E-Bike Power Goes OUT

[NarrackRider]

I have had a ViVi MT20 e-bike for over a year.I recently changed the worn out brake pads.

With a fully charged battery, I rode on throttle only for about a mile. After that, the power went completely out.

I turned the key on and off. The LED lights came back on. I twisted the throttle and went about 10 feet and the bike completely shut off.again.

Any idea what might be the problem?

Thank you!

[Jesper]

@NarrackRider

Disclaimer: I have no experience with ebikes other than their general components that are the same as on standard bikes. I do have electrical and electronic experience on systems that are not bike related.

First, is the bike under warranty? If so, stop doing anything and get it taken care of by the dealer/manufacturer. That would also apply to working on the brakes yourself (not sure if pads have any coverage due to normal wear and tear) since doing any work might void some or all of the warranty if not performed by an authorized shop.

Second, have you ever had any issues before working on the brakes? I assume, but correct me if I am wrong, that there is no wiring connected to the brake system, and/or you did not have to disconnect any wiring at all to perform the brake work.

Third, without knowing how many times you have charged that battery pack, your charging habits (e.g. running battery until nearly dead or dead, not fully charging the battery, leaving charger connected once fully charged, etc.), the conditions that the battery and the bike have been exposed to (e.g. high/low temperatures, moisture, vibration, dropping, etc.), and/or the expected lifetime/max amount of recharges of the battery it is difficult to say where the problem exists or what might be causing it.

There is a chance the something went bad and it has nothing to do with your working on the brakes and the problem arising is just coincidental. On the other hand you may have inadvertently done something to cause the problem. I suggest you take time to double check what you did just to confirm that nothing was affected by your working on it. I highly doubt that you caused the problem.
It only takes one cell in a battery pack to go bad for the whole battery pack to go bad so that might have happened and the timing with your repair was just bad luck.
I would assume the battery is bad first. If there is an ebike repair shop near you and it is convenient for you to take the entire bike to them; I would have them check your battery with a load tester (if they have one), but at least have them verify its charged voltage output. If the shop (or someone you know) has the same (good) battery pack, I would have them swap it out with yours to see if the problem is corrected or persists. If it persists then 99% it is not the battery.
If the battery tests okay, then I would assume either the motor, or control circuitry since that's about all that can affect motorized operation.
Is the bike power assist or is it throttle control only? If power assist design does that function work, but throttle only does not? If power assist works then I assume motor is fine and that there is an electronic problem.

I rue to give this advice, but contact (phone or email; NOT CHAT!) their customer service and see if they can help (I hope they prove me wrong). I can almost guaranteecl 2 things: 1) they really cannot provide any help and will just try to get you to buy spare parts that may or may not solve the problem (if you throw enough paint on the wall eventually it will be covered); 2) the problem is common for your brand/model and they are going to not want to deal with another repetitive issue and try to blow you off and blame it on you. DO NOT VOLUNTEER INFORMATION THAT YOU HAVE WORKED ON THE BIKE YOURSELF! If they ask just deny it.

You can try some dedicated ebike forums that might have more general experience or may have dealt with your problem on that specific model.

Good luck and fill us in on what the result is so that it might help the next person.

Edit: just out of curiousity: what did that bike cost and where did you pruchase it from (e.g. bike shop, brand's online site, general online ebike dealer, Amazon, etc.)?

[Electricbike1]

I had a similar issue with my e-bike where it would cut out suddenly. In my case, it turned out to be a loose connection between the battery and the controller. I’d suggest checking if the battery is securely connected and making sure there’s no damage to the wires. Also, give the battery a close look—sometimes, if it’s not charging properly or has a defect, it can cause these kinds of problems. If that all looks good, maybe take it to a shop to see if there’s a deeper issue.

[Talha]

(08-05-2024, 09:22 AM)NarrackRider Wrote:  I have had a ViVi MT20 e-bike for over a year.I recently changed the worn out brake pads.

With a fully charged battery, I rode on throttle only for about a mile. After that, the power went completely out.

I turned the key on and off. The LED lights came back on. I twisted the throttle and went about 10 feet and the bike completely shut off.again.

Any idea what might be the problem?

Thank you!

your e-bike is experiencing an issue with the electronics. Can you check the voltage drop when you use the throttle? your battery might be weak and in second case, maybe while changing the brake pads you somehow shorted any of the wires?

Check both cases