learn about e-bikes

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Electric bicycles are essentially the summation and cooperation of three systems:

  1. Base bicycle

  2. Motor

  3. Battery

BASE BICYCLE

The majority of e-bikes are manufactured with the expressed purpose of being an electric bike; this means that the cables are housed internally (inside the frame), the motor, battery and controller more integrated into the frame for visual effect, and lighting married to the frame without having the add-on appearance. 

These bicycles come as they are, with a low ceiling for improvement. Customizing a pre-built electric bike can be an expensive proposition, because the manufacturer may not sell the ugrade you are looking for.

In contrast, custom-made electric bikes are an option that cost more up front, but in the process you can get exactly what you are looking for. This is what we refer to when talking about the "base bicycle." 

The base bicycle can really be any bike, old or brand new, high-tech or low. The technology on new bicycles can be amazing, incorporating carbon fiber and next-gen shifting and braking systems. For a custom build, we start by purchasing a ready-to-roll, non-electrified bicycle that has the specifications (size, tires, etc.) that are specified from our conversations with the customer. Alternatively, we can use a bike the customer already owns.

Sometimes on an electric bike, newer high-tech designs can be detrimental, depending on how much upkeep the owner would like to do. Electric bikes being what they are, the speeds and torques that are applied to the system are always going to increase maintenance time and cost. Therefore, sometimes perhaps a mid-grade frame is the best solution, in order to control the inevitable costs of owning and riding an e-bike. 

Additionally, carbon fiber can be hard to work with if we need to modify the bike frame to fit a certain component. The true value of carbon fiber frames lie in weight reduction (and some shock absorption), however on an e-bike frame weight is not a concern because of the inherent mass of the motor and battery, where grams of carbon weight savings are completely pointless. 

At Bonita Bikes we prefer the mid to low-end frames for our custom builds in order to decrease maintenance cost and increase part availability (which decreases the downtime on a bike repair). We just make sure that the derailleur and the gear system are adequate quality. 

Brakes

One key component on a bicycle is brakes, due to the faster speeds and higher weights of e-bikes. While we prefer to use a bicycle with disc brakes, rim brakes are just fine. We just caution the rider that they will not have nearly as much stopping power as disc brakes, and the upkeep will be slightly more, as rim brakes chew through the rubber much faster than the carbon brake pads on disc units.

 
 
 

BATTERY

In our view, the battery is the most important and most-overlooked factor in the e-bike experience. If your battery is not built to perform how you want, then you will never have the experience you are looking for.

If a battery is not built to output the power you need, or built with enough capacity to get you the distance you need to go (we do not brook range anxiety here at Bonita Bikes), then the whole experience is going to be a disappointment. 

A ride on an e-bike should be pure joy, and anything other is unacceptable. Many times, the battery is to blame. We will take you through an overview of how batteries are built, how to "talk" about them, and what you should look for when shopping for an e-bike or battery upgrade.

 

HOW BATTERIES ARE MEASURED

Battery voltage is the often the first measurement you will see on an e-bike, which we will explain below. However, when we talk about batteries, we're really most interested in talking about how "big" they are, which we can talk about (accurately) in two ways. Many times, you will see the "range" of an e-bike when looking at an advertisement. This is generally the best way to communicate the size of a battery to the general population, however is actually a completely irrelevant measurement. Range doesn't take into account how you ride, how much pedal assistance you use (the primary factor), the speeds you travel, how much pure throttle you use.... the list goes on.

Instead, we'll tell you how to expertly shop for a battery without relying on a nonsensical "range" number (which may just be made up in the advertising office anyway). We are after the hard specifications of capacity, which can be expressed in 2 units: Amp-hours and Watt-hours ...which are actually almost the same unit.

BATTERY CAPACITY

 

AMP-HOURS

We prefer to use amp-hours (which we will refer to now as Ah, such as 20 Ah), because the base unit of a battery (the individual cell, similar to a AA battery) is always measured in amp-hours. This measurement is simply how long a battery will output 1 amp of power. An amp is simply how much electricity is flowing per second.

 

 

 

 

 

 

 

 

 

 

 

As an example, a slow-moving e-bike will be consuming somewhere around 3-8 amps . If you have a hot-rod bike, you may pull up to 30 amps when accelerating or riding 25+ miles an hour.

Therefore, if you have a battery on your bike that is rated at 10 Ah, you can pull 10 amps for an hour. Understandably, to the average bike rider that still may be an expression that doesn't mean anything in the real world, as you don't have anything to compare it to. However, we can break the most common sizes of batteries down to something that a non-expert can easily understand, and which are usually advertised from reputable distributors or manufacturers: 

Small: 8-10 Ah

Medium: 12-14 Ah

Large: 15-18 Ah

XL: 19-21 Ah

Ludicrous: 28+ Ah

WATT-HOURS

We prefer to never mention watt-hours, because it can be a fairly meaningless number. A watt-hour is only the amp-hour measurement converted using the voltage your battery is nominally specified for.  Simply: amp-hours multiplied by voltage.  We feel that advertisers use the watt-hour measurement simply because it is a larger number than amp-hours, therefore tricking the uneducated shopper into thinking they are getting something they are most definitely not.

