Electric Bike Troubleshooting—Part #1

Not all E-bikes have safety motor cut-off switches on the hand brakes. A broken wire here, binding lever or bad switch can keep your motor from running.

Modern E-bikes are designed to be problem-free.   Of course they still need the standard bicycle maintenance you would expect.   Like every electro-mechanical device, there may come the time where the electric-assist system just doesn’t wok right.   This will be our subject in today’s article.

It should go without saying that the only way to know if it is having a problem, is to know how it normally works.   So as you ride your E-bike, pay attention to how the controls and indicator lights operate during regular use.   Your owner’s manual will go into this, and it is up to you to understand each of the controls and their functions.   This will be part of the key to troubleshooting any problems you may encounter.

If trouble arises, make a mental or written note of each thing that seems different or wrong.   Whether you attempt the repairs yourself or have a E-bike mechanic take care of it, the list of things you notice can be a road map to help solving the problem.

I do recommend having a qualified mechanic do the troubleshooting and repair.   That is one of the big advantages of buying your E-bike from a local dealer.   Not everyone is lucky enough to have an E-bike shop nearby, so you might have to dive into it yourself, or enlist the help of someone who is not 100% savvy on the repair.

The manufacture will do everything they can to help you over the phone or email, and they too will need an idea of the maladies.   So make that list.   If the bike is still under warrantee, they will ship out the needed parts free.   They might suggest you send them the whole bike for the fix.   In some ways this can be the best solution, but don’t expect them to pay for packing and shipping.

The electric-assist system consists of several parts.   The motor, battery, charger, control unit, wiring harness, and all the input devices need to work as a team for correct operation.   Each and every item needs to be correctly plugged in and functioning right. Your problem could be as simple as a loose wiring connection, or at its worst, a failed component.   Our first goal before the repair, is to decide what to repair.

Before you start this process, remember that safety is the most important tool in your workshop.   Keep your common sense in top gear and think before you leap.   On the subject of thinking, it is so important to stay sharp during all your tests and repairs.   Thinking can solve many problems that tools can’t.   Don’t hurt yourself or make the problems worse.   Please be careful and if you aren’t up to the task at hand, by all means, seek a professional.   That said, let’s dive in.

Look for the obvious things first.   Broken or loose wires can be visible, although sometimes they can be in a hidden spot.   A battery that is not fully inserted or plugged in is a quick fix.   A throttle unit that feels mechanically broken when you turn it should make you think that is the problem.   A smell or excess heat from the control unit or motor is a tell-tale sign to suspect that component.

Next up is to evaluate your problem.   Things like less battery range than normal can be a sign of a battery in need of replacement.   More noise than normal will usually lead you to the motor.   Certain things like braking, shifting and noise maladies are more than likely regular bike problems that have nothing to do with the electrical system.   Chances are if you are reading this, your motor will not activate to give your bike an assist.   That is the direction this post is now taking.

A battery that is not fully inserted, or plugged in can be an easy fix. You can see the fuse holder at the top of this lithium battery.

Ok, your motor will not run when it should, what should you do?   You have already looked and felt for the obvious visible things and that hasn’t led you in the right direction.   Let’s look at the source of power for your bike, the battery.   Are your display or battery charge indicator lights coming on when you switch the power on?   This will be our first needed clue.   That could indicate a bad battery, connection or failed ECU (electronic control unit).   You did recharge your battery, right?   This sometimes overlooked chore could be the simplest of reasons you’re having problems.

Has it been charging like it always does?   Are the charger lights working like you’re used to?   Many E-bike batteries have a fuse built-in to them that is accessible from the outside.   The fuse can fail, just because, but normally if it does, there is a problem with the battery or wiring.   The fuse is there to protect your battery and bike from an overload of power that can cause intense heat or fire.

A simple voltmeter test can give you a general idea if the battery is holding juice and if the fuse is bad.   Most batteries should read about 2-3 volts more than their ratting on the voltmeter.   24, 36, and 48 volt systems are the most common.   You will need to know which you have before you proceed.

Some batteries have two wires or connectors where the reading can be taken.   Some have more, and that can be the beginning of your confusion.   Those extra connections are to feed info about the battery cell condition and balance to the computer, or battery temperature information.   They won’t give you the readings you need.   If voltmeter tests already sound like more than you understand, you are going to need some help and this post won’t be enough to guide you.   So take your list of noted problems and search for a E-bike expert.   If you’re good, let’s keep going.

If you found a bad fuse, replace it with the same exact item and try again.   If it blows out again, I would suspect a shorted battery or bad wiring inside the case.   I have had broken wires inside the battery case at the fuse holder on my E-Zip.   I replaced it with a automatically resetting circuit breaker and have had no more problems.   If the voltmeter won’t show the correct voltage, the battery is probably bad and in need of replacement.   The problem could be with the charger instead.   Best to replace them both as a team.

With lithium batteries, you don’t want to open the casing.   If you have SLA (sealed lead acid) batteries, be aware of any fluid leakage they might have.   Any sign of a leak is cause for immediate replacement.   That fluid is caustic and needs to be cleaned correctly to prevent damage to your bike and battery holder case.   That is one of the many reasons lithium batteries are the preferred unit for E-bikes.

Well, I’ve run out of space for today, so this will be a two part article.   Stay tuned for the rest of the E-bike troubleshooting story.   Thanks for checking in, Turbo Bob.

“When all else fails, read the instructions.”—Often said but rarely followed.   I DO think it is a good idea.

