My bike went dead half way thought to work

[patpatbut]

Cycled to work as usual and the LED panel went off about 7 miles.

Could turn on the LED panel again but it went off 3 seconds later.

I charged to full at work now and measured the voltage should 42.6

Tested it out again and it went 500 metres and it went off again.

Do you know what happen to it? If the cell is not balanced it wont should usual 42.6v right?

Would that be the controller problem?

Background:
This battery pack 36V12AH lifepo4
36V12Ah LiFePO4 Alloy 03-CASE EBike Battery With a Carrier Rack - BMSBATTERY

KU65 controller

Thanks
Pat

 

[Deleted member 4366]

Sounds like an interrupted power supply to the controller. First check your battery connections - everything between the battery and controller. That includes the key-switch. They often give problems due to bad soldering. Sometimes the solder on them is just sitting as a blob, and isn't actually connected. Try re-soldering it, using plenty of time to heat up the whole joint.

 

[patpatbut]

Sounds like an interrupted power supply to the controller. First check your battery connections - everything between the battery and controller. That includes the key-switch. They often give problems due to bad soldering. Sometimes the solder on them is just sitting as a blob, and isn't actually connected. Try re-soldering it, using plenty of time to heat up the whole joint.

Thanks. I will check the connection when I get home.

I checked voltage now it is 40.3v (off from charger after 4 hours) Is it too low?

Thanks
Pat

 

[amigafan2003]

I checked voltage now it is 40.3v (off from charger after 4 hours) Is it too low?

Yup - sounding very much like a duff cell in your battery which is tripping the low voltage protection circuit.

 

[Deleted member 4366]

Thanks. I will check the connection when I get home.

I checked voltage now it is 40.3v (off from charger after 4 hours) Is it too low?

Thanks
Pat

You do get a bit more voltage variation with LiFePO4 batteries than LiCoMn, so I don't think that it's anything to worry about. You normally charge LiFePO4 cells to 3.65v, which would be 43.8v for the pack, but there's not a lot of charge difference between 3.3v and 3.65v, so if you leave them they often settle back to 3.3v, which would be 39.6v for the pack. Most of the discharge happens between 3.3v and 3.1v. If you had a LiMnCO battery 40.3v would be too low.

 

[patpatbut]

You do get a bit more voltage variation with LiFePO4 batteries than LiCoMn, so I don't think that it's anything to worry about. You normally charge LiFePO4 cells to 3.65v, which would be 43.8v for the pack, but there's not a lot of charge difference between 3.3v and 3.65v, so if you leave them they often settle back to 3.3v, which would be 39.6v for the pack. Most of the discharge happens between 3.3v and 3.1v. If you had a LiMnCO battery 40.3v would be too low.

Dave you are star! I checked the battery with my ebrompton and it runs fine.

I can conclude it is something wrong with my eDahon.

Thanks
Pat

 

[trex]

open the controller casing - if something smells burnt then you have a problem there. Sometimes the 2W resistor feeding the 14V regulator overheats and fails intermittently showing the symptom you described.

 

[patpatbut]

open the controller casing - if something smells burnt then you have a problem there. Sometimes the 2W resistor feeding the 14V regulator overheats and fails intermittently showing the symptom you described.

Thanks Trex. I need to open it up and check what happen to it. If something burnt I might need to replace the whole controller.

Pat