 

As an example, a medium-sized battery rated at 48 volts will be 624 watt-hours. However, watt-hours depend on the voltage of the battery, which changes as soon as you start riding. Voltage constantly drops as a battery is discharged, which happens to any battery, whether it is a Tesla or entry-level e-bike. Therefore, watt-hours is only a nominal measurement, whereas amp-hours is the actual measurement of the individual cells. This is why we prefer to use amp-hours to indicate battery capacity.

BATTERY VOLTAGE

The voltage of your e-bike battery is a critical factor, depending on what you plan on using your bike for, however this is a much easier unit of measurement to understand.  In most applications, you will choose either a 36 volt or 48 volt battery. There are other voltages, lower or higher, however they don't have a practical purpose other than specialty applications.

For an around-the-neighborhood rider, or perhaps an avid biker who is looking for a little extra assistance on a long journey while still doing a bit of pedaling themselves, a 36 volt (we will refer to voltage as now, such as 36v) battery is entirely sufficient. The voltage has no bearing on how far you can go.  Battery voltage only implies how fast  your bike can go, or how quick your bike can respond to you. 

For a commuter who does a daily work round, we recommend a 48v battery. Riding in traffic sometimes requires an extra dose of "pep" that a 36v battery cannot provide. For a mountain biker, trail rider, or even for hillier areas, we definitely recommend a 48v battery as well. A 48v battery will give you all the power you need to help get you negotiate your challenging environment.

A note on quality

Of course, quality is an important variable when purchasing a battery by itself, or a complete e-bike. Battery cells are much like car batteries, in that the individual quality vary to sometimes massive extremes. The cheap battery for your car that you may purchase at your big-box store WILL NOT last as long as the quality battery you buy at the specialized battery shop, such as an Interstate brand. The same goes for e-bike batteries. There are essentially four manufacturers of cells: LG, Sanyo, Samsung, and Panasonic. These manufacturers also sell their products to white-label companies that "re-wrap" the cells to make their own branded products (Queen Batttery, Hohm Tech, Molicel). The rest are either knock-offs, or are the discarded cells from these manufacturers that did not meet their exacting testing specifications. Bottom line is, if you do not see the brand of battery advertised, this means they are using discarded batteries that do not meet standards.

At Bonita Bikes, we know for a fact that our batteries are top of the line. When we build a battery from scratch, we only purchase name-brand cells from the noted manufacturers. We also have several shops that we source pre-built batteries from that also advertise these manufacturers. However, we choose to not be trusting, so we also do spot checks by disassembling the batteries they send us to make sure the batteries are built from the advertised components. Off-brand batteries are notably cheaper than name-brand units.

Why use the best battery cells?

We all know what happens when you are at the store looking at the display of AA batteries for your remote control. Duracell brand are much more expensive than the rest, and in the battery world there is a very good reason why. Li-Ion batteries are essentially a crapshoot to manufacture, and each cell must be tested to see whether it can hold up to the brand's quality specifications. When the cells fail, they are offloaded to second-hand distributors which are the brands you see at the dollar store or super cheaply elsewhere. Uncertified cells are not only a maintenance nightmare, but also actually dangerous. The reason why the cheap batteries in your remote control fail is because the cheap batteries can decide to give out at a moment's notice. When this happens in a massive battery pack for an e-bike, it can destroy the entire pack. Repairing a battery pack is often more expensive than just building a new one, as the cells are individually welded together into a large mechanism. 

We recommend only using cells that are of known quality to keep your bike running smoothly and keep you out of the repair shop.

MOTOR

 

The electric bike motor is easily the most variable component of the bike; motors are mostly Chinese manufacturers, with a few rare German or Swiss high-end units. There are some very gritty details to get into regarding the windings, gear ratios, heat dissipation, etc., however those are not discussions that any normal rider needs to worry about. We are happy to discuss more high-end details upon request.

The motor consists of the motor and controller (the controller is a piece of electronics that is often integrated into the motor housing).

The motor is the thing that actually turns the wheels, and the controller is the electronic unit that gives the motor the electricity it needs to turn the wheels. The controller takes input from your throttle or pedal-assist sensor (PAS), then gives the motor the right amount of energy to make you move depending on your request.