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About Turbo Bob's Bicycle Blog

E-bike Enthusiast Vintage Bike Enthusiast
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115 Responses to Electric Bike Troubleshooting—Part #1

  1. Albert Hill says:

    you are troubleshooting information was extremely helpful I didn’t even know where the fuse was. Keep up your public information we really do appreciate it.

  2. Kevin says:

    Hi there, I have a Daymak Ecostar 48v 12ah E-bike and I’m having an issue that I can’t quite figure out. I bought the bike used and have looked up the user manual online. I can’t find anything helpful anywhere and I would like to avoid having to take it into a shop as I dont have one anywhere close. My batteries are in good condition, hold a full charge, not swollen, no leakage or anything like that. But the bike only runs at 15km/hr unassisted. When pedal assisted it runs to its normal speed so it has me completely baffled. Any input would be great. I’m not very mechanically inclined so respond as if I was an idiot. lol.

    • Hey Kevin. What I’m reading here is you don’t feel the bike is going fast enough with just the throttle—but correct speed when using the pedal-assist mode.
      Let me know if that is the case. The simple explanation would be that the throttle is not working right or isn’t being able to be rotated to the normal limits it should. If that is the case a new throttle might resolve your issue, they don’t cost much.

      • Steve Grycko says:

        Looking for USA source for all E bike parts.
        Need 5 mag. Hal sensor disk that goes over crank.
        Customer damaged inner area that goes over crank. Some of those small plastic holder clips are broken off.
        Help.

  3. Steve, my local E-bike guru is at San Diego Electric Bike in Solana Beach. I sure don’t get involved in any sales, I am an independent bike tester and reviewer. Get on the web, or call Pat at SDEB.
    Good luck finding the piece you need.

    • Steve Grycko says:

      No problem:
      Just thought you might have heard of a E Bike Parts Dealer.
      I found what I needed.
      It’s that 2-3 week “From China” lead time for delivery that sucks.

  4. Chris says:

    Hi .

    My son recently converted his road bike, having professionally fitted a rear-wheel drive mechanism powered by a (China sourced) battery. The details he has given me are as follows, if these make any sense. The battery is 48v/100 watt and may be called a ’20 AH’. All went swimmingly, until today when the LCD screen – which displays charge, power input, battery charge & kmph, flickered into life before going blank again, after which there was no power. Switching the system on and off just repeats this – the screen lights momentarily then dies again.

    My immediate thought was the the battery was flat or nearly flat, but my son assures me that it is fully charged – any other suggestions gratefully received.

    • Chris, even though charged, some voltage tests on the battery might be in order.
      From there I think I would suspect the ECU.
      Even an easier fix could be a poor connection or loosened connector.
      Let us know the progress and eventual fix.
      Thanks for checking out my bike blog, Turbo.

  5. Linda Corley says:

    Recently had a motor replaced on my Cyclamatic E bike. The mechanic replaced my 24 v with a 36v. My concern is that the 24 v battery will not be safe to use with the new 36 v motor. Is there a chance for fire?

    • Linda, sounds like your basic worry is not a concern. Motor are rated in different ways. As long as the bike is performing ok you should be fine.

      • Linda says:

        The mechanic informed me today that the new 36 volt motor that he installed does not work with the 24 volt battery. He jumped started it with a 36 volt battery and ithe motor started right up. The 24 volt battery shows that it is charged but it will not run the new motor. What could be the problem?

  6. Linda, if this is a brushed DC motor it should run on 24 volts, but slower with less power.
    I am getting the impression your mechanic is not as experienced as he should be, as he is the one that should be supplying the answers and solving the problem.
    The motor should be replaced with the exacting model. I am wondering if that was the problem in the first place.
    I am not familiar with that particular E-bike so I Googled it. That still didn’t give me much to go on as to what kind of electric system and motor it has—and there are several models.
    How old is your bike? And, how was the motor chosen as the defective piece?

    • Linda says:

      You are so right about the mechanic not experienced as he should be although he claims he is. This experience has been a nightmare. He has had the bike for 3 months. Only when I threatened to go and pick it up did he find a replacement motor for the one that had stopped working due to sand in the hub. He replaced it with a 36 volt motor not knowing that it needed a 24 volt motor. He should have checked this out. I thought that would be ok but it seems it is not. Can’t get parts from Cyclamatic so had to go after market. The new 36 volt motor works fine with a 36 volt battery but he does not have any for sale. The bike is 2 years old and rode seldom. Both the 24v and 36v motors are brushless. Now he is going to have to find a 36 volt battery to install in order for it to run. I paid $800 for the bike and now I’m going have to pay about the same amount to have it repaired. I”m thinking of going to his shop which is an hour away and picking up the bike and bringing it home. I’ll find someone else to work on it. Thanks for your help. – Linda

  7. Too bad. Normally moving from 24 volts to 36 volts is a good idea. Also the controller (and maybe a few other items) would need to be changed to complete the job.
    Might not be a bad idea to find someone more familiar with your bike to get it running right and dependably.
    Money is important—but a solid job and a trouble-free bike is the main goal.
    Good luck, keep us in the loop as to how things come out.

