Can You Fix Your Electric Bike Battery. Bosch ebike battery rebuild

Can You Fix Your Electric Bike Battery?

Electric bike batteries are one of the most critical components of an eBike.The motor and many other features are limited once the battery no longer functions as it should. The first instinct that many eBike cyclists have when something goes wrong is to try and fix the battery since restoring one you have seems like it would be less expensive than buying a new one.

While it is possible to repair an eBike battery, especially if you only have a minor performance issue, the reality is that most eBike batteries aren’t worth the effort of trying to fix them. This is especially true when you have a severely damaged battery. Trying to fix it can cause you to get hurt.

However, because eBike batteries range in issue, we wanted to split our guide into two sides. First, we want to explain some easy tricks that will resolve the most common problems people have with their eBike battery. If none of these suggestions work, you’ll be at the point where replacing your battery is better than trying to repair it.

We hope our guide resolves your electric bike battery issue or at least explains why you’re better off getting a new battery rather than trying to make your old battery work.

Tip #1: Do a 24 Hour Full Charge Cycle

Like other batteries, electric batteries can sometimes enter a faulty, negative, or non-existent charge state where the battery doesn’t retain the full charge that your display says it has. This is one of the most common problems with eBike batteries. It can happen when you don’t use your battery for an extended period, when you ship your battery, or when you only charge your battery for a couple of minutes, or just randomly.

Fortunately, this is one of the most straightforward issues to fix with an eBike battery. All you have to do is leave your battery plugged in for about 24 hours. The constant feed of electrical energy over a day clears out any false or negative energy built up in the battery.

This also helps the BMS (battery management system) clear out any glitches it might be having. When your battery isn’t performing as well as you expect, letting it charge for a full 24 hour period is one of the best things you can do.

Tip #2: Clean Your Battery, Charging, and Frame Ports

If you have a removable battery, you’ll often be taking it off your frame so you can charge your battery indoors. While this is a great feature, it often results in crucial battery and frame ports being left exposed. Exposed battery ports then begin accumulating dirt, mud, and other debris that prevents your battery from being mounted correctly. This is why you might think your battery isn’t working properly when a failure to connect is the real issue at hand.

If you don’t think that your battery is being appropriately mounted, clean out the frame port and battery connection points to try and resolve the issue. Because you will be working with electrical components, make sure you use a safe or rated cloth for use with electrical equipment.

Typically, we use a dry microfiber cloth to clean out the charging and battery port when it’s getting dirty. While we usually avoid spraying anything on our cleaning cloth, but a small dab or squirt of a general cleaning solution can make cleaning a little easier. Be sure to follow the same tips if you don’t think your charger is connecting correctly!

Tip #3: Use a Multimeter Tool to Check Your Battery Voltage

If you’ve tried the above steps and you still don’t know what’s wrong with your battery, there is a way to check whether it’s worth attempting to fix or not. Using a multimeter measurement tool, connect your battery to the device to get a voltage reading for your eBike battery.

If you are within 80% to 85% of your eBike battery recommended voltage, then it is in good enough working condition that the issue is likely something other than the battery itself.

If your voltage is below 80%, you may have a blown cell, at which point your battery isn’t worth trying to salvage. While it might only be a couple of cells that are blown, installing new battery cells to pair with the old ones will lead to serious performance discrepancies that range from uneven charging to massive battery failure. Please consult the eBike manufacturer for warranty coverage if your battery is below 80% voltage despite having been given a full 24-hour charge.

Reason #1: It is Very Hard and Requires Multiple Tools to Do it Right.

Electric bike batteries are not only one of the most critical components on the eBike frame but also one of the most complicated. Depending on who you ask, the eBike battery may be even more complicated than trying to service and repair your eBike motor. Just to open a battery up without damaging the shell of the eBike battery can be an arduous process, requiring several tools to do it properly.

