Cyclone mid drive shuts down during acceleration

[saustin]

Hi I'm new to this forum. My father converted my bike with a Cyclone 3000w mid drive engine with a 72v 10ah battery probably 10+ years ago. It breaks constantly but its too much fun to give up on. I bought 5 engines and a dozen throttles before SickBikeParts went out of business and when i burn one out i just replace it and everything is fine.

Now i have a new problem that i cant figure out. While the bike is on the repair stand, the engine works flawlessly, i can accelerate using the throttle and get it up to max RPM. But the second i sit on it and try to accelerate (I weigh 200lbs), the motor will cut off immediately almost like its hitting some safety metric and trying to save the motor.

I have replaced the controller, the throttle, and the motor, everything works fine when in the stand but it still will not stop shutting down the motor *only* when i'm riding it. The only way i can "restart" the motor is by plugging in the battery to the charger. The battery reads 83v and is fully charged.

The only component I haven't replaced is the battery because i only own 1, which i suspect is malfunctioning.

anyone know what is going on? or am i screwed and i need a new battery?

I'm ready to finally give up on this Cyclone Mid drive build because parts are becoming more difficult to find but it has some nostalgia factor so i'm giving it one last shot.

 

[amberwolf]

Does it have a display or light that indicates whehter power is still on after the motor shuts off?

If there is no power at all after the motor shuts off, the battery is probably worn out and sagging under load, enough that at least one cell drops below BMS LVC and the BMS turns off the output. Plugging in the charger resets the BMS.

If there is still power but the motor doesn't run, the BMS is not turning off but the controller is probably hitting LVC because the battery sags so much under load (because of age, most likely).

Hook up your voltmeter to see what happens *during* the motor shutodwn, and if your meter is fast enough response, or has a Vmin Hold, (most only have a Vmax hold, if even that), you'll see the votlage sag if this is happening.

 

[saustin]

Does it have a display or light that indicates whehter power is still on after the motor shuts off?

If there is no power at all after the motor shuts off, the battery is probably worn out and sagging under load, enough that at least one cell drops below BMS LVC and the BMS turns off the output. Plugging in the charger resets the BMS.

If there is still power but the motor doesn't run, the BMS is not turning off but the controller is probably hitting LVC because the battery sags so much under load (because of age, most likely).

Hook up your voltmeter to see what happens *during* the motor shutodwn, and if your meter is fast enough response, or has a Vmin Hold, (most only have a Vmax hold, if even that), you'll see the votlage sag if this is happening.

Thank you! the throttle has a light and it does turn off when this issue happens. I figured it was the battery that finally died and the BMS was trying to save it.

I'm going to replace this Cyclone build with a CYC X1 pro Gen 4 with their 52v battery. Do you have any tips on the CYC? Hopefully it reproduces the same snappy torque as the Cyclone without the headache of constantly having breakdowns.

Thanks again for your response.

 

[amberwolf]

I'm going to replace this Cyclone build with a CYC X1 pro Gen 4 with their 52v battery. Do you have any tips on the CYC? Hopefully it reproduces the same snappy torque as the Cyclone without the headache of constantly having breakdowns.

I have no experience with it, but there are a number of threads discussing various versions of it, including some troubleshooting of problems you might encounter, etc., if you poke around.