  8. Daniel says:

    I have a DIY 48v 1000w front wheel drive E-bike powered by a 48v 30ah lithium ion battery. Recently I have encountered a problem that I can’t solve. I was riding as usual to work, then suddenly halfway thru on the road, I can’t feel anymore torque from the motor and throttle. It suddenly powered off then could not start up anymore. 90% of the time controller is the one always giving prob. So I took a new controller to test to with no avail. Tested the battery’s voltage which turns out at 50v, which is full and seems healthy. Made sure no loose connections, but still my lcd meter cant power up, I tested with a led meter which lighted up when pressed and went off when let go. I just cant figure out whats wrong here. Not to mention troubleshooting the motor, the lcd wont even power up. The controller is fine, phase wire and powerline is not burnt. I tried all ways I could think off but the thing just won’t start up!!! Anyone able to provide me with any solutions ?

    • Daniel, some of your symptoms could be related to motor sensors, but not all. 50 volts is kind of weak for a fully charged 48 volt battery, I would expect more like 53 or 54.
      On the whole, like you said, controllers are a big problem area, so it makes me wonder if your tests with a ‘good’ one are really that.
      Dive deeper into the connections too.
      Let us know what you find as you fix your bike, Turbo.

      • Daniel says:

        Thanks for your reply Turbo, in my knowledge, the controller with a LCD meter switch, but no key switch connector, the bike can’t start up, which happens to be my case. Usually if the battery is faulty, then the lcd meter will fail to power up, however mine lighted up but just could not start up. Tested the motor wires with e meter spinning e wheel manually, the motor is fine. The controller used to test was a brand new and tested one that I got from my supplier. I’m not left with much choice, no matter how I examine the connections, there isn’t any loose ones. I even went change a new switch but still to no avail. My apologies, the voltmeter is showing 53 volt exactly, just referred back to the pictures i took during troubleshooting. My guess is the problem is still either lying around the controller or the battery.
        Super irritating and tedious to troubleshoot parts by part. I have no other choice but to use my 15ah battery to test if it works. If it does that means my 30ah is screwed. If it does not, I’m down to the controller which I will have to wait for the new one with the key switch then I can pinpoint exactly. If even after all this test, I still can’t find the issue then I may just give it up.

  9. Never say die Daniel. I do think a load lest on your battery is needed. It could have voltage but no real juice. Make it happen and get back to the fun.

  10. chris says:

    Hi there,
    Nice blog. I have a question regarding my ebike. The battery meter is high and the battery is fully maxed out. I get not a single light on my bike and it wont start, however when I disconnrct the brake light from the back of the bike, the throttle spins the motor, however I still have no lights anywhere 😦 please help!

    • Interesting problem Chris. Judging by the fact you have a brake light—it sounds like you have an electric scooter. I mostly do E-bikes, but they are similar in many ways. I would start with a factory wiring diagram and do some voltage and continuity checks on that light.

      • Chris, on most E-bikes they use motor safety cut-off switches in each brake lever. Seeing that the brake light on your bike is somehow connected to your problem, I would investigate those switches, along with the wiring, brake light housing connections and the bulb itself.

  11. Benyi Denes says:

    Hi there
    One question. I bought a 1000 watt 48 volt front E-bike motor set couple days ago. Everything worked good at first. Now it just won’t start. I checked voltages, connections, battery, etc-etc. Clicking sound from the motor.
    I can use a little help or idea what’s wrong with it.
    Best regards

  12. My first thought is the motor planetary gears might have stripped or loosened up some how. Kind of early in its life for that it seems. Sometimes sensors in the motor (or wiring connections) can fail causing issues similar (but not the same in my experience).
    The easy way is to get a warrantee return shipping label from the shop you got it from and let them deal with it for you.
    Let us know how it all plays out.

    • Benyi Denes says:

      Thank you I’ll do that,but I try replace the throttle first because voltage is just not right Best regards

      On Mon, Aug 3, 2015 at 5:17 PM, Turbo Bob’s Bicycle Blog wrote:

      > Turbo Bob’s Bicycle Blog commented: “My first thought is the motor > planetary gears might have stripped or loosened up some how. Kind of early > in its life for that it seems. Sometimes sensors in the motor (or wiring > connections) can fail causing issues similar (but not the same in my > experie”

  13. Alan morrissey says:

    My batteries are still in the green on a load tester, but all of a sudden my batteries are draining super fast and thoroughly. What would cause such a fast and complete powerdrain as in 8-10 blocks? And she drops right off and you can’t even try to baby it home ????

    • So the batteries have been load tested for voltage and amperage capacity and passed? If the battery is good, the issue is the bike or its electronics. Heavy binding in the drivetrain is a good place to check, although you would notice the lack of performance.
      If you had a Cycle Analyst installed it could help diagnose the problem..

  14. Trish says:

    I’m glad I found you to ask this question. On the black sealed box on the handlebar, I see a white broken wire coming from it.
    The black box is the with lights showing battery power left and I click through some to select either throttle, pedal assist or off.
    How can I replace or mend the wire coming from this?

  15. You don’t mention if things are working or not—or what brand of E-bike you are riding. If at all possible contact the shop you got it from—or the company that makes it. There is a possibility that the box can be opened and the wire repaired—yet many boxes like that are glued shut and can’t really be fixed easily. I would have to see it in person to get a better feel for what you are dealing with.

    • Trish says:

      I am using a ‘roodog’ chic ladies e bike. I have emailed and facebook messaged the retailer but have had no response. It is 16 months old now so out of warranty.
      How can I send a picture of the said black box for You to look at?

      • Trish says:

        The motor worked until I sat on a park bench 3 miles from our campsite.
        I walked it for a while in which time turning the throttle made the motor work for a second but then nothing.
        I rode it back with difficulty having no motor.
        When I got back I then noticed the white wire broken outside the black Box and concluded that this was the reason for the throttle not being able to make contact with the motor.