You have to be a skilled, experienced technician to successfully open, repair, and close an eBike battery without damaging it. This is a time-consuming process even for experienced eBike repair technicians, with the total parts and tools needed adding up to several hundred dollars. If you do it wrong, you can likely start a fire or cause some other issue that permanently damages the battery or even cause bodily harm.

Reason #2: It is a Very Expensive Process.

Due to the complicated nature of eBike batteries, many people send them to repair technicians to get them looked at instead of fixing the battery themselves. Depending on the issue, the repair cost may run a quarter to half the price of buying a brand new battery.

Even if you do it yourself, you’re still likely going to spend a lot of money just to get your battery working again. Cells, wiring, a soldering kit, and several other specialized tools required to fix significant eBike battery issues all add up. Cost alone is a significant consideration, but as we’re about to explain, you’re not getting much value for your investment as well.

Reason #3: You’re Likely Going to Have Persistent Battery Issues

Battery cells degrade over time, with BMS systems in your battery helping regulate and even out the performance differences as batteries break down. The problem is, BMS systems can deal with minor discrepancies between the dozens of individual cells within your battery. Once you pair a brand new battery cell with an old one, your BMS system has a much harder time trying to even out performance.

As a result, there are several different persistent battery issues common in eBike batteries with uneven cells. Disrupted and slower charging is typical as your BMS tries to feed different energy outputs to other cells. Sputtering or erratic motor problems is another, especially when you’re trying to use a motor with a higher energy drain. Worst of all, the new cells can cause the older cells to overload and explode, which will damage the battery and potentially start a fire. If you are replacing a few of the cells on a battery, you are better off replacing them all, at which point it just makes more sense to buy a brand new battery.

Conclusion: If Your Battery Breaks, Consider Upgrading Instead of Fixing

Being thrifty and doing your best to make the most of old equipment is an important virtue to have in life. It is imperative with eBike batteries since there isn’t a sound system in place yet to recycle and reuse old and broken down batteries.

However, while recycling and environmental awareness are important, staying safe and not causing fires is just as important. Due to the performance, cost, and potential harm caused by improperly repairing an eBike battery, it is highly recommended to upgrade over fixing serious issues.

As we noted above, there are minor issues you can resolve without resorting to opening up the battery. From our experience, these fixes troubleshoot the majority of battery issues reported to us by our readers. For serious battery performance issues that can’t be easily fixed, though, do yourself a favor and upgrade to a new battery to keep yourself, your bike, and other people around you safe while you ride.

Thank you for reading our blog post discussing eBike battery safety and repair. Please leave a comment below if you have any questions or if you want to know our favorite battery upgrades!

EBike Battery Rebuild

This Instructable is not meant to teach you How To but rather Why Not To rebuild your own eBike battery. Having just completed a months-long rebuild of mine, I have a list of painful lessons to share, all of which add up to this one piece of advice: if you can purchase a new lithium battery pack for your eBike, do so. There’s a lot going on inside your eBike pack, welding batteries is a finicky business that requires specialized equipment that’s not good for much else, the final product is unlikely to be really reliable or to last a very long time, the chance of fire or explosion is real, and there are probably other projects from which you can learn a good deal more.

Step 1: So What Does Rebuilding an EBike Battery Entail?

Really, you’re still reading? OK, let’s get into it.

The big, heavy brick that powers your eBike is a set of battery packs wired serially with a controller that governs how each set is charged and monitors the battery’s performance when charging and being discharged. Each battery pack is itself made up of individual cells (which is what most people think of as a battery, AA, AAA, what have you). To rebuild such a pack the main steps are as follows:

