Ebike battery – How to make sure that you have the best. Homemade ebike battery

Ebike battery – How to make sure that you have the best

The best ebike battery is constructed using brand name 18650 Li-ion cells with an individual rating of no more than 38000 mAh. It is essential that the battery pack has a high quality Battery Management System (BMS). It is best practice to use 18650 cells which have additional protection circuits built into the cell. Additional padding inside the battery pack can help absorb jolts and, if used properly, can increase airflow to help dissipate heat. There are a few variations of Li-ion chemistry, however, this is rarely specified by manufacturers who use the umbrella brand of Li-ion for all 18650 cell variants.

Cheap Li-ION ebike batteries

Cheap Li-ION ebike batteries cost less than a tenth of the price of brand name batteries of the same capacity. A common 36 volt, 10AH Li-ION battery pack sells for around US300 on Amazon where similar capacity batteries for brand name electric bikes are over 3000. Here’s the thing There is a trade off between quality and economy. Low cost replacement batteries are cheap for a reason. There are a number of issues with cheap ebike batteries: They are unreliable, frequently constructed incorrectly, rarely meet their claimed capacity rating, and are often dangerous. Despite the drawbacks, the relatively low cost of cheap batteries is compelling as brand name replacements are beyond the budget of most ebike owners. This raises the question:

Which batteries are best for ebikes?

For the past 20 years, the best ebike batteries have used Li-ion 18650 cells. Li-ion has dominated as the best technology and advancing chemistry continues to increase capacity and reliability. Li-ion provides the highest power for size. It is reliable, light and cost effective.

For the next few years, the electric vehicle world will continue to use Li-ion chemistry and Li-ion continues to be the best option for most electric bicycles.

If you want maximum power for your dollar then lead acid batteries are the best option. The issue with lead acid batteries is that they are over 4 times the weight of Li-ion equivalents. For electric bikes, the extra weight of lead acid batteries is a problem for most riders.

Many alternative battery chemistries have shown promise over the years. Lithium polymer (LiPo), Nickel metal hydride (NiMH), and Lithium Ferrous (LiFe) have all tried and failed to better Li-ion.

There is, however, massive investment in a range of new technologies which extend the range that electric vehicles can travel before requiring a recharge. The most promising technology that is beginning to emerge is rechargeable hydrogen cells. [click here to read our article on ebike batteries using hydrogen cell technology]

Rechargeable hydrogen cells are available now although they are in an early phase of production. In 2021, this very new form of powering electric bikes is beginning to roll out in Australia. Hydrogen cells for electric bikes would be expected to reach Europe and the US in 2022 if the technology proves to be successful.

As the roll out of cost effective hydrogen cells is new to the market, it is still too early to say whether they will begin a revolution in powering electric vehicles.

Ebike battery replacement

Once you have coughed up the substantial investment required to purchase your e bike, you typically have a year or two of good use before the battery supplied with the bike begins to fail. If you can afford a brand name ebike, you would typically expect the battery to last two to three years before the travel distance becomes annoyingly short.

It is a shock to most e-bike owners that replacement batteries for most ebikes can be more than half the price of a replacement bike with the latest battery fitted. In addition, the Rapid re-design of ebikes often means that it is difficult to obtain a replacement battery that fits your model bike.

When the battery dies, ebike owners are forced to seek a low cost replacement, or scrap the bike completely. The problem is that a good replacement battery by itself can cost as much as the e-bike with the battery included.

a) Battery Management Systems (BMS)

BMSs protect Li-ion battery packs from a range of potentially damaging issues. Batteries can be damaged if they are overcharged, drained excessively, discharged too quickly or if they overheat. BMSs ensure that the individual cells within the battery pack operate within their specified limits.

There are 2 types of BMS. The most important BMS is an overall management unit which manages all the individual cells within the battery pack. Each battery cell within the larger battery pack can also have individual protection circuits.

Battery cells with individual battery protection circuits can help to further protect each cell. They provide secondary protection if the main BMS is not providing sufficient protection for the cell.

Low cost batteries seldom use secondary protection within the cell as they are usually more costly and have a slight drain on the power of the cell. Ultimately, secondary protection within the individual battery cells is not necessary as the main BMS should provide good protection.