      • Sure, if you are on Facebook that would be the easiest way to have a look at the photos of the box. My site there is named the same as this one—Turbo Bob’s Bicycle Blog.

  16. Judy Glathar says:

    What does it mean if my bike is fully charged and has been sitting for several months but when I give it the throttle it just kind of jerks forward, ith very little power to pull itself. Is it possible it is because there are there low tires on my trike?

  17. Brian Staines says:

    Hello,
    I have a new (out of warranty) coyote connect bike which makes a repetative banging noise from the motor, but no traction assistance. The motor appears to be mechanically sound (inspected internally) any ideas ?
    Thank you Brian.

  18. Sofia says:

    Hello!

    My friends and I are turning an old bike into an E-bike. We’ve done all the wiring correctly and have the proper fuse but when we turn the ignition key, the motor starts running even when we are not turning the throttle and the throttle is in the closed/off position. When we pull the throttle down the motor goes faster (as it should) but when we release the throttle, it snaps back into closed position but the motor keeps running. The only way to stop the motor is by turning the ignition off.

    There’s no external damage to the throttle wire that connects to the control box as far as we can see and the wire isn’t constricted so we are simply stumped as to what the problem is or how to fix it.

    • Did you use a complete matched conversion kit from a name-brand company—or bits and pieces to do the conversion? For some reason it sounds like possibly the throttle you are using isn’t compatible with the motor and controller.
      If you say the wires are all correct, it makes me think you used a complete kit. Then I would contact the supplier for what they think is your next step to resolving the issue.
      How does that sound?

  19. donnywmcclure says:

    Hi Bob
    I have a DIY 48 V system . I built up this bike last fall and have been working on getting “the bugs” out while I dial in the mountings. The build is on a yuba mundo cargo bike frame that I completed with parts from myself and friends. In college I ran a small new and used gear/bike shop and worked on basic tunes as well.
    I originally purchased the bmc rear hub V3 on ebay and it has always seemed fine. The battery is new from calibike and I did have some issues but fixed them myself on the on off switch poor solder joint. The controller was used but I fried both it and the throttle switch last year by improper connecting. I replaced that with a new controller wired for my new throttle and plug and play set up for my three larger/phaze wire hub ( yellow, green and blue) plus smaller 5 wire case plug in with a controller from Edward Lyenn along with a cycle analyst.
    I installed Edwards controller ( plug and play) and cycle analyst and new twist grip throttle last year at the end of our biking season and had a dozen good trouble free rides.
    This year I charged up my battery and checked my connections, which are not A grade I admit ,while I am learning this whole process. She started up fine but as I rode into town I heard/ felt something and the power was no longer…. still made it into town to pick up the kids under Dad power.
    With the 54 V set up and 48 V hub you do feel it kick in and out of power if you are not smooth with the throttle under normal use ( the cycle analyst has greatly helped this but I still need to figure out how to set it up in the most efficient way for my system). I felt maybe it wasn’t up to a full charge and just died but but after recharging my battery, now at 54 V at the power end going to controller, and seeing this power also on cycle analyst as well as throttle movement causing a reading on the display I would like to know how to check if I am getting power to the hub before pulling off the hub and looking inside. Any tips? Thanks !
    Donny

    • Sounds like you have a pretty good handle on getting this figured out. If that is a geared motor, the gears could have failed. Checking the output from the controller takes a special meter.
      I can’t say I have a perfect solution for you—just follow your instincts as you look for the problem.

    • Art Torres says:

      I have a small electric scooter, dont know the brand but it wont run if the headlights are on. Runs fine with the lights off.

      • Headlamps are usually LED—which means the polarity must be right (there are only 2 wires so fixing that is easy). I know having it wrong won’t let the light come on—yet I haven’t seen it making the bike (scoot) not run.

  20. Nathan says:

    Hey just wondering if u can help me. Just bought a 2010 daymak Classic. I charged it and hopped on to ride hit the throttle and it didn’t move it only chugged is this the battery or the motor?

    • Well Nathan, hard to say from such a small amount of information. I would think you followed all the info in my pair of articles and know what your battery voltage is and have checked all the wiring for issues—and much more. Give me the results of all your tests and maybe I can help.
      OK? Turbo.

      • Nathan says:

        Honestly I think it’s the batteries looks like someone left it out in the cold as they are bubbled and leaking. I didn test the voltage as I don’t have a tester for that or the wiring as I don’t have the tools to get to any of it. All I know is the horn (thought it sounds weird) works the blinkers work and the headlights do not neither do the leds on the speedometer. Every time I turn the bike on it says it’s full charge but when I hit the throttle it just chuggs like jerkin forward every few seconds instead of just going. I believe it is the batteries not sending enough power to the bike for the motor to work properly I just know batteries are expensive and I don’t want tospend that kind of money on
        the wrong problem.

      • If the batteries are bulging and leaking, you have no choice but to replace them. Sounds like they are SLA (sealed lead acid). I tell people to stay away from them and use only lithium batteries nowadays. Yet they are inexpensive compared to the lithium (during the purchase) but cost more in the long run (they don’t last long—perform poorly–and are very heavy). Switching to lithium is more involved than just buying them too.
        It will be hard to evaluate the bike and if there are other issues without some good batteries.

  21. Haxar cen says:

    I bought an e-bike system, and company combine it on my bike.

    But weird problem occurs and they can not solve this problem.