  • Open the battery casing (may be surprisingly difficult: they are usually sealed against water, so you will probably destroy the waterproofing and the warranty alike upon doing so).
  • Disconnect the various leads, some soldered, some glued, that monitor electrical flow and temperature, making sure to keep good track of what goes where. Eliminate silicone plugs or other material used to hold the battery packs or individual cells in place. Strip out any tape or other additional material you find inside, again, taking note of every piece, its location, and what’s under it. Details count here!
  • Remove the individual packs, making very careful sketches of the sheet metal formations used to define each of these packs, top and bottom. Details count here too!
  • Strip the connecting metal from some of the individual cells in each pack; you will need these dead cells to practice on as you prepare to assemble a new battery pack (indeed, you may need all of the dead cells for this purpose) and will probably want to practice spot welding on some of the stripped metal.
  • Source your new materials: new cells plus extras, and at least twice as much sheet metal as you think you will need to recreate the sheet metal formations mentioned above. (Note that you may wish to use a different thickness of sheet metal than that used in the original pack but probably don’t want to use a different type of metal; typically, you are buying a highly conductive nickel alloy.)
  • Beg, borrow, or buy a spot welder. Do not beg, borrow, or buy the one shown above or any other that is intended for hobbyists: you will probably need to make several hundred individual welds in order to build your pack, and will require a professional grade piece of equipment to do so. (So at least there’s that: by the end of this you will no longer be a hobbyist spot welder.)
  • Practice a lot with your new spot welder, your old metal, your new metal, and your old, dead batteries; figure out how to deal with edge cases, such as welds at the end of a strip.
  • Recreate the sheet metal formations using your new metal and a pair of shears or, more ideal, a laser cutter.
  • Weld the new batteries to the new sheet metal formations at the right points and with the correct orientation in order to create your new battery packs.
  • Place the new packs in their correct positions. Attach each wire and lead in the correct spot as indicated in your careful notes, using specialist glue or soldering as appropriate.
  • Kit, glue, tape, and otherwise physically secure the battery according to your careful notes.
  • Return completed battery to its original housing and test the new battery by charging it as per usual.
  • Assuming the battery charges correctly, start using your bike and charging normally.
  • Assuming nothing goes wrong, reseal the battery in its housing before the first rains.
  • Don’t forget to dispose of the old cells responsibly.
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Be sure to take lots of pictures and movies for the sake of reference and to record suitable measurements of voltage throughout as well.

Step 2: What Makes This So Difficult?

You face two major challenges should you undertake this project. First, the new battery has to replicate the old one in essentially every detail. The controller expects a particular voltage under particular conditions, and is more or less sensitive to temperature, too. As important, you’re dealing with a lot of electrical connections in a small space, and a lot of electrical power, so shorts are out of the question. and yet surprisingly, one might say shockingly, likely to happen. Precision counts.

But it’s the second one that is really tough. Heat is bad for batteries, but heat, generated by electrical current, is what you’re using to weld the cells to the metal strips that will conduct electricity between them. It is important to get as strong a weld as possible but you must inject as little heat as possible into the battery. Too much heat and you degrade or even puncture the battery, too little and you end up with a weak weld and, eventually, a loose connection deep inside your construct, with unpredictable but by no means helpful results. It’s a fine line you’ll be walking. What’s worse, there are many factors that influence the quality of a weld: the cleanliness of the surfaces being welded; the thickness and shape of the electrodes; their placement in relation to one another; the firmness of the contact between them and the metal being welded, and between the metal and the battery beneath; the length of time allowed for the weld; the mass of the metal adjacent to the points being welded; and likely other factors, too. Again, precision counts. but how are you going to achieve precision with these many variables across a couple of hundred welds?

Step 3: Seriously, You’re Still Thinking About Trying This?

Consider just a few tricky bits in one of the packs, pictured, under construction, above. Bent metal, lots of extra insulating tape, a punctured battery. None of this is the product of carelessness, it’s the inevitable (as best I can tell) result of working with hobbyist equipment (a manual, lightweight welder, as opposed to a computer-controlled, industrial one; scissors instead of a heavy-duty laser cutter). But maybe you like a challenge, hopeless odds, playing the underdog. Very well, if you must, here are a few recommendations, since you insist on proceeding:

