HELP.. ebike tries to take off by itself when battery is first turned on?

[Ging312]

Hi i was looking for some help. When i turn on/off my ebike battery sometimes the bike will try taking off. Ive tried looking online but im not good with words and couldnt find any similar issue. Not always but about 30% of the time. It only seems to be when first powering on the battery and sometimes when turning off. Ive even had it on PAS 0 to try stop it from happening as it once took off across my kitchen at high speed and was quite dangerous.Luckily ive never had an issue whilst riding but im becoming concerned as i only have normal disk brakes. No motor cut off brakes. If you guys need anymore info just ask and I'll do my best to answer. Thank you for any potential help or answers . It doesnt seem to be a throttle issue as like i say even on pas 0 where i usually get 0 power from the motor with the throttle applied it will still happen and the motor will randomly start up. I dont want to take off on me one day and i can't stop. Its a 3000w mtx conversion kit paired with a brand new 72v 60a triangle upp battery. Thanks again. Any help will be muchly appreciated.

 

[Ging312]

When the problem does occur the motor does stop after 5-30 seconds then works as it should. (Atm) but becoming more wary incase it gets worse. I would like to fix if possible i just have no idea where to start as cant seem to see anyone online with similar issues but i think ive just worded it wrong when looking.

 

[E-HP]

Was this always an issue, or did it start happening recently? If recently, did anything happen to the bike, like a wreck or got ridden in the rain, etc? It would be helpful to provide some more info on your controller, display, etc. You indicate that in PAS 0, the throttle should be disabled, but some controllers have settings to keep the throttle active even in PAS 0, etc.

 

[amberwolf]

The most common cause of this is the ground wire in the throttle having a poor connection, anywhere from the controller PCB inside it's case all the way to the throttle itself inside it's housing. Usually it is the connnector where the two plug together not being fully seated. Unplugging the throttle entirely would stop the problem in this failure mode, as a test.


FWIW, PAS0 is usually the throttle-only operation mode; if so it doesn't disable the throttle, only the PAS. If the throttle is causing the problem, then for systems like this, there arent' any modes other than turning power off that prevent it, until the ground wire (or other cause) is repaired.

 

[E-HP]

FWIW, PAS0 is usually the throttle-only operation mode; if so it doesn't disable the throttle, only the PAS.

If it's a KT controller, check the P4 and C4 settings.

 

[Ging312]

It could have possibly already have been an issue as i bought the bike second hand 2 months ago with no battery and only have had the battery and been using the bike for the past 4 weeks. Its never been in the rain and looked new when i got it. The guy said he built it a year ago. Not sure on the controller right now will have to get back to you. The display is an s830. Its all set up to throttle only. I have no pas sensors or what not. The 5 pas modes are just for different speeds. After the first time noticing it powering itself and taking off i thought if i put it in pas 0 everytime i turned it off it would help the situation as when i press the throttle in pas 0 the motor/hub doesnt move/engage at all. Yet it still gets random bursts of power out of nowhere but only upon turning on or off the battery. I saw about the ground wire in throttle but due to things ive mentioned i presumed that wouldn't be the issue but i will have a look into and change the throttle as i currently have a little thumb throttle and would like a twist.

 

[fechter]

You could try disconnecting the throttle and see if the problem still happens. You could also try disconnecting the PAS sensor (if it has one) and repeat the test.

 

[E-HP]

I saw about the ground wire in throttle but due to things ive mentioned i presumed that wouldn't be the issue but i will have a look into and change the throttle as i currently have a little thumb throttle and would like a twist.

It could also be a combination of issues. Some software glitch or setting that allows the throttle to activate under PAS 0, and a loose or poor connection on the ground wire. Have you tried unplugging the throttle and then turning the battery on/off so see it the problem still exists?

EDIT: Oops, what fechter said. :thumb:

 

[Ging312]

Its definitely not a throttle issue as if i dont disconnect the battery from my ebike/ when charging it tries to take off by itself also. Even when the battery is turned off power is still somehow getting to my rear hub and it tries to turn.