    Let me give you some instructions about the system.

    Battery = 48V, 11.6 ah downtube battery (samsung cells)
    Lcd and controller = moped electric bicycle scooter LCD display & controller set 24v36v48v
    Rear Hub = 500W

    First of all I put the battery on its housing. Then push the power button and power button light is on (blue). Then when I push the “system on” button on LCD display, fuse blows. On this point (blue) light is switched off.

    After that, I get off the fuse about 5 seconds and re install it. Then push the “power on” button.

    Even as the blue ligh is on, I put the battery on its housing. Then I push the “system on” button on LCD display…. BINGO! It starts…

    I can not find any solution. Please help me, thanks.

    • Very unusual indeed. I would make some draw tests on the system to see what kind of amps are being used—and if that is normal or excessive. What size fuse are we talking about? 40 amp?

      • Haxar cen says:

        24V is written on the FUSE. I am wondering about the battery software, BMS system. Also i replace smaller hub, which is 250W. But the result is the same.

      • Haxar cen says:

        Also my hub watt between 500 and 750. There is nothing written on the product, I took the information from seller.

        I am wondering BMS system but I do not have any programme to adjust BMS settings on PC.

      • Haxar cen says:

        Is there any solution?

  22. Ray says:

    hi there my sakura electric bike has been sat for very long and i just went to charge it and the charger shows full charge but the bike shows that the batteries are dead however the horn and headlights do work

  23. Sounds like you have some work to do. Just follow all the steps outlined in these two articles and that could help. Once you have done that, relay your findings here and only then can I help you more. If it isn’t something you can do, get the bike to an expert E-bike mechanic to get things figured out. Good luck, Turbo.

  24. Ilias Anastas says:

    It is my third day since I installed a 750w motor with a 48v13.6ah dolphin Panasonic battery, on my specialized bike and all worked fine. Today after 8km ride I lost all the power, and the display was out. I try to power on and no respond on the display The battery it’s full charge. All the connections are check okay, but I can’t find where the fuse is located. I will appreciated any help.

    • Some voltage and continuity checks are in order. Most E-bikes do have a fuse in the battery, and they do fail for no reason occasionally, yet usually if they blow you need to locate the reason why. If the battery has the correct voltage to its output connections—then I would suspect a bad connection somewhere in the system.

  25. Rodrigo Da Silva says:

    Hi!
    I loved reading your articles..great stuff!
    I recently bought a second hand Kenbay mountain bike. When I took it home for a few days the battery was ok..the pedal assist would work fine on a flat road. When I took it to work I climbed a hill and the battery died on me. I charged it (I think) and now it doesnt work at all. I put the key in, turn it on and the lights on the handlebar display flash full but when I start pedaling the lights go to empty.
    At first I thought it was the battery but I noticed that when I turn the key harder the lights turn on and stay on – when I let go of the key the lights go to empty again. I tried holding the key and pedaling and it worked for a few seconds and then it died again.
    I am seriously thinking of getting a new battery but now I am not sure if there is something wrong with the battery, something with the key or something with the bike itself. I checked the ECU and there was one single white cable unplugged – I plugged it again but it didnt make any nnoticeable difference.

    Do you have any idea what might be going on? I would really appreciate any help 🙂

    P.S. The charger that came with it is pretty banged up as well – so I’m not certain that is charging the battery properly.

  26. rob herring says:

    Raleigh Forge Crossbar 48cm Silver I’ve recently bought this bike took it out on its first ride and its cut out wont switch back on bike is fully charged the display system just wont switch on

  27. Just roll it back down to the dealer for a repair or exchange. A good E-bike dealer will even pick it up and redeliver it back to you afterward the fix. An even better dealer will lend you a replacement E-bike during the fix. They have your money and you should be able to ride every day (during the warrantee period at least).
    Turbo.

  28. rob herring says:

    Hi Bob, I’ve recently bought the Raleigh Forge. I’ve had issues from get go. I rode it for 20 minutes and display went dead.
    I sent the bike to shop, they said it was issue with fuse.
    I’ve now have the bike back. Fully charged, it lasted week. I’ve charged battery back to full, but range hasn’t changed, still only saying 0-20.
    Do you still might be issue with fuse? Thanks.

    • Almost always if a fuse blows, it does it because of a problem. On a rare occasion the fuse will fail for other reasons. It sounds to me like the dealer sped through the repair and didn’t check the bike well enough to make sure it is defect free.
      I would press them to get it right—-ask for a replacement—or a refund so you can get a bike that works well for you.

  29. Pete P says:

    I am having a weird issue, my charger says battery is full after about 1 hour of charging. I check the voltage and it’s around 52.3v (4 sla’s around 13v each). I can only get about 3-4 km’s on the bike before it says it is dead, but when i check the voltage they are only down by very little. 51v or 12.7/12.8v on each. And plugging it in, after 40 mins to 1 hr it’s full again. Please let me know of where you think I should troubleshoot next and thanks for all the great info on this page. Very helpful.

    • Try checking the voltage of each battery separately—maybe one has gone bad. Plus if those batteries are 1-2 years old that could be an issue too.
      You can charge each battery separately with a automotive charger to see if that will help. Could be the charger you are using, yet I would suspect one or more of the batteries.
      Remember it is best to replace them all together if you can. That is always best, even if just one has gone bad.

