Limp mode on battery

[Bobj616]

What governs when a battery goes into limp mode? Is it the BMS or the controller? My new bike has a Bafang Ultra motor and 21AH battery . I have the screen set to read voltage rather than %. At somewhere around 46.5 volts it kicks in to limp mode and will give me around 400 watts of power compared to 1500 on a fresh battery. Yes ,it will get me home with plenty to spare but the point it kicks in seems really early. Any ideas where the problem might be or is is just something the battery hog Ultra needs to do?

 

[Chuy]

I am new to eBikes but was curious about this limp mode function. Quick research indicates this issue tends to afflict Bosch owners as a group. For others limp mode tends to afflict motors that overheat.

https://ebikes.org/safety/overheating-an-e-bike-can-be-a-buzz-kill-literally/

 

[Bobj616]

What I call "limp mode " is where the motor is restricted to a lower amount of power than the motor is capable of. It is to protect the motor from discharging too much. Neither my battery or motor are hot when it does this , it just reduces the amount of wattage available to the motor. It happens with both of my batteries at somewhere around 46.5 volts. My batteries come from different manufacturers and are slightly different capacities so I don't think this is a function of the BMS in the battery. I have learned to live with it . I can still ride around 50 miles before it kicks in and I have never had it shut down on me. I just need to be close to home when it happens.

 

[telfish]

Check in your settings to see if it's possible to change the limp mode to a lower number. I know on most bikes it's possible to change the low voltage cut off voltage.

 

[Bobj616]

I haven't seen anything like that in settings . I thought about trying a different screen/display but the DCP18 has a different connector (triangle shape) for this Ultra mid drive motor.