Low cost ebike battery packs use triple layer Printed Circuit Boards (PCBs) which are more prone to failure and cannot be cost-effectively repaired. Production line experts advise that triple layer PCBs have between 30-40% failure rate on leaving the assembly line due to warping effects.

Three layer PCBs offer a small cost saving over 4 layer technology but when price is of prime importance, reliability suffers.

China is the world’s largest manufacturer of cheap ebike batteries. Multiple layer PCB’s (4 layer or 2 layer) are more reliable but are difficult to source and are not produced in the same quantities in Chinese factories.

The greater complexity of 4 layer PCBs make them more expensive to design and produce. In addition, although 2 layer PCBs are usually cheaper, the circuit boards are larger and heavier than PCBs with more layers. As 2 layer BMS are not as popular in Chinese manufacture they are not in the same volume and, therefore, are more expensive.

In addition, the technology of poor quality PCBs can have an effect on the reliability of battery packs. Higher price PCBs can provide smarter cell maintenance to reduce the power supplied by the battery to better protect the individual cells in the battery pack from damage. Similarly, more expensive BMSs can protect individual cells from overcharging and overheating.

Re-cells the e-bike battery

Adjusting the battery of the electric bike, i.e. replacing the battery cells! Making cells is clearly cheaper than a new battery. By repairing the old you will also save the environment.

We make cell cells for electric wheels, contact us and find out how your old battery can be saved!

Contact us by email info @ proakku.fi

When sending the battery, be sure to bring the charger! Why? Here are three reasons:

We check the performance of your charger – sometimes the battery malfunctions are caused by the charger used and does not fully charge the battery, for example.

After work, we will make sure that the battery is charged correctly and fully charged with your charger. After that, we can see the outcome of the work, i.e. what the power of the sensor was your aability to do.

This is all included in the job price!

Not in stock, only as backorder

Tuotetunnus (SKU): sahkopyora-akun-kennotus Osasto: Akkujen kennottaminen Avainsanat tuotteelle kennottaminen, kennotus, sähköpyörän akku


The re-celling of a battery of the electric bike saves money and nature! Replacing the new battery cells is a cheaper way to get the wheels rolling again. The battery usually dies in winter because its voltage drops too low (less than 2.5V in the battery).

Batteries for use in electric wheels

In Finland, almost all e-bike batteries use li-ion or li-po battery cells. The advantage of lithium batteries is light weight and high capacity and power supply in relation to the size of the battery. The weakness of lithium batteries is sensitivity to overcharging or undercharging. For example, the battery cell 18650 li-ion, which is the most used battery cell for electric bikes, requires a charge of 2.5V to 4.2V. Therefore, aBMS (Battery Management System) (Battery Management System) has been added to the battery packs.

The function of the BMS is to monitor the cells in the battery pack and to interrupt the discharge or charge when the battery reaches the programmed voltage level. Due to bms, lithium batteries are quite simple because the cyclist does not have to measure the battery charge, but the BMS stops the power supply. Thus, the battery runs out before it reaches dangerously low voltage. So it’s the same as on the phone. The phone reports a battery charge of 0%, but in reality the battery still has power to prevent deep discharge from damaging it.

Probattery tips for maintaining the battery of an electric bike:

  • Do not disassemble the battery too empty! If possible, do not disassemble the battery in less than 20% of the charge. The lithium battery starts to oxidize in too low a charge. Keep the battery in a 60-80% charge, especially when storing. In winter, it is a good idea to charge the battery every three months.
  • If the battery is hot, allow it to cool down before charging. The battery may warm up when discharged with high current. Heat is especially the enemy of the li-po battery. Battery chemistry stays smoother and in good condition for longer if you do not charge the battery when it is hot.
  • Keep the battery close to room temperature. The frosty winter in Finland absorbs the juices from the batteries if the battery is left cold. Similarly, temperatures above 40ºC over time interfere with chemical reactions in the battery. Take the battery in for the winter and in the summer store in the shade.

How long does the e-bike battery last?

The cyclist’s driving style affects the life of the battery. Hard accelerations require more power from the battery. The lithium battery can withstand about 500 recharges. This can be greatly reduced if the battery is constantly discharged with high currents. Some wheels prioritize the range and battery age by limiting the battery output.