  • Get a computer controlled welding device: Yes, there are a lot of variables that impact the quality of a weld, but with a computer in the loopthe Mighty Zimbra hacked one together using an Arduino, of courseyou can at least control the amount of time the circuit is left open.
  • Get a heavy duty welding device: Spot welding works by running lots of current through the welder to the metal, but if the welder itself is not beefy enough that current, over the course of the many, many welds you will need to make, will start to melt the machine from the inside out. We had to battle with switches welding themselves open, constant hassles with fuses, and welding wands that became literally too hot to handle. Spare yourself these problems.
  • Work in a ventilated space: You are melting metal. It stinks. It is certainly not good to inhale. And you are doing a lot of it.
  • Save your old batteries to practice technique: This should be obvious.
  • Source more batteries than required for your pack: Even though you took my advice and practiced lots and lots and lots on your old batteries you are still very likely to destroy some new batteries along the way. The batteries are cheap, have some spares to hand.

Good luck to you, brave Maker, and may your project fare better than mine!

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The best electric bike conversion kits 2023 and how to fit them

The best electric bike conversion kits can give you an extra boost of power without the expense of purchasing a new electric bike. We’ve fitted some of the best e-bike conversion kits ourselves, so will walk you through the process, how easy it is and how the different systems perform.

E-bikes are soaring in popularity – and for good reason. The best electric bikes replace a car for running errands around town and greatly increase the distances it’s possible to ride on one of the best commuter bikes. An e-bike can also be a great tool for boosting your fitness, whether that’s enabling you to ride with a greater range of people or offering the motivation of a greater range of roads to explore.

But is an e-bike worth it,? As the best ebike conversion kits promise to add power to an ‘analogue’ bike for a lot less than a full ebike, it’s an easy, cheaper way to get an electric boost.

In this guide we’ll take you through the surprisingly broad range of benefits an e-bike conversion kit has to offer and – most importantly – how to perform an e-bike conversion, based on our hands-on experience. For a walk-through on how to do it, you can check out the video above or read on for a step-by-step guide – it genuinely is so much simpler than you would think.

When buying an ebike conversion kit there are a number of factors you’ll need to consider. Most importantly you’ll need a kit that will fit your bike. To help with this it pays to take a few frame measurements, notably the width of your forks and the width of the rear stays, as well as noting the wheel size and the type of brakes. You can then match these details to the kit specifications.

Naturally you’ll also need to consider the cost and how much you chose to spend on an ebike conversion kit will be dictated by not only your budget but also your needs. If you’re unsure of just how much you’ll use the converted bike then it’s prudent to opt for a cheaper kit. you can always upgrade down the road.

You’ll also want to consider where the motor will be located, and match this to your bike and your mechanical prowess. Front hub motors are typically the easiest to fit, while mid-drive motors require more effort. A rear hub motor lies somewhere in between the two, and like a front hub option is applicable to a wide range of bikes.

Other considerations include the type of battery and the wattage rating. 36 or 48 volt battery is standard, with wattage usually running from 300 to 600 watts.

The Swytch kit is super-simple: just swap out your front wheel, wire up the controller and battery and you’re off. The battery is also very compact, allowing you to remove it from the bike easily to carry with you.

The TongSheng kit positions the motor at the centre of the bike, so it will fit to a wide range of designs. It’s lightweight for its high torque and power output, although you’ll need to buy the battery separately.

The Voilamart kit is an inexpensive rear wheel conversion option, although you’ll have to source a battery separately. It’s slightly fiddly to fit as well and requires additional waterproofing if you plan to ride in wet weather.

The best electric bike conversion kits

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Our team of experts put in hard miles testing cycling tech and will always share honest, unbiased advice to help you choose. Find out more about how we test.


Wheel sizes: Each wheel is custom built – specify your required size at checkout (Bromptons also catered for)

Reasons to avoid

The newly updated Swytch system is one of the simplest conversion kits to fit out there. The latest version, launched in August 2022, has a smaller, neater battery pack that improves the bike’s dynamics and lowers its weight. There’s the choice of the Air battery (700g, range 15km) or the Max battery (1,100g, range 30km). Both use the same mount, which places the battery to the front of the handlebar.

