DALY - Active SMART Balancer 4S

Intelligent management of energy transfer between battery cells and protection against premature damage. The Daly balancer communicates via UART, RS485, or Bluetooth. Use it to enhance the performance and stability of the cells. Suitable for lithium batteries LiFePO4. To communicate via Bluetooth, download the SMART BMS app for Android, or the SMART BMS app from the Apple Store, or PC software.

You can also use the QR code to download the app.


Balancing current: 0~1A. Suitable for 3-24s LiFePO4 batteries. Compatible with other BMS brands. The DALY active balancer is applied in energy storage systems using lithium batteries, such as e-bikes, electromobility, outdoor and indoor energy storage.

Technical Specifications:

  • ◾ Package includes: active SMART balancer 4S with cables for connecting individual cells
  • ◾ Suitable for battery types: LiFePO4
  • ◾ Number of connected batteries in series: 4
  • ◾ Balancing current: 0.5~1A
  • ◾ Balancing mode: active balance
  • ◾ Standby current consumption (no load): 300uA
  • ◾ Operating temperature range: -20℃ to 60℃
  • ◾ Communication: UART/RS485/Bluetooth
  • ◾ Indicator: On/Off/Error LED

Optional Accessories for SMART BMS and DALY Balancers

Bluetooth Module

Used for connecting to a Bluetooth app on external software (tablet, mobile). Length: 45cm.


Fast response and stable performance over a long period. With NTC, you can monitor the battery temperature through the app. Length: 25cm.

Communication Cable

Wire harness with lugs for easy connection and prevention of disconnection. Length 30cm (3~6s), 35cm (7s), 45cm (8~24s, ≤100A), 60cm (3~24s, ≥120A).

daly bms and balancer

Manufacturer's instructions for DALY smart BMS and balancers

Sequence of connecting BMS to the battery:
Make sure to use appropriate twisted wires with correct cross-section; B- and P- should have different colors. Pay attention to the markings of the B and P poles.

  1. During the installation of wires, they must not be connected to the BMS. The battery must be composed of cells arranged in series.
  2. The wiring starts with a thin black wire connecting the main negative pole of the battery (B-) and the second wire (red) is connected to the positive pole of the first cell, followed by the second pole of the second cell, to which the second red wire is connected.... until the last positive pole of the last cell in the battery chain, which is also the main positive pole of the battery (B+).
  3. After completing the wiring of the cell poles, measure the voltage between two adjacent metal terminals of individual cells. The voltage of LiFePO4 cell should be between 2.5~3.6V. Before proceeding, make sure the voltage is within the recommended ranges.
  4. Connect the B- wire (blue) to the main negative pole of the battery (the length of the B- wire should not exceed 40 cm).
  5. Only then insert the connector with the cables into the BMS busbar.

After completing the wiring:

  1. Measure the voltage of the battery between the B+ and B- terminals, and the voltage between the B+ and P- terminals. The voltages should be the same. This represents the voltage of the battery itself, including the BMS. Matching voltages indicate that the BMS is functioning correctly. If not, recheck the order and system of the connections.
  2. The positive charging and discharging terminals are directly connected to the overall positive terminal (B+) of the battery. The method of connecting the common port of the BMS involves connecting the negative charging and discharging terminals to the P- terminal. The negative charging terminal is connected to C-, and the negative discharging terminal is connected to P-.

Connection of the active balancer

※ The active balancer must match the BMS with the same string count/number (S). Different S numbers cannot be combined.

  1. After completing the BMS installation, check the correct connection of all wires;
  2. The cable plug (connector) corresponds to the BMS connector and the active balancer connector (bus). The BMS connector and the active balancer connector (bus) can be swapped. Before starting the BMS, ensure that the active balancer is correctly connected, and the BMS is securely installed and connected to the battery. Otherwise, the BMS may function incorrectly or may cause permanent damage to the equipment due to a short circuit.

daly bms and balancer


DALY Smart Active Balancer [cs]

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