Electric bike battery can’t charge,how to handle it?

Question 1:Ordered 1 set of 36V/12Ah electric bike battery with charger from one supplier last March.Now the li battery can’t charge.I sent several emails to this supplier,no any respond.Angry and aspire to slove it,can you help me…

Last Monday,I charged it all the whole night,but the second day,when I rode for less than 1 mile,the motor stopped.Recharged it,found the green led always on,can’t turn red.

I DON’T KNOW how to deal with it.Need help…Thanks.

Answer 1:First you need volt-meter to measure the voltage of charger and electric bike battery.Then can find problem.

Answer 2:Full charged this 36V electric bike battery reaches 42V.
1.Use voltmeter to measure the charger can get 42V.If not,charger is broken;
2.Measure battery,output voltage:33~42V,battery is also okay.If less than 33V,can’t charge it.

Answer 3:Generally the charger can’t get trouble.The problem is always from cells.
If the electric bike battery voltage is over-low.Battery’s BMS will not allow charger to work. Can’t charge for ever.
You should remove the BMS inside ev battery and let it to charge cells directly.
When voltage of the whole cells is more than standard voltage and re-connect BMS to cells.

Answer 4:Ride e-bike about one year,never meet this problem.

Question 2:The charger output 42V,but battery is 31.5V.
Disconnected cover,found a printed circuit board.But don’t know how to handle it.

Answer 5:B- → battery – (connect the cathode of the last pack of cells)
D- → – (connect to lock)
C- → – (connect to cathode of charging point)

B1 B2….B10 connects each pack of cells.

Answer 6:Your charger can’t work normal.You should disconnect 10-pin connector.
Charge it from B- and the positive of electric bike battery,bypass BMS,directly charge cells.

Note:Generally BMS can protect cells over-discharge and over-charger.But if your motor doesn’t work,just led lights work(current is less than 1A),at this time,BMS can’t protect cells.It will over-discharged your battery and make the voltage is less than normal so that can’t charger it.

We suggest if don’t ride your e-bike for more than 1 week,please remove electric bike battery power connector.