The motor sits in the front hub and we found it to be pretty discreet. Incidentally, the new batteries will work with the original motor and pedal sensor, so if you already own the original kit you can upgrade it with just a new battery without having to buy the whole kit again.

The Swytch kit is incredibly easy to fit. It took us around 30 minutes working at a steady pace.

We tested it on both a reasonably light two-speed steel bike and a heavier Pinnacle utility bike. It transformed the ride of the two-speed bike, making it fast, nimble and responsive. We also found the stated range to be conservative: after 20 miles on setting number two (medium assist) it had only used two bars out of five on the battery.

With the heavier Pinnacle on maximum assist (and on draggy routes) we were getting slightly under the 30km for the Max battery. As with all e-bike batteries, range depends on the terrain, weight of bike and level of assist.

Great customer support makes this one of the best kits for people who are new to working on their bike and who aren’t familiar with electrics. And even if you do have a strong background in both those areas, a simple system is always appreciated.

Reasons to avoid

Like the Bafang mid-drive system below, the TongSheng offers the same benefits of compatibility with a wide range of bike designs and a high torque for steep hills and off-road terrain. However, the TongSheng mid-drive does manage to be a little lighter than the Bafang for approximately the same power.

This model doesn’t come with a battery included, so you’ll have to source your own 36v item. As a rule of thumb, around 10Ah will give a range of 29km / 18mi, whereas going up to 18Ah will typically give around 53km / 33mi, so be sure to factor that in when you’re making your choice.

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There’s a huge range of batteries sold on Amazon, but Green Cell is a particular brand we’d recommend.

We found fitting to be reasonably easy. As with most mid-drive systems, you replace your crank and chainring with the one provided in the kit. There’s an LCD display for attaching to your handlebars and you’ll need a battery to be hooked up to the motor.

Read more: TongSheng TSDZ2 conversion kit review

Reasons to avoid

A mid-motor drive system offers a number of benefits over hub-driven conversion kits. With the power delivered at the cranks it can produce more torque, making it more effective on particularly steep and bumpy terrain.

Another perk is that the compatibility is much greater – no concern about wheel diameters, hub widths, axle standards and brake type. No matter whether you’re running rim brakes or disc, quick release or thru-axle, the crank driven system is compatible with all.

The only proviso is that the frame material must be alloy and the bottom bracket width is 68–73mm – but that covers most bikes you’re likely to be fitting this system to.

There are a few aspects to be aware of, the first being that this system doesn’t include a battery and that typically makes up about half the cost of a conversion kit. Finding an e-bike battery is quite straightforward with many being sold on Amazon, with Green Cell being among those we’d recommend.

Just make sure to get a 36V one for this motor as a higher voltage can damage it. Also you should be aware that capacity of 10Ah will give you a range of about 29km / 18mi, while a capacity of 18Ah typically gives about 53km / 33mi – so be sure to factor in the distances you’re planning on riding.

Reasons to avoid

This radically different approach from Rubbee makes for an e-bike conversion with much fewer parts. The battery and motor are housed in a single unit which powers the bike directly turning the rear wheel with its integrated roller.

Not only is the initial installation notably fast and easy, the quick release system means that you can take off the unit for rides that you don’t wish to be assisted on. At 2.8kg, it doesn’t add much weight to that of the bike, making the bike easier to handle.

The range of this model is quite low, limited to Eco mode it only offers a range of 16km / 10mi – although taking the device off to charge at the other end is easy to do and it only takes an hour to top up. There is the option to increase your range by buying additional battery modules that fit into the base unit.

Up to three can be accommodated, which in turn increases the maximum range to 48km / 30mi, or around 23km / 14mi with moderately heavy use. However, unlike many other e-bike systems, the Rubbee X supports regenerative braking, allowing you to scrub back some power on the descents.