Lithium battery performance is always a compromise between capacity and power supply. The maximum capacity of the 18650 battery is practically 3500mAh or 3.5Ah. The maximum power is approximately 35 amps from a battery cell of that size. However, these features can never be obtained in the same battery cell.

A high range is obtained by selecting a high-capacity battery sensor, such as Samsung 35E or LG MJ1. These 18650 batteries offer 3.5 Ah capacity, but the maximum discharge current is only 10 amps. If you want more power off your bike, you can choose between high discharge battery cells such as the Sony VTC5A or Molicell P26. These batteries have only 2.6Ah capacity, but a wild 35A power supply.

Of course, by connecting the batteries in the chest and series, you can get more familiar readings, such as 36V and 418Wh. Well, what do we just talk about amps and now all of a sudden watt lessons?

The Shimano BT-E6000 e-bike battery is powered by 18650 li-ion cells with a rated voltage of 3.6V. It can therefore be calculated that the battery is connected in a series of 10 batteries. 36V / 3,6V = 10.

The amps are obtained by dividing the wattage hours by voltage, i.e. volts. 418Wh / 36V = 11,61 Ah. Then, when it is known that shimano’s battery has 40 cells, 11.61Ah can be divided by four. Four because we already know that there are 10 batteries in a row, so in parallel 10 sticks there are four.

11,61Ah / 4 parallel connections = 2,9 Ah. So we know that the battery uses 40 pcs of 18650 batteries with a capacity of 2900mAh.

This is a good idea to know if you’re wondering which battery cells you’d use to update your e-bike battery.

What should I take into account in the battery of an electric bike?

The e-bike battery package can be built according to the user’s needs using high-capacity cells or high discharge cells. The most common need is to maximize travel, meaning we usually put LG MJ1 18650 cellsto provide 3.5Ah capacity per sensor. Another excellent, slightly cooler option is the Panasonic-Sanyo NCR18650GA 18650 battery cell,3.5Ah capacity and 10A discharge.

The lithium battery possible bms is also the hardest element in the battery. The BMS charge control circuits from the manufacturer have pre-programmed in-control. It involves not only monitoring battery performance, but also discussion sup with the bike management system. For example, the battery tells information about its charge to the bike’s driving computer, which requires much more complex programming. Of course, e-bike manufacturers do not sell separately BMS circuits, but directly from new batteries.

BMS is the biggest challenge for the do-it-yourself construction. The battery pack may keep the battery dead if it has been empty for a long time. Even if the cells are loaded separately back into a good reserve, the programming of BMS cannot usually be changed at home. In this case, you will need to buy a new battery or put in a generic bulkkiBMS that monitors the battery cells, but does not know how to do anything else. Then the electric bike can run on an old battery, but it no longer knows the same tricks as the original.

Do-it-yourself e-bike battery

Only BMS status is an obstacle to those who are handy with their hands. If the BMS is very awake in the battery, but the battery cells are tired, the cells can be replaced.

Here’s a good example for english speakers in the video:

ebike, battery, make, sure, best

The video makes 13S2P, or 13 cells in series, 2 parallel battery packs. It uses Samsung INR18650-25R 18650 battery cellsthat provide 20A continuous discharge current and 2.5Ah capacity. The parallel connection of two cell lines means 5Ah capacity and 40A discharge current in the battery pack. 13 cells in a stick, i.e. when connected in series, make the battery pack 13x 3.6V = 46 V.

What does it take to get a battery?

When building the battery pack, the battery cells must be as close as possible to each other. In the worst case, if the battery has a high voltage difference, you can build a battery that has not worked.

Connecting the batteries into a battery pack is done by spot welding. Spot welding is practically the only working way, as knocking heats the battery too much and at worst spoils the entire cell.

Spot welding supplies electrical current to the welding site, which provides the heat required by the weld. The result is a very neat welding result and the battery cell remains intact.

For more information on how to design and build your battery, see https://www.instructables.com/ID/DIY-EBike-Battery-Pack/ Visit at least check out the images.

