals right for its price: it prioritizes the UL 2849 safety certification, provides a capable 750W peak motor for city hills, and makes smart trade-offs with a smaller 281Wh battery to keep the price and weight manageable.

You’re no longer a beginner confused by jargon. You’re an informed buyer. Go find the bike that’s right for you.