Reasons to avoid

Bafang is a well established maker of electric bike motors and offers a front hub based motor, if you’re not a fan of the bulky profile a mid motor conversion system creates. You can buy this kit without a battery – although why would you? – but if you sensibly also opt for a power-pack there’s a choice of amp hours, and you can select either a downtube or a rear-rack mounted version.

The setup follows the same principles as most front-wheel e-bike conversions. First you need to set up the wheel with a disc rotor, tyre and inner tube and install that into the bike. Then attach the cadence sensor – so it can tell when you’re pedalling and need assistance – then attach the battery and the LCD display and you’re essentially good to go!

It’s worth bearing in mind that although this conversion kit comes in many different wheel sizes, it is only compatible with bikes that have a front disc brake and a Quick-Release axle. If your disc brake bike is a newer, more expensive model, it might not be compatible, so worth checking first.

Remember, that in the UK electric bike laws mean that e-bikes are not permitted to have a power output of more than 250w and shouldn’t propel the bike when it’s travelling more than 15.5mph – you’ll have to make sure you select the right model with the relevant limitations.

Reasons to avoid

We’ve also tested the Voilamart kit, which comes with six main parts: the replacement rear wheel, the replacement brake levers, the control screen, pedal sensor, throttle and the control box. It doesn’t come with a battery however.

On review we found the kit pretty straightforward to fit, although you’ll need to remove the bike’s crank to fit the pedal sensor and this element of the conversion was a bit fiddly. Another potential drawback is that the connectors, which link to control unit, aren’t waterproof, with only a bag supplied to house the delicate electronics. While it does a good job of keeping everything tidy, we decided to buy a plastic enclosure, cut the wires to length, solder the connections and then heat shrink for added protection.

As for the ride, the rear wheel kit delivers plenty of power. However, since the pedal sensor only detects when you’re pedalling rather than how hard you’re pedalling it delivers the power as soon as your start to turn the crank arms. Fortunately, you can quickly adjust the level assistance, with five power options available.

All in all the Voliamart rear wheel kit is an affordable way to ‘go electric’, although it requires you to be mechanical competent to fit it and you’ll need to factor in the additional cost of a battery.

How to convert your bike to an e-bike in four steps

Here’s our step-by-step guide to how to add an electric bike conversion kit to your pedal-powered bike.

Swap the tyre and tube

Firstly, remove the tyre and tube from your current front wheel and then install them on the new wheel from the kit. Make sure to check if the tyre is directional, if it is, ensure that the tyre is mounted so that the cable sticking out of the hub is on the left-hand side (non-driveside) when the wheel is installed in the bike – otherwise it’ll be powered in the opposite direction to your direction of travel!

To swap the tyre and tube over, you will need some tyre levers and a pump. If you want to go over how to do these, we have a guide that can be accessed here.

Final points are to do up the nuts on the wheel’s axle to keep it firmly in place in the forks and to check that the brakes are correctly adjusted for the new wheel. If you’re unsure how to do that, we have another guide here.

Attach the bracket to the handlebars

There is a strap that needs to be attached to the bars to keep the bracket in place and stop it rotating around. There are also some adaptors included in the kit which can be used if your handlebars are a little skinnier.

But essentially all that’s needed to be done here is a couple of screws to clamp the bracket tightly to the bars.

Attach magnet disc and sensor

The magnet disc has a split design so it can just clip around the inside of the left (non-driveside crank) and is then held in place by its retention ring. Next, stick the sensor on the frame directly in line with the magnets – this will ensure that the sensor can tell when the cranks are moving.

Plug in the cables

The thickest one is the main power cable and that just needs to be plugged into the cable extending from the hub. The other orange cable attaches to the cadence sensor and this just needs plugging in as well.

It’s then a good idea to use some cable ties to tidy up the lengths of the cables a little bit, so they aren’t flapping about and risk getting caught on the spokes or on the cranks.

The blue cables, you don’t need to worry about, these are for an optional brake sensor upgrade kit.

Why convert your bike to an e-bike?

What types of conversion kit are available?

You can get conversion kits that power your front or rear wheel or power the bikes via the cranks.

