GreenSceneEnergy presents:
Resources, Electric bike shopping guide.
So you’ve heard about eBikes and all of their great benefits. You’ve picked a great time to jump into the eBike craze. While technologies are still maturing and evolving, the current crop of product is reliable and affordable. There is a wide selection of eBikes and eBike kits available to get you the robotic riding partner of your dreams. But, how do you come to a decision on what to buy with all of the choices available? This guide will help you consider the options and come out with an eBike that you will love.
Shopping for an eBike can be intimidating because you suddenly need to decide on 2 things, a bike purchase and electronics purchase all at the same time. This guide will help you sort through the electronics portion of the decision. We have multiple guides to help you with the bicycle portion of the eBike on the site as well, so be sure to check those out.
The payoff for doing your homework is an eBike that fits you and your lifestyle. You’ll be riding more confidently and be more active. Riding with trained cyclists and Hauling a trailer full of kids will all be more manageable. An Electric Bike makes cycling better for the rest of us!
Getting Started:
Remember, an eBike is still mostly a bike. If you’ve been shopping for a bike recently you know there are a myriad of styles and price points to fit every need. So an excellent way to start shopping for an eBike is to figure out what kind of bike suits your purpose for riding and your personality. Once you have that in mind, it is time to start shopping for an electric version of that bike. Things like fit, handling, component quality and frame quality are just as important on an eBike as they are on their unassisted counterpart. The additional power of an ebike requires that you feel comfortable and in control of the machine since you’ll be riding further and faster than before.
Define your needs
After you’ve settled on a style of bike, ask yourself these questions:
What do I plan on using this eBike for?
How far do I plan on riding it in one outing?
What kind of terrain will I encounter?
Will I ride by myself or with friends on non electric bikes?
Analyze Yourself
Also, consider how many miles you might log per week, or year. And think about your tendencies in purchasing other things. For example, do you consistently demand the highest quality, or are you more apt to look for reasonable quality and lower cost? Do you dig trick, high-tech gadgets or are you satisfied with simpler designs? Additionally, it helps to know about how much you want to spend but be open to what is out there outside of your price range. Technologies vary greatly and you want to make sure your needs are being met.
Answering these questions will ensure that you get the best ebike. We'll be able to show you models with the right features for your needs, interests and budget. And you'll soon be sailing down the pavement with a big grin on your face.
Options, Options, Options
Not all ebikes are the same or created equal. Every eBike system has its own unique feel and style and will thus appeal to different riders. The only performance constant among eBikes is that they are all governed to 20mph, by law. (If they go faster, they are no longer considered bicycles and need to be registered) Everything else (weight, power, climbing ability, acceleration, control scheme) varies greatly from system to system. We really emphasize test riding before you buy to come to the best decision for you.
System Control
There are three major control types available currently: Throttle, Pedal Assist and Proportional Pedal Assist. All three ways get the job done but each definitely offers a unique ride Quality.
Throttle only systems are the most basic as they don’t integrate with the function of the bike. You’ll find both twist grip and lever style throttles on current eBikes. Modern throttles are variable, like a scooter throttle, and will allow for a nice range of power. They are a clean way to provide power on demand, but are an additional hand control. The majority of eBikes come with a throttle as primary control or as a backup to the primary control scheme.
Pedal Assist bikes go a step further by making the primary control the act of pedaling. When the rider starts pedaling the motor kicks in and starts assisting. Generally, you’ll be able to choose a power setting and the motor will engage based on that setting. Basic pedal assist bikes will give their full assistance when engaged. This can make them difficult to control at low speed, but also allows them to accelerate smoothly.
Proportional Pedal Assist, or pedelecs as they’re known in Europe, eBikes are the most sophisticated setups as they actually read how hard you pedal and base their assistance off of that measurement. These systems try to integrate with your natural pedaling for smooth intuitive control. These systems are the best at maintaining the bike riding sensation. Generally multiple power settings let you tailor the amount of work you want to do. Rider input is generally measured with a cadence or torque sensor. Torque sensors provide the most natural feeling. Pedelecs can feel “pulsey” if the software isn’t good, but generally offer the most seamless feeling of power.
Motor Location
Motor location also affects the ride quality of an eBike. It’s just as important of a consideration as control scheme and bike fit. There are three common placements for the motor and we discuss the pros and cons of each.
Drive Option –Front Motor
This is the Most Common option available currently. These tend to be the low cost option available. Beware of custom width motors. A fork failure could disable the whole bike due to lack of replacement availability.
Pros:
Cons:
Drive Option – Central Motor
This is the least common variation due to the requirement of a custom frame. The motor will deliver power through the bikes drivetrain allowing for improved efficiancy in some situations, but accellerating wear on the components.
Pros:
Cons:
Drive Option – Rear Motor
Rear hubs are becomming increasingly common because of their balanced ride charachteristic. They do limit drivetrain choice, but the benefits outway that minor limitation.
Pros:
Cons:
Motor Power
This is definitely the most confusing thing for shoppers. What does it mean to be a 250 watt motor? Part of the problem is that it can mean a couple different things. Electric motors are rated for a Peak (or maximum) wattage and a Nominal (power consumption at normal condition) wattage. Some companies list their peak, more common with bigger numbers, and some list their nominal rating. The further problem is that normal condition can vary from brand to brand so comparing nominal ratings isn’t always apples to apples. One more complication is that more wattage doesn’t necessarily mean more torque. Given the 20mph speed limit it is definitely possible to have 350w nominal motor that climbs and accelerates better than a 500w nominal motor and goes just as fast. Basically what all this means is that you shouldn’t be put off a system just because the listed motor wattage number isn’t what you are looking for and don’t just fall in love with a big number. We can help you get the whole picture and make an informed decision.