  30. Kurtis B says:

    Hi I have been having an issues with my electric bike which is 36 volt battery pack and it uses 3 12 volt lead acid batteries. I have recently replaced my batteries to new one and I have had no issues in till the other day when I charged my batteries and put them in the bike the next day and when i plugged the plug that connects the battery to the bike it had smoking coming out of it so i quickly unplugged.
    I have changed the circuit breaker and changed the plug on the battery pack and it keeps smoking.
    Any help would be very appreciated.

    • Sure doesn’t sound good Kurtis. There has got to be some wiring issues—bare or shorted wires (especially now)—or some type of overload going on. Not much I can do for you from my keyboard—other than suggest taking a really good look at all the hook-ups and doing some voltage and continuity testing.

  31. Robert says:

    I have a battery that wasnt used for the past 2-3 months due to a failed motor. The battery is a 48v 18ah Li-Po battery from conhis motors. After replacing the motor and charging the battery, I tested the battery (it has a self testing button and a key which allows me to turn on and off the battery itself) which showed that it was fully charged and the rear light (part of the battery iself) came on. Once I connected it to the bike and turned the battery back on, the self testing button on the battery wouldn’t work nor the motor itself. I, of course, haven’t been able to test the new motor since this is my only battery so I am unsure if the battery or the new motor is the issue.

    Any ideas or other things I should check?

  32. Sure—1st up is checking the battery voltage. Before that, why not try reading both articles in full. I would think your battery is fine, and the trouble lies in the wring, connections, or the ECU.

  33. Maz haigh says:

    I have an Aspen Izip I purchased second hand. It has worked, though would cut out sometimes while going uphill (if I kept pedalling it would restart then I started to experience other problems). I purchased a new battery (as part of a complete kit) (then I started to lose power on the flats). My friend changed the motor for the new one and I noticed it started running slower and was harder to pedal eventually the power became non existent. He then changed the rest of the kit over (though he did not fit the sensor on the pedal (he rewired in the old one to the new system)It reads full battery then as soon as I pedal it it cuts out and stops working, (same problem as before but way worse). We have changed all the electrical parts. I have two batteries, both read full on the charger. On the bike one reads full. Soon as I pedal it’s flat and no power. My old battery does not register any power at all. Please help. Is it the pedal sensor? Love my E-bike, can’t afford a new one.

    • Maz, what a list of issues. These old Izip E-bikes used a external motor that had motor brushes that would wear out as the years went by. I think that was—and could still be—much of your problem. New batteries going dead right away? That is weird too.
      I suspect some or all of the replacement parts were used and just as bad as the ones you are replacing.
      That is an old school bike—it should be able to be fixed—yet the newer ones with brushless motors and lithium batteries are sooooo much better.

  34. Robertas says:

    Hello. I have a problem with my new bike battery fuse on this one http://el-sykkel.no/produkter/scoot-el-sykkel/dreamspin-scoot-48v-el-sykkel—2016-modell.aspx . Whenever im going up the hill the battery fuse shuts down.. i have checked the battery voltage its showing 50v, i think it is normal, all the wires are fine.. i cant find a problem why it could pop out.. maybe it has to much pressure climbing up the hill? Or not powerfull enough? I have last idea to open my battery and maybe clean up everything in there, but dont trying to do that until i could get better and mofe information what could be wrong.. everything else is working find..

  35. Could be the wrong sized fuse (amperage rating). You didn’t mention what size it is. Have you checked with the manufacturer about that?

  36. Dan says:

    Hoping you can help,It seems my battery is charging to full potential on the charger,when the battery is plugged into the speed control the digital read out shows full power but when I ride 4-5 km on level ground battery meter shows dead .I have checked all the wires and contacts and seems all is well .I have checked the wheel and there is no binding. I am not sure if I have some bad cells or the charger may be defective , still peddling ,can you help?

  37. Babis (from Athens/ Greece) says:

    Hello my friend!
    At last days comes to my hands a used electric scooter, 48v/250w. It has one problem of condition. When I open the throttle the wheel turns very slowly with out power! (with the bike on main stand) and the voltmeter on panel, show zeros (0) from full. When the bike on road the power can not start, but I can feel it try to go.
    Bateries show 48.8 volts with external multimeter, and the charger gives 52+ volts.
    -Where or what is the broblem ?
    Thanks for your time!

    • If it has a brushed motor you can feed full battery power directly to it. If the motor runs fine then suspect the controller—or wiring.
      If it has a brushless motor then I would still suspect the controller. yet wiring, and other factors could be issues causing the problem.

  38. Pete P says:

    Hi Bob. What are your feelings toward the scooter-style bikes? I notice on your blog you don’t test or really mention them anywhere. One would assume you don’t find them to be e-bikes other than in name only.
    Just wondering.

    • They sure aren’t my thing. The ones with pedals to just meet the minimum legal part for E-bikes—I call fakeo E-bikes. I have shown them on my You-Tube, but not for the reviews.
      I have ridden electric scooters—they are fun, quiet and smooth.
      I mostly like bicycles—can you blame me?

      • Pete P says:

        I don’t blame you one bit. I am waiting on a welder to make the foray into custom frame-building. I’d like to do a recumbent-style ebike or a three wheeler. You do a great job here, keep it up.

  39. Mathew says:

    Hello Turbo Bob,
    This is a great Blog, and so helpful!
    MOTOR CUTS AFTER 5 SECS.