Mostly, when we discuss the motor, we just talk about how much power the motor can take from the battery and give to the wheels. The controller itself is a very important aspect, however most motors are supplied with the correct controller, so not much more thought need be given. Of course, there are always specialty applications, so the controller can be tuned and sourced differently according to those applications. 99.9% of the time, we'll just worry about the output specification of the motor itself. 

MOTOR SIZES

Generally speaking, there are 3 size ranges of motors:

1) 250-350 Watt

2) 500 Watt

3) 750 Watt

These are easily thought about as low, medium, and high power. Low and medium for the pleasure cruiser and exercise rider, and high power for the commuter/hill climber/trail rider.  Or, high power just for anybody who wants the extra pop or high speed available to them at any time. 

Motor Mystery: MID-DRIVE vs. HUB Motor

There are two types of motors: mid-drive and hub

One of these motors - hub - lives inside your wheel (front or rear), and the other (mid-drive) sits in the area where your pedals are. Both do the same thing (make your bike move), but they do it in very different ways. They are also built very differently and can help serve different purposes, depending on your biking needs.

In order to arrive at the correct choice for your motor, there are a number of ways to travel the decision tree:

Very, very serious bikers: mid-drive

Hilly areas or mountain bikers: mid-drive

Around the neighborhood: HUB

Small easy commutes: HUB, probably

Longer commutes (high speed and also good acceleration): mid-drive

Unsure? The following may help out.

How they are built:

Mid-drive motors do what you do: they turn the chain which drives the back wheel

Hub motors turn the wheel on their own, which is why they can be inside of the wheel and be in the front or back

MID-DRIVE

Mid-drive motors are usually more expensive, for the simple reason that they exist to serve the more serious of the electric bike crowd. Most manufacturers make mid-drive motors in higher power-output models, therefore are more expensive due to the nature of the power-handling capacity of the components. 

There are less varieties of mid-drive motors than hub, of which the most popular of which is Bafang, an extremely reliable manufacturer. At Bonita Bikes we HIGHLY recommend Bafang motors, as they have served us unbelievably well over the years. Of course, they are not the only good motor company, however anything with a Bafang motor will be highly regarded by us.

HUB

These motors can be found in a variety of sizes, let's boil down the most normal ranges:

(Measurements in Watts, unit of electrical power)

250 - small

500 - medium

750 - large

1000 and above - probably not for you if you are reading this 

Most e-bikes you see will probably have a hub motor, as they are the cheapest and easiest to install, requiring the fewest components for the consumer and the manufacturer. One additional benefit to hub motors is that they are the only motors that may offer regenerative braking capability (using your motor to brake the bike instead of traditional mechanical brake pads). You gain a very slight battery charge from the regen systems, as well as saving on brake maintenance. 

HUB MOTORS: Direct Drive vs. Geared

Direct drive motors are the cheapest, and can provide the most power -- they are also the only motor that can be used for regenerative braking

Geared motors are a little more expensive, have a lower maximum power threshold, and do not offer brake regen. However, they are more efficient and give the rider a much more ideal low-speed response, as the motor is geared to turn much faster and provide more torque at lower powers.  The lower-speed biker will appreciate a geared motor much more than a direct-drive system.

In general, an average rider should not be concerned about the power output discrepancy between direct-drive and geared motors. Only to the high-performance, high speed rider will this difference become an issue.

Additionally, regenerative braking is not something that should concern the average biker, because the real advantages of regen only become apparent for long distances and braking from high speeds, frequently.

Direct-drive motors also have the added drawback of having resistance to pedaling -- if you turn your motor off, you will be pedaling to both make the wheel turn, but fighting the resistance of the motor (which is why it can give you regenerative braking).

 

Geared motors "freewheel," which means the wheel spins freely even when the motor is not providing power. This can be very helpful to bikers that run out of battery juice, or else who may simply want to have the option to pedal the bike on their own power for fun.

The large majority of bikes for sale on the internet or in the shops offer direct-drive motors, because they are much cheaper to manufacture, and are a little more reliable (less moving parts from not having gears). At Bonita Bikes we do not say they are bad, however if we are doing a custom build with a hub motor, we will generally gravitate toward a geared option, depending on the purchaser's price direction, and riding needs. We have built super-high performance bikes with direct-drive motors, with speeds up to 35 mph, and also cheaper models for the neighborhood cruiser with both options.

Wrap-Up

In the end, there are many factors at play when looking for an e-bike, whether it be off the shelf, or custom-built. 

Do not let this discourage you!

 

Since you have read this article, you already know more than most consumers about what you are shopping for. Armed with a little knowledge, you can go out and find the best bike for yourself. We can also help you find the best bike for your needs, as a consulting service. The best option may also be to start a dialogue with us, dial in what your riding needs are, and have us build a custom bike for you, making it all your own, as well as being easily maintainable. We are happy to help with anything!

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