Motor Construction
There are two ways to build an electric motor, with or without brushes. The vast majority of eBikes are built with brushless motors for their high efficiency, no maintenance operation. Only the most inexpensive eBikes will use brushed motors.
So what is the difference?
A brushed motor uses physical contact between the moving and static parts of the motor to change the polarity of the electromagnet. The brushes that make the contact are subject to wear and are noticeably louder than brushless motors. These motors are also more susceptible to overheating that their brushless counter parts. Brushed motors are commonly used in power tools.
Brushless motors use a circuit board to deliver power to the electromagnet. No contact and no moving parts mean no maintenance. The added benefit of a brushless motor is the ability to run silently if it is well controlled. The circuitry required to run a brushless motor raises the price of the system but allows for the range of the bike to be maximized. Inexpensive brushless eBikes have a tendency to burn controllers under heavy loads due to the excessive power going through them. Consider how you’ll be using the ebike when making your decision.
Battery Choices
In today’s eBikes we have two choices for electricity storage, Lead Acid or Lithium Ion. Thankfully, Nickel based batteries have fallen out of favor for ebikes.
Lead Acid batteries are a low cost solution for carrying power on an ebike. Sealed Lead Acid (SLA) batteries are the most common type. The SLA can be encased in a housing without worry of an acid leak. While SLA’s are cheap, they have a comparably small number of recharge cycles and they become noticeably less powerful as they discharge, think of a flashlight dimming. SLAs also require a long charge time to replenish, typically 8 hours.
Lithium Ion batteries come in many varieties that balance capacity, volatility and performance. Thankfully eBike companies err on the side of safety when choosing their cell chemistry. Typically a Lion battery will charge in around 4 hours and have a fairly flat discharge curve, meaning the power feels fairly constant until it dies. Lithium cells are also locally recyclable at anywhere that sells tool batteries.
Range, Well that depends
This is where understanding how far you will ride is important. Most eBikes will have enough juice to cover your current riding habits. More capacity means your eBike will keep up with you as you start to ride more and more. However we want you to be able to separate the truth from the hype when it comes to the range question. Range claims are best guesses given certain conditions and everyone wants to state the longest they can, so it’s hard to know for sure how far it will go for you or is it? There is some quick math you can do to give yourself an accurate idea of an eBike’s minimum range.
First, how much power does the battery hold? We are looking for watt hours (Wh) here. Watt hours can be calculated if it isn’t given.
Watt hours (Wh) = Amp hours (Ah) x Voltage(V)
Then we take a look at the motor’s nominal rating. The normal condition for a nominal rating is generally 20mph, flat terrain, average size rider 160-180lbs. This is enough info for a good minimum range estimate.
Example. We have a 25V 10Ah battery and a 250watt motor.
25V x 10Ah = 250Wh
250Wh / 250W = 1hour
1 hour of operation at 20mph = 20 miles of range on the flat with an average rider.
Then you can fudge either way for terrain and weight. But now you have a baseline at least condition. Most customers end up right in between the claimed max range and the baseline condition for average range.
Kit or Complete
There are both complete eBike options available in addition to conversion kits. Essentially they are the same choice. With a complete bike, someone has selected the kit and the bike for you. If you go with a kit you have the control over the selection process. Both options have their pros and cons.
Complete Bikes have the unique advantage of being able to fully integrate the system into the bike design. Some systems are only available on complete bikes due to their design. The most common integration you’ll see is batteries internal to the frame, offering a clean look and a well protected battery pack. The downside of the complete is that it may not be exactly what you want or it’s unavailable in size to fit you. As more eBikes are sold the selection will improve, but it is nowhere near the selection of bikes we have available.
Kits are the best way to get the bike you want in its electric version. We will take a kit and install it on a brand new bike for and you have the complete electric bike, but in a combination of your choosing. That is the strength of the kit. The downside is that you lose the total integration and depending on the kit, it can look anywhere from original equipment to very home built.
Fixed or removable battery
This is a consideration that is often overlooked until you get your new electric bike home, where am I going to charge this thing? Batteries need to be charged often, usually after every use, but what if there is no power where you store your bike? Most chargers will have about 6 feet of reach, so if your bike lives 6 feet from an outlet, then you can have a permanently installed battery, if not you may only want to look at eBikes with removable batteries.
The other thing to consider is the temperature where you store your eBike. If the location routinely sees temperatures below freezing or above 110, then you’ll want to bring the battery inside. If it’s part of the frame, then you’ll be bringing the whole bike in. So take a moment to consider your storage situation.
Fixing a flat
eBikes that use hub motors are going to present a little more challenge for flat repair than a mid Drive system. If you decide to go with a hub driven system, ask about the electrical connections to the hub. They should be easily accessible, water resistant and not require additional tools to disconnect. Hub motors will be bolted onto the frame so you’ll need to carry a spanner in your flat kit.
Look for eBikes that have puncture resistant tires to prevent flats from happening in the first place.
Additional features
Regenerative Braking: All eBikes require the motor to cut out under braking, but more sophisticated systems will engage the motor as a brake. This feature will slightly extend the range of the eBike.
Lighting: If you’ll be riding at dusk or later, then lights are a lifesaver. Having the lighting integrated into the system means that you only have one battery to maintain.
Cyclo-computer: If you are interested in knowing how far a charge takes you, how fast you are going and how much you’ve been riding, then you’ll need a computer of some sort. Look for a system that integrates these features to reduce handlebar clutter.
Gear Hauling: You’ve got a motor now, so why not use your bike to carry some stuff? Look for a bike that has or is compatible with racks and baskets to make it a more useful tool.
May 26, 2012