    I have a Prodeco Phantom X2, 36 volt 500 watt motor, about 3 years old with daily use of 10 miles.
    The motor works fine except after 5 seconds of pulling the throttle it cuts out, then if I turn the throttle back to zero and open it again it runs for another 5 secs, I can ride all the way home like this.
    I pulled the hub and checked the Hall sensors and there was physical damage. I tested the kill switches in the disk brakes, front works fine but the rear doesn’t work at all. The throttle works fine, battery fully charged, reads 39 volts. Is there any way to test the Controller or the BMS in the battery? I hate to spend $75 on a controller if it is not needed.
    Please any help would be appreciated.
    Keep up the good work,
    Thanks Mathew

  40. robert gibbins says:

    Hi Bob got a bit of a problem. I went for a ride, no probs, stopped at lights and no go. I have power, just charged, all lights working, it just wouldn’t engage into gear. It was working perfect up to then.

  41. Bad news. These two posts list pretty much step-by-step a way to make most of the needed checks. I assume you fully read it all and followed them all. Once you have, let me know the results and then maybe I can be of more help.

  42. Ashly says:

    I am a 30 year old woman and I just wanted to know where I can talk to someone over the phone just to help me figure out what’s wrong with my bike I don’t know where else to go

    • Couldn’t be easier—just call the shop you bought it from. They are almost always fully ready to talk to help you out.
      Bought it online?—bummer. Still the company you got it from should have some way to be contacted. Or just call the closest E-bike shop to you.
      There are online sites to help with E-bikes…. Endless Sphere for example. They have a web forum and a Facebook page.
      Are you having a specific problem?

  43. rene gloria says:

    hello there, I got a problem with my e bike, if I turn it on, the LCD monitor at the lower part indicates box with letter ECU. and the e bike will not run even in a full throttle. the speedometer remains OO even in full throttle engaged. but in center stand and help the wheel works the speedometer will register its rotation. all parts functioned but it will not running. can you please give some advice please?

    • Rene, that is interesting. I am thinking maybe a wire or connection is affected when the bike is on the ground (sounds weird, but check closely for that). Also, it could have to do with the motor not having the power to run the bike—but enough power to freewheel with no load.
      In many ways it sounds like the ECU (controller) is really the issue—or the connections between it and the motor sensors (or the sensors in the motor itself).
      After a good wire and connection check, I would probably suspect the ECU and replace that.
      Make sure to read and follow both articles and maybe it is something simpler.
      Good luck, Turbo.

  44. Murray Howkins says:

    Hi Turbo Bob,
    Thanks for all the excellent tips. I read through these but don’t see my issue yet. I have a Chinese special second had (ie no shop to go to) 36V with 800A brushless motor bought originally from LA Shop a couple of years back. I have had issues with wire corrosion which I fixed and it ran very well for a week or so. Yesterday I hopped on the bike and ran it with no problems. I only went about 4 miles, nowhere near a full charge, but charged the battery anyways – not sure this matters but the only thing done differently. This morning, the bike has power but the wheel only chatters (tries to turn but stops and repeats – like vibration); it won’t turn. Mechanically there is no hang up. Should I be looking at motor, ECU or wiring? I did try disconnecting the battery and reconnecting, but not disconnecting the motor from the ECU – which you flagged but said hadn’t been effective for you. It was wet riding the first couple of miles, but it sat for a couple hours before I rode it again dry and it was fine. ECU is well covered so can’t get wet.

    Thanks

    • I think we can blame the throttle on this (if you actually have one on your E-bike). The do dry out on their own or with the help of a hair dryer. Some wrap them with plastic wrap on wet days. Sounds like it is working fine now.

      • Murray Howkins says:

        Thanks,
        In fact the problem continued with the motor turning over but with no power. Based on your comment on drying out the throttle, I took apart the wiring and put it back together. That was the trick, although I didn’t fix or clean anything. I left it for a week to dry out, but it required taking apart to solve the issue. Maybe salt residue or something got loose? I don’t know.

        In general though, I am still unsure what to start with when trouble shooting. In my case, so far it has always been wiring, but are there specific signs that you consider which would generally point to the controller rather than wiring? And noise is the primary pointer to motor issues?

        Thanks

  45. JimmyH says:

    Hello, Bob!

    I have a tricky problem with a second hand electric go kart, witch I bought from a friend of mine. He told me it has some little failure, but I took the risk and now I have come to a dead end with my studies with the kart.

    Here it is in a nut shell;
    System is 48V 1000W brushed motor kit. They seem to use this kit in electric scooters, too. Battery voltage can be up to 54V (SLA batteries). The battery pack was recently replaced by the former owner. I have tested all the separatre parts; throttle, brakes, key switch etc. and everything seems to be right. Everything but the voltage in red – black wires from ECU to the throttle. It’s usually 0,78V or sometimes 1,67V when the trhottle is not connected to the terminal. This confuses me, because I have understood that the voltage here should be 5V.

    I tested the throttle with a 4,5V battery, and it worked correctly.

    I have tested this with three different ECUs and two different throttles, but the voltage from ECU to throttle is always well below that 5V needed.

    Another notice I have made, the voltage from ECU to motor is constantly about 9,8V, when key swtch is turned on. The motor does not turn or make any sound. Anyhow, I usually do these testings without connecting the motor to the system, just for safety reasons.

    Last time I did do the testing, there were only the battery pack, fuse, ECU and key switch connected, and still the result was the same; 0,78V measured from the ECU throttle terminals (red, black) and 9,8V measured from ECU motor terminals (yellow, blue).

    As far as I’m concerned, the battery pack or it’s wiring is the only thing that can cause the issue here, am I right? Or is there something, I’m doing wrong here? I just think I’ve tested everythin I can imagine.

