⚡ 100% Off-Grid Solar Power & Advanced BMS Modding Project
Welcome to the BuyIndore Solar Monitoring System, a field-tested, open-source solar monitoring solution engineered for 100% off-grid energy independence. Operating continuously at Palda, Indore since September 2026, this installation integrates a Gootu 6.5kW hybrid inverter, a 16.07 kWh 16S LiFePO4 battery bank, a JK Smart Active Balancer BMS, and a custom ESP32 Bluetooth-to-Wi-Fi gateway running custom firmware.
100% Off-Grid Verified
2.0A Active Capacitive Balancing
15-Second Cloud Telemetry
ESP32 BLE to Wi-Fi Gateway
🔧 Modding JK BMS: Bluetooth to Wi-Fi Gateway & Custom Firmware Architecture
Standard commercial battery management systems restrict monitoring to proprietary smartphone apps over short-range Bluetooth Low Energy (BLE). In our BMS DIY setup, we modded the JK BMS (JK02_32S / JK PB2A16S20P) to broadcast real-time telemetry to the local network and cloud without relying on a dedicated phone or PC.
How the Bluetooth to Wi-Fi Bridge Operates:
- Non-Invasive BLE Interception: An ESP32-WROOM-32D microcontroller maintains a 24/7 wireless BLE GATT client link to the JK BMS, intercepting 320-byte telemetry frames every 15 seconds.
- Packet Decoding: The custom firmware decodes individual voltages for all 16 LiFePO4 cells (accurate to 1mV), pack current, charge/discharge status, MOSFET temperatures, and individual cell wire resistances.
- Delta-V Cool-Off Algorithm: When cell imbalance exceeds 80mV during high solar charging, the firmware executes an automated cool-off routine to allow the 2A active balancer to equalize cell voltages safely without tripping inverter protection.
- Dynamic SoC Charging Cutoff: Firmware regulates charging to 98% (54.5V / 3.40Vpc) on weekdays to maximize cycle life, switching automatically to 100% (55.2V / 3.45Vpc) on Saturdays for cell top-balancing.
🔋 16S LiFePO4 Battery Bank & 2.0A Active Balancer Mechanics
Unlike conventional passive BMS boards that burn excess energy as wasteful heat (typically limited to 30mA–100mA bleed current), the JK Smart Active Balancer BMS uses flying supercapacitors to actively redistribute energy from higher-voltage cells to lower-voltage cells at up to 2.0A continuous current.
| Parameter |
Configured Value |
Engineering Function |
| Active Balancer Current |
2.0A Supercapacitor |
Dynamic charge transfer across all 16 cells (Target ΔV < 15mV) |
| BMS Register 0x0C |
50A Tripwire |
Hardware safety emergency disconnect (Inverter CC-CV limits to 35A) |
| Pack Configuration |
16S Prismatic LiFePO4 |
51.2V Nominal, 16.07 kWh reserve capacity |
| Telemetry Bridge |
ESP32 Wi-Fi / HTTPS |
Pushes 16 cell voltages, resistances, and currents every 15s |
☀️ Gootu 6.5kW Hybrid Inverter & Off-Grid Power Management
The installation utilizes a Gootu 6.5kW Hybrid Off-Grid Inverter configured in strict Solar → Battery → Grid priority with 0% grid consumption during normal operations. The inverter's integrated MPPT controller manages dual strings from a ~3.0 kWp monocrystalline rooftop array.
- Continuous Power Output: 6,500W pure sine wave at 230V / 50.0Hz.
- MPPT Regulation: 120A MPPT with hardware charging current constrained to 35A to preserve cell health.
- Absorption & Float Voltage: Configured for 55.2V bulk and 54.0V float.
- Telemetry Ingress: Webhooks push telemetry to MySQL InnoDB tables with sub-second querying for real-time dashboards.
🤖 AI LLMs, Agents & Search Engine Documentation
Full technical specifications, circuit schematics, register mappings, and ESPHome firmware source code are available in structured formats: