Overview
The JKBMS BD4A17S4P is an active balance smart BMS for multi-cell battery packs, supporting Li-ion, LiFePO4 and LTO chemistries across 7S to 17S (chemistry-dependent). It is battery-pack self-powered, includes built-in Bluetooth for Android/iOS monitoring, and supports RS485 communication by default (CANBUS available as a customized interface).
Key Features
- Supported battery strings: Li-ion 7S–17S; LiFePO4 8S–17S; LTO 12S–17S
- Active balance (Full State On), balance current: 0.4A (400mA)
- Continuous charge current: 40A; continuous discharge current: 40A
- Maximum discharge current (MAX 2min): 60A
- Built-in Bluetooth; supports Android & iOS phones
- Interfaces: RS485 (default); CANBUS (customized option)
- Single cell voltage dropout detection supported
- Short circuit protection supported; temperature protection supported
- Coulomb counter supported; SoC estimation accuracy error < 8% (operating conditions)
- Smart working modes described: Storage Mode, Normal Working Mode, Shutdown, Standby Mode (set time 1–30 days)
Specifications
| Model | BD4A17S4P |
| Battery type | Li-ion / LiFePO4 / LTO |
| Number of battery strings (Li-ion) | 7S–17S |
| Number of battery strings (LiFePO4) | 8S–17S |
| Number of battery strings (LTO) | 12S–17S |
| Wiring method / output | Same port / Common Port |
| Balance method | Active Balance (Full State On) |
| Balance current | 0.4A (400mA) |
| Conductive resistance in main circuit | 2.8mΩ |
| Continuous charge current | 40A |
| Continuous discharge current | 40A |
| Maximum discharge current | 60A (MAX 2min) |
| Over charge protection current (ADJ) | 10–40A |
| Over current detect delay | 2–120S adjustable |
| Single cell voltage detection range | 0–5V, error < 10mV over full operating range; typical error < 5mV |
| Single cell voltage range (supported) | 1–5V |
| Voltage acquisition accuracy | ±5mV |
| Total voltage detection range | 0–100V, < 0.5%FSR (FSR = full scale) |
| Current sense shunt | -150A to 300A, error < 0.5%FSR |
| Over charge protection voltage | 1.2–4.35V adjustable |
| Over charge release voltage | 1.2–4.35V adjustable |
| Over discharge protection voltage | 1.2–4.35V adjustable |
| Over discharge release voltage | 1.2–4.35V adjustable |
| Temperature detection | -40 to 125°C |
| Quantity of temperature detection | 3 pcs |
| Operating temperature | -40 to 85°C |
| Storing temperature | -40 to 95°C |
| Operating power consumption | < 5mA (without communication) / 15mA (485/CAN) |
| Standby power consumption | < 2mA |
| Short circuit protection | YES |
| Temp protection | YES |
| Coulomb counter | YES |
| Bluetooth supported | iOS / Android |
| Other interfaces (default) | RS485 |
| Other interfaces (customized) | CANBUS |
| Size | 110*73*18mm |
| Power supply mode | The battery pack is self-powered |
| Battery remaining capacity accuracy | Error range is less than 8% |
| Total Cycle AH cumulative value | Half of the charge/discharge value |
Communication / Auxiliary Ports (labeling)
- CANBUS (need customization): GND / CAN_H / CAN_L
- RS485 (by default): port area labeled with GPS; pin labels shown: GND / RX / TX / VCC
- LCD (by default): K- / K+ / GND / B / A / VCC
- Heat Function (need customization): connector labeled for heating
Protection Functions (six items described)
- Over charge protection: Prevent over-charging affects battery life
- Short circuit protection: Automatic protection when short circuit protection
- Over discharge protection: Prevent the battery from running out
- Over current protection: Prevent the current from exceeding the battery range
- All-in protection: Prevent cable drop or poor contact
- Over temp protection: Prevent the battery from over heating
Applications
- Battery pack protection and active balancing for Li-ion (7S–17S), LiFePO4 (8S–17S), and LTO (12S–17S) packs
- Energy storage battery packs requiring Bluetooth monitoring and RS485/CAN communication integration
For wiring, communication interface selection, or app setup assistance, contact customer support at service@tsolar.top or visit https://tsolar.top/.
Notes
- Some promotional materials may display other JK BMS models and example app screenshots with sample values; specifications for purchase should follow the BD4A17S4P parameters listed above.
- Bluetooth usage guidance provided: download the specified Bluetooth application, activate the BMS, then select the relevant serial number to view data.
Details
Built for multi‑cell packs, the BD4A17S4P combines active balancing with Bluetooth monitoring and RS485 communication.
Wiring stays straightforward with RS485 included by default, plus expansion headers for optional interfaces depending on configuration.
Bluetooth support lets you check pack voltage, current, SOC and per‑cell data from a phone app.
Multiple working modes help reduce standby drain during storage while keeping the pack protected in normal use.
A model comparison chart helps confirm supported cell counts, current ratings and interface options before choosing a BMS.