    I would be very pleased, if you could help me out here.

    Thank you in advance!

  46. honda_boyz@hotmail.com says:

    I am out of idea’s. The LED Throttle power on show the status fully charged and the battery built-in LED indicator shows fully charged when pressed. But the Ebike Motor won’t turn?

  47. sharon says:

    hi l have an e bike it not working battery charge fully but where l charge my bike up l lost the cover would this be the reason why

  48. There could be many reasons for this—did you read both articles and follow all the ideas?

  49. I would sure need more info to help you at all.

  50. Zach says:

    Hi Bob,

    I bought a bafang mid drive kit from Luna cycle. Installed it myself and it work(ed) great. Love it!
    When I ordered the kit I got brake levers with power cut-off sensors. I have nice new disc brakes and components so I never installed these and the wires for the sensors are not connected. Now my battery is randomly dying even when I know it’s fully charged. Could this be related to the uninstalled sensors?

    Thanks!

    Zach

  51. That shouldn’t affect it at all. I would suspect a bad battery—or possibly a wiring issue.

  52. Jacqueline Conway says:

    I have an old gio ebike 48 volt battery. Battery is 2 1/2 yrs old. Charger is only a month old. The battery seems to losing a charge rather quickly. Won’t hold charge for long. Could the battery be no good or is it a bad connection? Problem just started happening, any ideas?

    • Does sound like the battery is the problem. If it is a SLA (sealed lead acid) battery then you got a long life span from it. Even if it is a lithium battery, that is getting fairly old. They should last longer, but not always.
      I would do some voltage tests on it when fully charged and when discharged to see if that answers any questions.

  53. Gary says:

    Instead of my bike going it just makes a grunt noise coming from the motor when I first turn it on and ran it on the front it was running fine but was going in reverse I turn the tire around and now it just grunts please help

  54. Sounds like the controller could be the problem. Then again from this minor description it could lead to most any of the components. You turned the motor around? Why? Going backwards?

  55. Mike Nadeau says:

    Hi I am new to e bikes and am trying to repair an electrical issue. the motor gets power and seems to run fine with a good speed. My issue is none of the lights work, the head light rear light or break light, the flashers and even the horn wont work. I was wondering if there is a quick fix for this and where I should look like maybe a fuse box or relay that could be easily replaced. I almost forgot it is an EMMO and that is about all I know, if it helps I believe its 48 volt. Thanks in advance. Mike completely lost and desperate for a cost effective fix, can you also e mail me your reply, cheers

  56. None of the bikes I deal with have all that stuff—normally just the scooter types with the fake pedal systems.
    Even still, some quality time with a VOM (with a person that understands electricity and how to use a VOM) should be able to find the issues and fix them. Good luck.

  57. KRISHNA says:

    Hello,Sir, I am using electric bike with 48 V batteries and 250 Watts motor, 2 years it worked fine, but suddenly, yesterday, when i started the bike, vehicle not moving, I have put the stand and raised the accelerator, then the back wheel is moving slowly, may be 25% speed of actual rotating. There is no pick up. would you please suggest me any trouble shooting solution. Thank you sir.

    • Motor or controller would be the quick guess. There are other possibilities—including bad connections in the wiring. This is assuming the battery is strong—I am sure you made the needed voltage tests on it. If you are using SLA batteries, then they would be the prime culprit.

  58. RC says:

    Hi Turbo Bob and crew. I am building a ebike 3-wheel trike using a 48v 100w motor and a 48v 30ah LIFEPo4 battery. when I connected the power to the controller and nothing else connected it seemed to blow the controller. 😦 am I missing something here? I thought the ah is just for how much power it will hold in order o go longer on a single charge.

    The products I purchased are below for reference.
    Motor Kit
    https://www.amazon.com/AW-Electric-Bicycle-Cycling-Controller/dp/B00YBW9TD2/ref=sr_1_13?rps=1&ie=UTF8&qid=1503393581&sr=8-13-spons&keywords=48v+hub+motor+and+battery&refinements=p_85%3A2470955011&psc=1

    Battery
    http://sun-ebike.com/48v30ah32650-lifepo4-battery-with-5a-charger_p0035.html

    Am I missing something here? Any guidance and advise would be greatly appreciated as I am trying to complete the build in the next few days.

  59. Shane Dempsey says:

    e bike throttle works but wheel won’t spin just vibrates

  60. Normally I would suspect the controller—the sensors in the motor—or the sensor wiring for an issues such as this.

  61. O says:

    I was riding my e-bike without trouble a few days ago. I remember stopping at an intersection and attempting to re-accelerate but the bike wouldn’t move. I tried using pedal-assist to at least get the motor going and nothing. Now the bike won’t move on it’s own if I hit the throttle. The battery was fully charged at the time. My LED Battery indicator, front head light, and horn all work with the battery on. The motor is the only thing not working. Could it be the ECU or the motor, or both?

  62. Ralph says:

    Hi, I’m helping a friend who’s having issues with an e bike. It stopped working, so we renewed the throttle, the ECU and took away all of the sensors that we think we don’t really need.. To be clear disconected the brake sensors, the paddle assist, there no hall sensors connected ore anything like that. Now we only have the cables plugged for the throttle(3wires) the display(3wires) the fully charged battery(2wires) and the motor(3wires) the bike seems like it want to move forward but it’s not move more then an inch an all speeds. Is there something I overlooked in this situation, help would be much appreciated thx

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