Custom-made e-bike battery

If your battery is running out of time, you can also send it to us. We’re analyzing the potential for that condition and re-encapitsion. After the measurements, we agreed with the customer which direction to go with the project. We can order any battery cell from the battery pack, including the new 20700 and 21700 battery cells.

The cost of work consists of battery cells and work done. Depending on the complexity of the battery, the work can cost 150-200 euros. As a result, we’ll send back a battery that probably has better features than original ones. (No need to use the most cheap cells, so you can maximize, for example, the capacity of the battery size within the limits allowed.)

The cells of the e-bike batteries depend a lot on the battery structure and desired features, so please contact us by email info @ proakku.fi

At least the battery model and preferably a picture of the battery should be attached to the message. Let’s build the batteries that are right for you!

ebike, battery, make, sure, best

You can send the battery to:

  • Jesi Verkkokaupat Oy
  • Pääskynlento 13 B 43
  • 20610 Turku, Finland
  • 045 263 8565
  • Don’t forget to bring the charger!

The Ultimate Starter Guide to DIY Ebike

Electric bikes gradually replaces traditional and regular bikes. They are not only efficient but also premium with sleek designs. Since it’s becoming a trend in society, an individual needs to understand the concept of DIY Ebike. Sometimes, users decide to update their existing traditional Ebike into the electrical mode. However, a user needs the best e-bike conversion kit to achieve this purpose. A user also needs to choose the right bike. It will be unrealistic to pick any random motorcycle in your garage with the hope of achieving a premium electric bike. The bike shop in your residence should be able to recommend the best option for you.

The fundamental concept of the DIY Ebike is to curb the high rate of electric bicycles. Users can beat the traffic at a lesser cost using a DIY e-bike kit. This article contains information about electric bike conversion kits and other related exciting topics for the readers.

Choosing the Best Battery for Your DIY Ebike

An electric bike’s battery is one of the critical features you need to develop a DIY e-bike. Electric bikes operate on electrical energy against the traditional means of commuting with fossil fuel. Hence, the battery serves as an energy reservoir for this transport mode. Meanwhile, a battery determines the rider’s maximum speed, voltage, and riding capacity.

Your battery capacity describes how far you can travel before it runs out. If your battery capacity is high, a rider can cover a longer distance and vice versa. However, some factors may influence the distance level, such as weather conditions, support, and body size. Most electric bikes with high battery capacity are usually more expensive than those with low battery capacity. Nevertheless, Haidong has several battery capacity ranges that suit many users’ preferences.

An electric bike with a high voltage rate also yields massive motor operation and power. Several users request different voltages, depending on the ride’s intended purpose. For instance, the required voltage for rough terrain will vary from a south road. Meanwhile, experts and experienced riders opt for high voltage e-bikes for driving on rough terrains. Other factors to consider in choosing a suitable battery for a DIY e-bike are highlighted below.

Understanding the basic battery parameters, bearing in mind your requirements, financial capacity, and taste.

Communicate effectively with your battery provider and in more explicit terms for every product or kit agreement.

Ask yourself the maximum weight of the electric bike.

Installing Motor in your Bike System

There are popular motor types in electric bikes: the rear hub, front hub, and mid-drive motor. It would help if you altered the front wheel of an e-bike to use the front motor. Users with rear hub motors put the motor in the middle, alternating the rear wheel position. Also, a mid-drive motor has the pedal assist function, with the motor located at the bottom of it. Each of these motors serves a distinct function. They all have pros and cons, while a user is in the best position to make a choice or preference.

The mid-drive motor is often popular among DIY e-bike enthusiasts. They are user-friendly because they allow riders to adjust their speed and torque appropriately. It is also the best option for a rider who wants to go uphill. Meanwhile, hub motors are cheaper than mid-drive motors. An average engineer can try the hun motor drive, especially riding downhills.

Assembling your Electric Bike Kits

Assembling electric bike kits has its challenges, except you have studied the engineering input. Hence, it will become easy at this point. The start phase will require you to put the inner tube and tire at the rear wheel. These components are usually removed from the hub motor wheel. Slowly screw them to the electric bike motor to prevent the elements from threading. If you have trouble aligning your motor unit to the disc brake, adjust them properly before continuing. This is a DIY e-bike strategy you should be cautious of.

