Motor stopped working, need some help.

While riding in the rain, my motor began to cut out and then start up again with no change to the throttle. The periods of no power became longer and longer to where now the motor is off more than it is on. I wasn't able to go above 10 mph. Here are my specs:

1000W DD generic rear hub motor
KT LCD 5 controller
2 6S lipos in series.

I only have just over 100 miles on the motor.

One thing that did happen a couple of days ago is that while taking the bike down the stairs into the basement, the bike rolled off of the stairs, causing rhe rear wheel to drop about 4 feet to the ground. I then noticed the sound of metal bouncing around for a couple of seconds after rolling the bike forward. Not aure ifnit came from inside the motor or not.

Any thoughts on the issue or the correct next steps? Thanks.

1: Disconnect the battery and make sure it is not going to short out from the moisture.
2: Let the bike sit for a few days to make sure it drys out.
3: Hook the dry battery to the dry e-bike and see if it works.
4: Report back with your results.

Well, it could be the drop did something. but the most likely thing is the throttle got wet, or just the throttle plug. Intermittent cut outs really point to a bad contact in some plug or other.

Where is your controller located? does a wheel spray it? Undo all the plugs and dry them out, then try it. While its drying, check every inch of wire for cuts or nicks, you might have bashed the wire coming out of the hub on that drop.

dropped the bike and a metal sound on a new build. id be looking at the rear disc brake area and the motor cable to see if it got nicked, id also check to make sure the bolts holding the side covers on are tight. if the side covers weren't tight/tight, tighten them and if sound persists id open up the motor and see if theres some metal shavings inside by the magnets

I will take a wild guess that there were no problems at all BEFORE you dropped it, and the problem started fairly quickly the very next time you used it, AFTER you dropped it? This detail should be explained, at least you DID mention the likely cause of the problem. OR, did it work OK for an extended time after the drop?

These sounds of metal rattling about, are we talking teeny-tiny softly tinkling noises, or louder, sharper noises such as would be made by a fairly substantial piece of hardware? What happens if you flip bike over, rotate wheel, slow, fast, whack the tire hard to dislodge possible stuck piece, repeat, repeat, and repeat again, can you create any more noise? Any leftover parts anywhere around the scene?

As mentioned, most likely a nicked wire or damaged connection, possible water ingress in same. Carefully examine all wires and connections. If noises in wheel are repeatable, then opening motor likely required. Also check soft-bodied Lipo for any visible issues, check voltage and if possible, load test.

Edit to add: Check your spokes carefully. Possible red herring to eliminate.

Think about how hub motors are made inside. I'm betting that noise is outside, spokes a real good guess. But a nicked wire might run fine till it got wet.

The controller was in a triangle bag that does tend to collect a small amount of water. The bottom of the bag was wet to the touch when the issues began. I was also not using fenders, so a small amount of water and salt spray may have reached the controller through the inch or 2 of open zipper on the frame bag.

So I disconnected everything after posting. I just reconnected, 2 days later, and the issue persists. All of the cables look good. I turned the display on and off a few times. A single time, I got "no 3" message on my KT LCD5, which I believe is a hall sensor error.

I checked for loose spokes and they are all tight. The bike ran fine before the drop and for a couple of days afterwards and I am no longer hearing any metal noises, so I am leaning toward water ingress. I disconnected everything again and will let it sit for a few more days before trying again.

I should note that sometimes I can get a couple seconds of continuous motor power and other times, its only on for less than a second before it cuts out.

Thanks for the help everyone.

Do throttles commonly fail? Is it a good idea to have a spare on hand? I may just order another if it is a part that will likely need replacement soon anyway.

Throttles may go bad after a shower as most are really not water resistant let alone water proof. Never hurts to have a replacement on hand and easy to check with changing the part. Especially with their low cost.

Or if your like me and need proof before buying something, you could check electrically with a meter as follows...

For a hall sensor throttle, of the 3 wires, two are for 5vdc, input and ground. (typically Red and Black, but not always! verify first with your wiring diagram)
The last wire will be the hall sensor variable voltage output. Which should vary ~1vdc to ~4vdc, closed to wide open throttle.

Don't confuse this hall sensor with your error code. As that would pertain to your hall sensors in the motor.

For more detailed information on testing procedures and operation, please read this thread...

Guide to Hall Sensor Throttle operation, testing, and modification.


Regards,
T.C.

