frequently asked questions

• How to confirm the type of battery?

  Check the battery body. If the normal voltage is displayed as 3.2V, the battery type is LiFePo4. If the normal voltage is 3.6V or 3.7V, it is a lithium-ion or NCM battery. You can also ask the manufacturer about the battery material.

• Is this battery management system suitable for me?

  Whether this BMS is suitable for your battery depends on two factors:

  How many battery series are in your battery pack? The purchased BMS must be the same as your battery pack.

• What is the relationship between battery capacity and BMS current?

  Battery capacity and BMS current are not directly related. Large capacity does not necessarily mean large current, and the key is sustained current. If you need higher power demand, it is recommended to choose a battery with a higher BMS current, rather than relying solely on battery capacity.

• What should I do if there is bulging or smoking after plugging in the BMS?

  It may be that the signal cable wiring is incorrect or the BMS components are damaged.

• How to solve the problem of the BMS output voltage being lower than the battery pack voltage?

  First, remove the load on the P- line of the BMS , and then unplug the BMS cable. Wait for 1 minute and then plug in the BMS cable again to measure whether there is conduction between B- and P-.

• What to do if the load or inverter is disconnected?

  1. Check whether the output voltage is lower than the battery pack voltage. If it is lower, please refer to the previous item.

  2. Discharge overcurrent protection caused by excessive load during startup.

  3. Discharge overcurrent protection caused by large capacitors in the controller.

• What should I do if the signal cable heats up after being plugged in?

  Check whether the signal cable is short-circuited. If so, you need to replace the signal cable. Do not plug in the BMS.

• Why do the red and green lights on the charger alternate flashing during charging?

  This problem is affected by many factors, such as charger type matching and battery consistency. If you encounter this problem, please contact the salesperson, they will help you find a solution.

• After using for a period of time, there is a large voltage difference between each string of batteries?

  1. Use batteries with better consistency from the same batch to reduce voltage difference.

  2. The BMS is like an intelligent switch on the negative wire, and it will not discharge individual batteries in the group separately within the equilibrium value.

• What should I do if the battery is not charged due to long- term storage and under-voltage?

  Remove the BMS, charge it to a normal level, and then insert the BMS for charging.

• Why is the battery usage time shorter than before?

  When the battery is discharged, you can measure the voltage of each battery string. One of the battery strings may have a voltage significantly lower than the other battery strings.

• What should I do if the power is cut off during acceleration or uphill?

  The current of the BMS is too small, which triggers the discharge overcurrent protection. You need to replace a larger current BMS.

• What are parallel and separate ports? What is the difference?

  In this case, we take the 13S 48V16A BMS as an example:

  Parallel port refers to connecting your charging negative pole and discharge negative pole to the same end point (our P-). Therefore, the charging current and discharge current are both 16A.

  Separate port refers to connecting your charging negative pole to our C- and discharge negative pole to our P-. Therefore, the charging current and discharge current are different. The discharge current is 16A, and the charging current is 8A.

• Is there a minimum order requirement?

  No. We provide various capacities and sizes for different customers and welcome ODM/OEM. We are happy to provide services according to your requirements.

• What payment methods do you use?

  We accept multiple payment methods, such as PayPal, T/T, L/C, etc. Welcome to discuss with us.

• What is a BMS?

  A battery management system (BMS) is an intelligent management system that manages and maintains each battery unit, prevents overcharging and overdischarging of batteries, extends battery life, and monitors battery status.

• Do I need a BMS?

  It is recommended to use a BMS because it has many benefits. First, it ensures safety by preventing overcharging and protecting against fires. Additionally, it makes charging easier.

• What are the main functions of the SMART BMS application software?

  Battery status monitoring: Real-time monitoring of the voltage, current, temperature, and other status information of the battery pack.

  Battery performance analysis: Analysis and prediction of the SOC, SOH, remaining capacity, and other parameters of the battery pack.

  Safety control: Monitoring of the status information of the SMART BMS system, and immediate action can be taken in case of abnormal situations.

  Data recording and report generation: Recording of the historical status information of the battery pack, and generation of various charts and reports for analysis and evaluation by the user.

  Communication function: Real-time communication with the SMART BMS system through the communication interface.

• What is a BMS?

  An excellent PCM or PCB (Protection Circuit Module or Board) is like the "brain" of a lithium-ion battery pack. Its role is to protect the lithium-ion battery pack from overcharging, over-discharging, and overuse, to obtain better backup and healthy battery life. In addition, it can also protect the battery pack from explosions, fires, and damage.

• How does the BMS work?

