Q. How to fix a loose BMS Connector issue in a SUMATOTEK Lithium Battery?

A. If you are facing one or multiple of the issues mentioned below then follow the simple steps mentioned below. We strongly recommend that you keep an experienced technician by your side or get your battery checked at your point of purchase.

1. After I connect the charger to my battery, the charger FAN or Charging Indicator doesn’t turn on. To put it simply: The Battery doesn’t charge.
2. After the installation of SUMATOTEK Lithium Battery, the vehicle display turns on but when I sit on the vehicle the motor is unable to run.

Tools Required: A Multimeter, A Screw Driver, A Smartphone.

Note : In case you are unable to follow STEP 1 you can directly follow STEP 2.

STEP 1 [ Test ]: Measure the voltage of the SUMATOTEK Lithium Battery when not connected to the vehicle. Note down the reading. It should be within the range( Between the Lower Cutoff & Upper Cutoff) specified in the individual products’ technical description. Now connect the SUMATOTEK Lithium Battery to the vehicle and turn on the MCB and the key. Again measure the voltage of the battery. If the voltage reading drops to 0Volts or less than 10Volts or below the Lower Cutoff(as specified in the product’s technical description), then you need to follow the next step mentioned below.

STEP 2 [ Solution ]: The Battery Pack is managed by a BMS (Battery Management System). The BMS has multiple wires connected to a connector which is connected to each row of the battery. It is highly likely that during transportation the connector as shown in CASE A & CASE B might have gotten loose.
Under the supervision of an experienced technician open the battery and simply reconnect the connector as shown in CASE: C . Pull the connector out carefully without bending it. Bending the connector can damage the connector pins by breaking the soldering points.

Note : Always makes a full single video while opening the battery. Follow the safety instructions mentioned in a similar FAQ about how to safely open the battery in case the need arises. The video will act as proof that you have followed all the guidelines regarding opening the battery as mentioned on our website.

BMS Connector Scenario Diagram

NOTE : Always take prior written permission of authorized SUMATOTEK representative over mail/Whatsapp for opening of SUMATOTEK Lithium Batteries. In case of lack of video proof or without any written permission, you may loose your warranty.