Odd problem with my ebike which has otherwise been running fine. I've got a charger now that shows voltage, and shows quite clearly that the battery "runs out" at about 3.6V/cell. Of course this isn't quite right as about 50% of the capacity is below this value (and it would also explain why a 14Ah battery runs out after about 15 miles). I have checked and C12 = 4 so it should cut out at the default value of 30V. Is there another setting I've missed? In the meantime I have set C12 = 0 (which should be 28V) so will see how that goes.

 

It's a 250W Bafang G010.250.D motor. Cells are Samsung 29Es so max stop voltage of 2.5V. I run it headless but I have a KT-LCD4 that I plug into the controller just to program it.

 

Many thanks

How old are the 29E's ?

Full charge voltage ?

Controller rating ?

Edited August 19, 2025Aug 19 by Nealh

old cells could sag below the cut off voltage under load, try running with the lcd attached and monitor voltage in real time perhaps?

I had two 29E 14.5ah batteries both were saggy at 6/7 yo but could still manage 20 - 40 miles dependent of PAS level/current used.

We don't know how the OP is using the bikes power or how .

One expects running it headless the power is defaulted to PAS1, so if using a speed switch power will be max amps demanded or equal to PAS 5.

Odd problem with my ebike which has otherwise been running fine. I've got a charger now that shows voltage, and shows quite clearly that the battery "runs out" at about 3.6V/cell. Of course this isn't quite right as about 50% of the capacity is below this value (and it would also explain why a 14Ah battery runs out after about 15 miles). I have checked and C12 = 4 so it should cut out at the default value of 30V. Is there another setting I've missed? In the meantime I have set C12 = 0 (which should be 28V) so will see how that goes.

 

It's a 250W Bafang G010.250.D motor. Cells are Samsung 29Es so max stop voltage of 2.5V. I run it headless but I have a KT-LCD4 that I plug into the controller just to program it.

 

Many thanks

If you had the voltage set to 48v instead of 36v, it would give you about 15 miles range if your battery was in good condition; however, in that case the display would show that your battery was half empty before you even started.

 

The LCD shows the voltage all the time by selecting that by a short press of the power button. You must temporarily install the LCD4 and see what it shows after charging and during your ride. That will tell you what's wrong.

 

36v after recovery isn't unusual for a completely run down battery. It's not half full. It would probably have been showing about 33v at the time of cut-out. Anyway, the LCD will show you exactly what's going on, so no need to guess, just watch and get the answer.

Odd problem with my ebike which has otherwise been running fine. I've got a charger now that shows voltage, and shows quite clearly that the battery "runs out" at about 3.6V/cell. Of course this isn't quite right as about 50% of the capacity is below this value (and it would also explain why a 14Ah battery runs out after about 15 miles). I have checked and C12 = 4 so it should cut out at the default value of 30V. Is there another setting I've missed? In the meantime I have set C12 = 0 (which should be 28V) so will see how that goes.

 

It's a 250W Bafang G010.250.D motor. Cells are Samsung 29Es so max stop voltage of 2.5V. I run it headless but I have a KT-LCD4 that I plug into the controller just to program it.

 

Many thanks

I had a possible similar problem once with a well used phylion battery (10S5P). The battery would cut out at about 36v. I opened the battery and got a very sweet smell,which is a bad sign. One cell was faulty (self discharge) and was dragging the voltage down on a single group of 5 parallel cells and causing the battery managment (BMS) to cut out the battery. I scrapped the battery.

Edited August 19, 2025Aug 19 by Sturmey