Wheel-based systems usually have a hub motor and require replacement of your existing wheel with a compatible motorised one.

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The alternative is a system like the Rubbee that drives your wheel by pushing on the tyre. Tyre wear can be an issue here though.

Finally, there are systems that power the e-bike via the bottom bracket.

Usually the e-bike’s battery will bolt onto your frame or be attached to your handlebars, although sometimes you can fit a battery pack to a rear rack.

We’ve more on compatibility. which can be an issue. below.

How much does it cost to convert a bike to an e-bike?

vary depending on the type of conversion kit and the size of the battery. To give a rough Band, you can expect to pay a total of between £500 and £800 from a reputable brand, but there will be outliers at either end.

Is it worth converting a bike to an e-bike?

There are many reasons to upgrade your bike to offer a little e-assistance. On the one hand, it can greatly increase the usefulness of your bike, enabling you to replace short car journeys – such as around town, to the shops, or to work – with going by bike instead.

It’s a lot more environmentally friendly getting about on two wheels than in a two-ton metal box. It can also save you time – bikes are able to take more direct routes and are less affected by traffic, as well as eliminating the need to search for a parking space at the other end.

But beyond just their practical benefits, e-bikes can also be a potent tool for boosting your fitness. Consistency is key when it comes to exercise, so making commitments with friends is a great way to ensure you’re heading out the door. Previously, differing fitness levels could make it difficult to find a riding partner but with an e-bike levelling the playing field, getting in a productive workout (for both of you) with a friend is much easier to do.

Added to that, an e-bike can be much more motivating in that it opens up a far greater range of roads than you’d be able to access just under the power of your own two legs. Exploring new roads is part of the fun of riding a bike and an e-bike can help preserve that.

Can you convert any regular bike to an e-bike?

Most bikes can be converted to an e-bike – it just requires getting the matching the right conversion kit to match the specification.

For conversion kits where the motor is located at the wheel’s hub, you’ll need to consider the wheel’s diameter, the width and axle standard of the hub and whether it uses rim or disc brakes. For instance, a 700c (AKA, 28”) disc brake wheel with a 100mm wide quick-release hub is a relatively common spec. Once you’ve determined what type of wheel you need, the conversion is quite a straightforward process

Crank driven systems are generally easier in terms of determining compatibility; the requirements are typically just an alloy frame and a bottom bracket width of between 68 and 73mm – which is the standard for all road and mountain bikes, it’s only specialist bikes that have a different spacing there. In replacing the crankset, these systems are a bit more involved to fit than a hub system, but still well within the remit of a home mechanic.

Other kits, such as those that directly drive the rear tyre, have almost universal compatibility – provided your tyres aren’t too heavily treaded.

Are electric bike conversion kits any good?

You won’t be getting the very best motors and the largest, seamlessly integrated batteries with an e-bike conversion kit. But with that said, e-bike conversion kits are much cheaper than purchasing a whole new e-bike and they do deliver many of the same benefits.

Converted e-bikes are great for commuting and utility cycling, giving that extra boost to help flatten hills, motor along the flat and lug about heavy loads. E-bike conversions are also good for leisure cycling, helping to moderate your effort level as needed and greatly extending the range you can explore.

For more specialist utility needs, buying a new cargo e-bike would help boost your carrying capacity and range. Equally, for the aesthetically conscious, the latest breed of e-road bikes are almost indistinguishable from a non-powered bike at first glance. Then again, both those options are much more expensive than a conversion.

How we test

Where we’ve been able to link to a review, it means that we’ve put the ebike conversion kit through its paces. We’ve assessed how easy it is to fit and maintain as well other factors such as quality of the components and battery life and charge time. Riding the bike once fitted with the kit, we’ve taken into account the ride quality, the ease of use and the battery range.

Where we haven’t yet had the chance to review an item, we’re still confident in recommending it as one of the best, because we either know the brand really well, and have probably tested another product or the previous version and can still happily recommend it as one of the best.

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