If your kit already marked the torque arms as the left and right positions, fix them into the axle nuts. It may take about ten minutes, then set the controller upright. If the pedal is immediately above the down tube, it may not be easy to notice it. After successfully fixing the controller, return the electric bike to its previous position. Afterwards, place the e-bike upright and let the tires support its weight. Then, go ahead to include the e-bike battery.

Implement basic engineering skills while fixing the battery, especially if the mounting plate holes do not align with the bottle bolts. Hence, draw small holes in this frame region, where the screws can fit perfectly. The best solution is to replace the shock so that the battery can fit in. Hence, this will not require a shock replacement. In most cases, a 21’’ frame is compatible and ideal for most electric bike systems.

The next assembling tool for your DIY e-bike is the cycle analyst meter. Make sure the handlebars can accommodate the cycle analyst meter. Also, the throttle assembly should fit into the right handlebar appropriately. The bottom bracket will bear the pedal-assist function, considering it’s a DIY e-bike. Wherein pedal-assist is also based on users’ choice. After setting these, assemble all the cable wires. Connect the cables to the controller, following each unique size and location. You can try cable wires for a neatly done connection.

The Step-by-Step Procedures

Beyond batteries and motors, other features contribute to the conversion success rate. Any slight fault from these features is powerful enough to affect the overall performance. The best bikes are categorized by their features, performance, and effectiveness. An e-bike conversion kit often has an installation manual. However, this guide provides the step-to-step process of installing your electric bike kit.

Step One

Many users make a mistake by starting the bike without prior testing. You want to make sure the needed materials are complete. Even though having a complete package will attract an extra fee, it is the best caution step.

Step Two

The best step is to install your motor unto the machine. However, the installation procedure will be determined by the rider’s type of motor. Also, check that the brake is in good shape and fix the speed controller and accessories to the e-bike frame.

Step Three

The three key features at this stage are the throttle, battery, and speed controller. When these three are appropriately connected, your e-bike will operate without interruption. Also, make sure to use the proper cables to prevent any fire outbreak or spark.

Step Four

The handlebar region is the spot for an electric bike display. This is where you see activities with the e-bike, such as the speed. Unscrew the display region, and tighten it back.

Step Five

A throttle should be connected to the brake lever. However, some DIY e-bike enthusiasts only fix the throttle to the brake level already. The ignition button will prove if you have done an excellent job or not. When an individual uses the switch button, the battery will be ignited, and the cycle analyst meter will light up. However, ensure the battery is fully charged before riding your bike into the cities.

Top Challenges while Assembling E-bike Kits

One of the main challenges people have is removing the shifter. Meanwhile, this can be quickly done when you have removed the handlebar. This can be time-consuming, so you need to use premium tools only. Also, make sure every other thing is in order before fixing the handlebar. A pretty tricky handlebars grip can be removed with water instead of oily spray. This will stop the substance from messing up the whole process.

Another challenge is installing the bottom bracket shell with the whole system, even though the diameter is compatible with the system. New bikes often have little pieces of metal at the bottom bracket. The solution is to identify if they are any metal stuck in the shell. When the bottom bracket area is free of anything that could stand in the way, you shall overcome these challenges.

ebike, battery, make, sure, best


If you have been thinking of investing in transportation, maximize the advantages of DIY e-bikes. Both cyclists and random riders are saved from the high of electric bike features. This is most especially common for mountain bikes. You can still enjoy the benefits of electric bikes without losing the attachment to your regular bike. Also, many young people find it attractive to convert their pedal bikes to electric bikes. This mainly applies when they live in a dense urban area.

Once you have the basic technical and electrical skills, you can easily add conversion kits to your bike. Ensure the electric bike conversion kit has everything you may need, and follow the instructions stated above in this article. However, make sure to run your DIY ebike in a less congested area before going into the cities. You can quickly identify any error or fault in the installation process and fix it up.

You Can Build an Ebike. Yes, You.

Just like regular bikes, electric bikes experienced a pandemic boom, giving more people an alternative way of commuting, picking up the kids, or just getting outside. But you might already have a functioning bike and wonder if you need to invest in (or make room for) another. If you’re willing to put in some light to medium work, you might not have to. How do I know? Let me tell you—I’ve done it myself.