Yes, throttles fail fairly frequently and Yes, they are particularly susceptible to water problems. Having a spare is a very good idea.

However, in my experience (twice) and what I have read they usually recover after having time to dry out. You may want to try some compressed air, remove the throttle from handlebars and dry thoroughly, place in the sun for a while, etc.

In your initial problem report you notice that the problem increased over time, presumably a single ride. Roughly how long was this, minutes, hours, continuous ride or a stop in the middle? Also, was it continuously raining or did the problem continue to get worse after the rain stopped, if so, for roughly how long in minutes or hours are we talking here?

Now, when you are testing - is the bike, other than the throttle, ABSOLUTELY STABLE AND UNMOVING, or are you sitting on or riding it? A nicked wire or bad connection can easily be bumped, pulled, vibrated etc into "good" or "bad" position with the slightest motion.

Gonna harp on the wire and connection issue here. This is, BY FAR, the number one cause of problems, MOST ESPECIALLY the kind you have right now, very much more so after a major impact of some kind. Also, these are frequently found on the second or third pass of inspection. The pins frequently get loose in their housings, must be physically checked, not just visually.

+1 on checking all connections if the bike is now dry, and has been for a few days.
Unplugging connectors and making sure the pins are all properly in place is a good idea.
Make sure your phase wires are all connected.

If that does nothing, you now need to go through your system to attempt to isolate the problem.

Start with the easy diagnosis:

(If you have e-bike cutoff brakes) make sure your brake cables are properly adjusted so that the brakes are not cutting off the bike.

Make sure any throttle cutoff buttons are not pushed.

Make sure your battery is fully charged and balanced.

Then go to the harder stuff:

Test your throttle like this:https://www.ebikes.ca/documents/ThrottleTesting.pdf

Test your motor halls like: https://www.ebikes.ca/documents/HallSensorTestingFinal.pdf

Test your mosfets: https://www.ebikes.ca/documents/BlownMosfets.pdf

I usually keep an extra throttle on the shelf. I tend to go through at least one per year. Keeping a spare inner tube and even a
spare controller on the shelf is also extra protection from being unable to ride your bike for a period of time.

AngryBob said:

In your initial problem report you notice that the problem increased over time, presumably a single ride. Roughly how long was this, minutes, hours, continuous ride or a stop in the middle? Also, was it continuously raining or did the problem continue to get worse after the rain stopped, if so, for roughly how long in minutes or hours are we talking here?

Now, when you are testing - is the bike, other than the throttle, ABSOLUTELY STABLE AND UNMOVING, or are you sitting on or riding it? A nicked wire or bad connection can easily be bumped, pulled, vibrated etc into "good" or "bad" position with the slightest motion.

Click to expand...

The issue came on very quickly. The time difference from the first time I noticed the motor cutting out once to the point where it was off more than it was on, was probably less than 20 minutes. This was all during a single rainy ride.

When testing after the fact, I put my hand under the seat and lifted the rear wheel in the air while twisting the throttle. The front wheel stayed on the ground and the bike stayed pretty stable.

I verified that the brake cut offs were not the issue. I will double the check all of the connection pins tonight.

Thanks again everyone.

if you do open up the motor, make a mark where the cover plate attaches to the motor on the seam. my hs3540 only goes back on one way where all the screw holes line up. I did it wrong once and had issues with metal shavings in my motor.

the side cover has a bearing and where the motor cable,axle and bearing gets sandwiched ive had the sharp axle edge cut my wire so I filed the sharpness off and put a new motor cable on, then about a week later same thing but it was the cable getting nicked by the torx srews for the disc brake, another time I was pulling a trailer and felt the trailer kind of clunk when id regen and again when id take off kind of like a hydraulic brake actuator on a boat or car trailer but when I took the trailer off it was still there. the extra weight of the trailer actually flaired open the axle slot of the v4 torque arm and because my issues were always the motor cable/axle id made sure that cable couldn't move but then my axle moved and again the motor cable got nicked.

so whats my point? ive never had a hall issue, its always been motor cable. flip bike upside down give it a little throttle and slowly move the cable around to see if anything changes and if you have a disc rotor on the hub don't cut off your finger.

if you've never opened up a motor I remove all the screws on the disc side then I smash the other end where the cassette freewheel is onto a phone book while holding the tire. youtube it and watch your fingers unless you have the proper tools