  The BMS contains an electronic circuit that can accurately monitor the voltage and current of the battery and the charging/discharging circuit in an environment of -40°C to +85°C, and timely control the on/off state of the current circuit. In addition, the BMS can prevent battery damage in high-temperature environments.

• What is a lithium BMS? What is the principle of the BMS?

  The reason why lithium batteries (rechargeable) need to be protected is because of their own characteristics. The material of lithium batteries determines that they cannot be overcharged, over-discharged, overcurrent, short-circuited, and withstand ultra-high temperature charging and discharging. Therefore, lithium battery components will always carry a BMS.

• What electronic components are usually included in a lithium BMS?

  Common lithium BMS usually include control ICs, MOS switches, resistors, capacitors, and auxiliary devices such as FUSE, PTC, NTC, ID, memory, etc. The control IC controls the MOS switch to conduct in all normal conditions, making the battery and the external circuit conductive. When the battery voltage or circuit current exceeds the specified value, it immediately controls the MOS switch to conduct and disconnect to protect the safety of the battery.

• Why can't you charge after discharging protection?

  Some styles of BMS need to be charged and activated after discharging protection in order to have output. Your charger may have a function to detect voltage, and it will not charge if it does not detect output. If the charger has a voltage detection function, it is best not to use over-discharge protection.

• Why is there no overcharge protection?

  The protection voltage of iron-lithium batteries is 3.75V, and the protection voltage of NCM batteries is 4.25V. Only when the entire battery pack reaches this protection voltage, will it be fully protected. If it does not reach this voltage, it will not be protected. If the battery reaches the protection voltage, but there is no protection for more than 0.03V above this parameter, you need to check whether the wiring is correct, whether the charging negative is connected to the corresponding position according to the wiring diagram, and whether the matching charger is used. If all checks are normal, it may be that the charging MOS of the BMS is broken and needs to be sent back to the manufacturer for testing.

• Why are only one or two lights on when fully charged? Why is the BMS unbalanced?

  The BMS will start to discharge when one of the batteries reaches 4.18V (NCM) or 3.6V (iron-lithium). This means that some batteries are also discharging while charging, while others are only charging. When the highest battery reaches 4.25V (NCM) or 3.75V (iron-lithium), the BMS will stop charging to protect the battery. The series battery pack is charged and discharged in the same way, so if your battery consistency is not good enough, the BMS may not achieve the best balance effect. Balance is mainly to extend the battery life and make the battery consistency better, but the battery consistency cannot rely entirely on the balance function, which still depends on the battery difference of the PACK to determine.

• Wiring Tips

  The wiring sequence is as follows: first solder the B- thick wire (recommended length within 15cm), the shorter and thicker the better; then connect the signal cable. Do not insert the signal cable into the BMS while it is connected to the battery. First connect each signal cable in order, then plug it into the BMS. Finally, solder the charging negative and load negative. Confirm that the total battery voltage is equal to the BMS output voltage before using it for charging and discharging.

• Why does the BMS trigger protection after being charged, and why does it shut down when climbing hills?

  This is generally due to battery problems. You can use a multimeter to measure the voltage drop of each battery cell while discharging. Cells with lower capacity charge and discharge faster, and consume more power when climbing hills, leading to a faster voltage drop. Many buyers have reported that their battery works fine without the BMS. This is because the BMS is not there to protect the battery. You can replace the battery with better consistency.

• Why can't I charge the battery after wiring it, but I can discharge it?

  You can use a multimeter to measure the voltage of each battery cell to see if the battery voltage has reached the maximum value, which triggers the overcharge protection of the BMS. In this case, you can discharge the battery for a period of time until the voltage drops, and then use it for charging.

• Why isn't the balancing function of the BMS enabled?

  Please check whether you have set the static balance or charging balance. Charging balance: the balancing function is only enabled when there is charging current, and the battery reaches the set balancing voltage, and the highest and lowest strings reach the set voltage difference; static balance: the balancing function is enabled when there is no charging current, and the battery reaches the set balancing voltage, and the highest and lowest strings reach the set voltage difference.

• Why does the BMS only balance one side of the battery cells?

  The BMS enables odd and even battery cell balancing alternately to reduce heat generation.

• Why is the voltage of the first and second cells 0.xV, but the measured voltage is normal?

  Usually, this is caused by poor connection of the B- thick wire. Please check whether your BMS has soldered the B- thick wire to the total negative of the battery. Long and thin wires are prone to burn the BMS

• Why does one cell have no voltage, while the adjacent cells are higher? The measured voltage is normal.

  One possible situation is poor connectivity. Please check the battery pack connection and fix any loose connections on the cell with no voltage and its adjacent cells. It may also be caused by the balancer being damaged, in which case the BMS needs to be sent back to the manufacturer for repair.