My wife likes to commute by bike to her job in Washington, DC. There’s just one obstacle: Capitol Hill. Not legislation, but the actual, elevated land feature. It’s no Colorado mountain, but it is a challenge, especially when she’s hauling work gear on a swampy day.

I, a bike nerd, leapt at the chance to draft her into the ebike brigade. But my local shop had maxed out its waitlist months before. Even if I could find an ebike, we’re apartment dwellers, and our building’s bike-storage area only has so much room. We would have to choose, it seemed, between her familiar 1990s hybrid or a new purchase.

Or, it turned out, I could just make an ebike.

I could replace a wheel or the bottom bracket of my wife’s bike, run some cables with Velcro and zip ties, and attach a battery. True, the task requires moderate research, light to medium wrenching, and variable fiddling. But if that sounds like a good trade to get some lithium-ion pedal power, let’s go over how to add some DIY range or hill power to your own bike.

Where should the motor go on your bike?

Ebike conversion kits come in three main kinds, which I’ll list from least to most complex in terms of installation:

  • Front hub (shown above): This process entails swapping in a new front wheel with a motor at its center.
  • Rear hub: You make a similar swap, but for your rear wheel (in addition to a new freewheel or cassette cogs).
  • Mid-drive: You install a motor beneath your pedals (in your bike’s bottom bracket).

Each setup has its pros and cons (see the tables below). The more you know about your bike, and how hilly and far your typical ride will be, the easier your choice will be. The hard part is forecasting how much power and range you’ll want once you’re into ebiking, said Adam Ostlund, managing partner at Electrify Bike Co., an ebike seller and shop in Utah. Ostlund gets customers saying that they haven’t ridden in 20 years, and that they only want to take weekend rides with their spouse—but a year later, they’ve hit 3,000 miles and want upgrades. “Once someone starts riding ebikes, they’re always going to want more. So we try to start them at ‘more,’ so they don’t regret it later,” he said.

Front hubs

Pro Con
Easiest install Torque arms—additional metal bracing to secure the axle in the bike’s frame—advised for more than 250 watts, complicating flats and repairs
”All-wheel drive” (when also pedaling) on flat roads Less traction on steep hills and poor road conditions
Lower cost than rear hubs or mid-drives Easier to overheat motor on hills or spin-outs
battery-placement options (using smaller batteries) Trickier handling and balance for inexperienced bikers
Discreet look thanks to a smaller motor Limited in power (500 watts or less recommended, especially with aluminum or carbon forks)

Rear hubs

Pro Con
Easier install than mid-drives Changing tires becomes more inconvenient
Better weight balance and traction for hills and rain Larger motors make heavier bikes
Higher power ranges available Torque arms needed for higher wattages
Fits bikes with irregular bottom brackets Drivetrain and wheel components may be cheaper quality than original bike parts


Pro Con
Allows you to use your bike’s gears to shift between torque and speed Faster drivetrain wear
Better weight distribution Less clearance under the bike
safe power configurations Best to avoid shifting while motor is engaged
Better for mountain/trail/hill riding intensive install with specialty tools (and sometimes frustrating bottom-bracket sizes)

Most DIY ebike enthusiasts prefer mid-drive motors, which leverage the bike’s gears to alternate torque and speed, unlike the blunt push of motorized hubs. They’re generally safer for your bike’s frame, especially with newer bikes made of aluminum, carbon, or alloys instead of older, tougher steel. They make more efficient use of battery power, especially on hills. And a mid-drive motor’s weight sits evenly in the middle of the frame, rather than at the front or back. If you’re planning to tackle hilly trails, off-road conditions, or long ranges, a mid-drive setup is definitely best.

But hub motors have their place. They start at lower than mid-drives. They’re notably easier to install than mid-drives, and they let you avoid dealing with installing a motor into your bottom bracket—a bike part that can be notoriously varied in kind and size. Hub motors are a decent choice for commuting on paved streets with light to medium hills, when you’ll be using your legs most or all of the way. Just make sure that you brace your bike frame properly.

How will you control the motor?

Your decision depends on what kind of riding you do. Most kits offer three main ways to control how much power your bike’s motor supplies and when: a throttle, a cadence sensor, or a torque sensor. Some bike kits include both a throttle and a sensor for your choice or combination.