 

[Ging312]

Help!? if i dont disconnect the battery from my ebike/ when charging it tries to take off by itself. Even when the battery is turned off power is still somehow getting to my rear hub and it tries to turn. It also sometimes tries to take off when first turning on the battery to go for a ride. even without turning on the screen so dont think Its a throttle issue. Its a 3000w hub. 48-72v 60a controller with 72v 60a upp battery

 

[Adrian_]

Its definitely not a throttle issue as if i dont disconnect the battery from my ebike/ when charging it tries to take off by itself also. Even when the battery is turned off power is still somehow getting to my rear hub and it tries to turn.

If I understand this correctly, even if you disconnect the battery from the controller, it's still getting power and tries to take off? I'm not sure what kind of bike it is or how its designed but either there's a short somewhere that allows the controller to be powered in other way, or you're disconnecting something else. Pictures would be helpful.

 

[E-HP]

Its definitely not a throttle issue as if i dont disconnect the battery from my ebike/ when charging it tries to take off by itself also. Even when the battery is turned off power is still somehow getting to my rear hub and it tries to turn.

So did you disconnect the throttle or not??

 

[E-HP]

Help!? if i dont disconnect the battery from my ebike/ when charging it tries to take off by itself. Even when the battery is turned off power is still somehow getting to my rear hub and it tries to turn. It also sometimes tries to take off when first turning on the battery to go for a ride. even without turning on the screen so dont think Its a throttle issue. Its a 3000w hub. 48-72v 60a controller with 72v 60a upp battery

Did you try disconnecting the throttle as advised in your duplicate post?

 

[ZeroEm]

double threads of the same! HELP.. ebike tries to take off by itself when battery is first turned on?

 

[Ging312]

Its not a duplicate. Yes ive fixed the other issue this is a separate issue when the battery is completely off and charging

 

[amberwolf]

Its not a duplicate. Yes ive fixed the other issue this is a separate issue when the battery is completely off and charging

Then for us to help you with the new problem, you need to tell us exactly what has been done to fix the first one, because they are almost certainly directly related.

Because of this, the threads have been merged together, to help those helping you have all of the information necessary to help you.

Its definitely not a throttle issue as if i dont disconnect the battery from my ebike/ when charging it tries to take off by itself also. Even when the battery is turned off power is still somehow getting to my rear hub and it tries to turn.

That means your battery's power switch either:

--doesn't work and/or is not connected

--isn't actually the power switch but is for something else you're not aware of

--doesn't actually disconnect the battery but just turns the BMS off, *but* the BMS's FETs have failed stuck on, so that even when it is off it cannot disconnect the battery from the system (a common failure)

It will require opening your battery casing to do visual and electrical testing to find out which of these problems it has (it can be more than one of them).


This, however, is an *additional* failure, not related to the taking-off-by-itself failure.


The TOBI failure is almost certainly your throttle wiring (a bad ground connection anywhere between the throttle sensor inside the throttle, and the ground pad for it inside the controller). If you have not disconnected the throttle plug from the controller to test for this, or otherwise disassembled and tested throttle, cable, connectors, and controller to verify all ground connections inside them, you cannot know that it is not a throttle issue.

If you won't perform the troubleshooting steps we suggest based on the info you provide, then it is going to be VERY hard for us to help you.

Also, if you don't provide complete information about everything that happens during the testing, and about the problem(s) you're having with it, *and* everything you change or fix, we can't suggest correct or complete troubleshooting steps.

 

[E-HP]

Its not a duplicate. Yes ive fixed the other issue this is a separate issue when the battery is completely off and charging

You said that in your other thread

Its definitely not a throttle issue as if i dont disconnect the battery from my ebike/ when charging it tries to take off by itself also. Even when the battery is turned off power is still somehow getting to my rear hub and it tries to turn.