13S 48V 35A BMS with active balancing – complete protection for your Li-Ion battery pack
Building or upgrading a 48V battery pack? Don’t risk overcharged cells, short circuits, or deep discharge damage. A high-quality 13S BMS module doesn’t just protect your investment—it actively extends the lifespan of your entire battery pack. This unit balances each cell in real-time, handles 100A peak startup currents, and features a compact design that fits easily into tight enclosures.
Note: This module is exclusively for 13S Li-Ion battery configurations. Do not use with damaged cells, cells with high internal resistance, or any other series configurations.
Why choose this model? (Key Advantages):
- Active 60 mA cell balancing — Automatically activates when the voltage difference between cells exceeds 0.1V, preventing premature pack degradation.
- 100A instantaneous current — Easily handles power spikes when starting 1000W motors without triggering false protection shutdowns.
- 120A overcurrent protection — Instantly disconnects the load in milliseconds during a short circuit or overload to prevent permanent damage.
- 35A continuous discharge — Perfectly suited for 500W–1500W motors at 48V under normal operating conditions.
- Compact 69 x 51 x 8 mm footprint — Fits into almost any DIY battery casing or electric scooter housing without requiring modifications.
- Separate C- and P- ports — Independent charging and discharging paths ensure no interference between your charger and the load.
- 300 mm cable included — Practical length for direct installation without the need for extra extensions.
Performance and Specifications
The module supports a 54.6V DC charging voltage (13 cells × 4.2V), with a 35A continuous discharge current and 100A peak current—exactly what is required for electric motors during startup or sudden acceleration. The charging current is limited to 8A, making it compatible with any standard 48V Li-Ion charger.
Undervoltage protection triggers at 2.8V per cell, cutting off discharge before the cell chemistry is irreversibly damaged. The maximum allowable voltage per cell is 4.28V (±0.05V tolerance), ensuring safe charging even with less precise chargers.
| Parameter | Value / Detail |
|---|---|
| Cell Configuration | 13S (Li-Ion 18650) |
| Nominal Pack Voltage | 48V |
| Input Voltage (Charging) | 54.6V DC (13 × 4.2V) |
| Continuous Charging Current | 8A |
| Continuous Discharge Current | 35A |
| Instantaneous Discharge Current | 100A |
| Max Voltage per Cell | 4.28 ± 0.05V |
| Min Discharge Voltage per Cell | 3 ± 0.1V |
| Undervoltage Protection (Trigger) | 2.8 ± 0.08V |
| Balancing Current | 60 ± 5 mA |
| Balancing Threshold (Voltage Diff) | > 0.1V between cells |
| Short Circuit Protection | Yes (Automatic disconnect) |
| Overcurrent Protection (Trigger) | 120 ± 5A |
| Module Dimensions | 69 × 51 × 8 mm |
| Included Cable Length | 300 mm |
| Compatible Battery Type | Li-Ion 18650 |
Installation and Usage Guide
- Verify your pack configuration — this module works exclusively with 13 cells in series (13S). Any other configuration may cause permanent damage to the module.
- Connect the balancing wires (B-) to the negative terminal of the pack, then connect the individual cell wires in order, from the first to the 13th.
- Connect P- (Pack Minus) to the negative terminal of your load or output system.
- Connect C- (Charge Minus) to the negative terminal of your 54.6V charger.
- During the first charge, use a multimeter to ensure each cell voltage is between 2.8V and 4.28V.
- Automatic balancing engages during the charging process without manual intervention.
- If overcurrent or short-circuit protection triggers, remove the cause, then reconnect the power source to reset the module.
Package Contents
- 1× 13S 48V 35A BMS Module with active balancing
- 1× Connection cable (300 mm)
Frequently Asked Questions
Is it compatible with Samsung, LG, or Panasonic cells?
Yes. It works with any standard 18650 Li-Ion cell with a nominal voltage of 3.6–3.7V, regardless of the manufacturer (Samsung, LG, Panasonic, Sony/Murata, etc.). The only requirement is a 13S configuration.
Can I use this for a 500W or 1000W scooter?
Yes. A 48V 500W motor typically draws ~10–12A, while a 1000W motor draws ~20–22A continuously. With 35A continuous and 100A peak capacity, this module provides a comfortable margin for both applications, including hill climbing.
What happens if a cell drops below the limit?
The module automatically disconnects the output when any cell voltage drops below 2.8V to prevent irreversible damage. You should replace the faulty cell before putting the pack back into service.
Does it require a heatsink or active cooling?
Not for currents under 25A continuous. If you are operating near the 35A limit for extended periods, ensure passive ventilation around the module; a few millimetres of clearance is sufficient for most installations.
Does it support simultaneous charging and discharging (common port)?
No. This module features separate ports: C- for the charger and P- for the load. Connect each terminal to its designated destination—they are not interchangeable.
Photo Gallery
As**** ******ez –
Replaced the faulty BMS in my e-bike battery and it’s back to full power. Balancing is spot on.