A throttle is what it sounds like: a button, lever, or handlebar twist that lets the rider manually apply power with no need to pedal. Throttle riding is what you see delivery riders using in major cities. It uses a lot more power. It’s also a useful backup if the bike, or the rider, starts to fail during a ride.

A cadence sensor turns your motor on when you are pedaling and off when you stop, increasing its output the faster you pedal. It’s usually paired with a kind of shifter for the rider to choose the level of assist (you’ll see this system on most shared city ebikes). It’s more hands-free than a throttle, but it can be a bit awkward in low-speed situations, such as when you’re starting from an intersection.

A torque sensor gives you more power when you’re pressing harder on the pedals, whether you’re climbing a hill or pushing for speed. Torque sensors feel the most natural—they push hard when you push hard—but require more work to install and maintain.

How much power and battery do you need?

Once you’ve chosen a kind of motor, you decide how much motor you want, as well as how much battery you want behind it. Motors have watt ratings, batteries have voltage and amp-hours—it’s a dense thicket for a newcomer. Micah Toll, an engineer who writes at EbikeSchool.com and Electrek, helped me FOCUS on what matters.

First lesson: Ebike motor ratings are mostly nonsense. Some countries cap ebike motors: 250 watts in much of Europe, 750 watts in much of the US. Not coincidentally, motor makers and sellers advertise a motor’s “continuous” power instead of its peak rate. The more clear way to compare ebikes is to look at the voltage and current (amperage) for hill-climbing and top-speed power and to consider watt-hours for battery longevity.

You can tweak the voltage and current with different battery controllers, gaining more speed, more hill power, or different assist levels. The power you need depends on a lot of factors, including your body weight, the bike’s weight, and your pedaling power. Bicycling magazine has a deep dive on how to understand ebike motors and power (presented by Bosch, which makes its own ebike motors). Generally, Toll suggests, 24- and 36-volt setups are for casual riders who plan to pedal a good deal and don’t face lots of hills, while setups at 48 volts and above are useful for hills and no-pedal throttle riding.

I went (very) small for my wife’s roughly 650 ebike kit from a company called Leeds: a 250-watt, front-hub motor, powered by a 24-volt battery with 5.2 amp-hours, roughly the size of a squared-off 16-ounce beverage can. But watt-hours (Wh) offer a better battery comparison than amp-hours (Ah) do. You get watt-hours by multiplying the battery’s voltage (in this case, 24) by its amp-hours (5.2), so for my wife’s kit, that works out to about 125 Wh. Technically that means her fully charged battery can run her 250-watt motor at full power for about half an hour. It’s a useful comparison, but ebikes pull “full power” only during hill climbs and acceleration, so their batteries usually last much longer. On a paved-road commute, your legs can likely put in 100 to 200 watts of power on their own, so using a low-key kit like this is like having an on-demand tandem partner.

ebike, battery, make, sure, best

For such “assist” rides, 250 Wh is a better starting point these days, according to Toll. If you’re going to be riding your throttle most of the ride, 500 Wh (that is, a 48 V, 10 Ah setup) is your starting point.

If you want something close to an electric moped experience—almost entirely throttle, 25 to 28 miles per hour—you’re looking at a 750 Wh setup. At that point, you should be checking your local laws and also considering whether you ought to simply buy a dedicated ebike, because in terms of price, design, and safety, you’re likely better off with one.

My wife’s ebike is working well. Because she can safely store her bike at work and at home, she removes her battery only about once a week for charging. She gets most of the exercise of biking but can push a button to get a faster start at intersections or to tackle hills. It has made her more confident in biking around the city, which means the local bike shops still get some business in accessories, lights, and more.

Do you need to upgrade your brakes?

If you’re installing a lightweight battery and motor that you expect to use mostly as an assist to active pedaling, your current brakes may be fine. Disc brakes provide better stopping power, especially in wet conditions, but a good rim brake can suffice for commuting-focused rides. Toll said he spent three years riding a DIY 1,000-watt ebike with mechanical V-brakes (the kind you might see on a 10-year-old mountain bike), and it worked out well. “It’s more about the quality of the brake,” he said. At a minimum, though, check your brake pads and performance, or have a shop do a tune-up, when you’re installing a kit.

Many ebike kits and motors come with replacement brake levers, or sensors that can attach to your existing levers. These shut off the motor when pressed so that your motor stops pushing immediately when you mean to stop. I haven’t found them helpful on my own 250-watt setup (more on that in a bit), but there’s no harm in installing them.

Where should you buy a conversion kit?

There’s no one ebike kit that I—or anyone—can recommend for most riders and bikes. But Adam Ostlund, Micah Toll, and Karl Gesslein, ebike enthusiast and author at ElectricBike.com, all offered one bit of buying advice: Never try to “save money” by hunting for cheaper batteries. A cheap battery is almost always disappointing—and sometimes dangerous.

Bike batteries usually consist of a series of 18650 cells that are connected to one another and a battery-management system and then packaged into various shapes. Reputable battery makers and ebike-kit sellers use the best-quality cells from brand names like LG, Panasonic, and Samsung. In contrast, most discount sellers use lesser cells, from lesser-known makers, that have diminished capacity, voltage, and longevity, and their controllers can be equally suspect. Buy from a dealer with an established presence and return policy.

You can often find motors, batteries, controllers, wires, throttles, sensors, and other accessories sold separately, but unless you have a few conversions under your belt, you’re better off with an all-in-one kit. Kit makers have spent a lot of time testing how components work together, and they should be available for troubleshooting. Ostlund noted in our interview that Electrify Bike custom-programs some of its kit controllers so riders aren’t stuck with the often aggressive acceleration curves of some motors that are meant more for delivery workers than for weekend warriors.

Ebike-kit companies that were mentioned by the experts I talked to, are linked in ebike-enthusiast subreddits, and have generally built a good reputation include:

  • Luna Cycle (affiliated with ElectricBike.com and Gesslein)
  • Electrify Bike Co. (Ostlund’s shop)
  • Grin Technologies (batteries, motors, and kits)
  • eBikeling, Leeds, Hilltopper, Dillenger (hub kits)

What about Swytch kits?

Search online for ebike kits (or in the Комментарии и мнения владельцев posted on this article after its original publication), and you’ll see Swytch mentioned a lot. It’s a UK-based company, but it has a US warehouse for returns and distribution, as well as a one-year warranty on most parts. The company offers 250-watt, front-hub-based full conversion kits for bikes with 26-inch and 700c wheels, as well as for Brompton folding bikes. You have to preorder your customized kit, and you might wait a while, as Swytch prepares and ships kits in batches.

Swytch’s main hook is its unique battery and connector, which clicks on and pops off your front handlebars at the press of a button. Most people have room on their bikes there, and the design simplifies removing the battery when you’re locking up. Swytch recently announced the smartphone-ish–sized Air battery for those who value even more portability, and lighter weight, over range.

Swytch sent me a test kit for my own bike—a 2018 Norco belt-drive hybrid with 700c wheels—with a Pro battery (30-mile range) and both a cadence sensor and a throttle. After jumping on a video call to double-check my fork dropout width measurement (an important detail for any conversion kit), I ran the cables and installed the kit without much hassle.

My bike is already on the heavy side, and I’m biking for errands or recreation more than personal records, so the roughly 3 pounds of difference that Swytch’s motorized front wheel adds is tolerable. You’re more likely to notice the 4-pound battery on the handlebars, but that feeling soon disappeared for me—and so did hills, and starting on an incline, and feeling weighed down by cargo.

There are better ebikes for those committed to riding electric every time or for those interested in commuting longer (or steeper) distances with less pedaling, but I’ve enjoyed the versatility of the Swytch kit for weekend trips and weekday errands. If hauling a battery around will be a pain, or the ride is real short and my knees feel great, I can skip it. If I want a faster, smoother ride, I can grab the battery and head out. If bike space and versatility are a priority for you, the Swytch kit is worth considering.

If you’re unsure about any aspect of your conversion, look for your bike model on the Endless Sphere forum or the r/ebikes subreddit, or simply search the web for your bike name plus “ebike.” Bike owners who have stealthily converted their bikes into electric-powered dynamos love to tell people about it. Not that I’d know anything about that.

This article was edited by Christine Ryan.

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