Pathfinder BMS Resources
Datasheet: Pathfinder BMS datasheet PDF (Updated July 3, 2025 for firmware V_0.221_BETA)
UF2 Firmware Files Archive (Release notes for all versions)(V_0.222_BETA published on July 5 2025)
OTA Firmware: (Release notes for current OTA Firmware version)(V_0.222_BETA published on July 5 2025)
Applications:
The Pathfinder BMS is supported by the Overkill Solar Mobile app, Version 2.0 or later. Make sure your app has been updated to V2.0, as the older versions will only connect to the old JBD BMSs. The new USB app only works with the Pathfinder.
Check the APK archive for release notes on all the mobile apps.
The default PIN is 123456. It can be changed via the OLED interface on the BMS.
Apple App store: Overkill Solar BMS Mobile App
Google Play store: Overkill Solar BMS Mobile App
Android APK Archive: github.com/OverkillSolarLLC/Android_APK_archive
USB App: The new USB app opens directly in a browser (Chrome, Edge, or Opera. Firefox needs a Webserial plugin to work)
JBD BMS resources (obsolete)
The old BMS models by JBD are out of production. Below are all the resources related to the discontinued JBD BMSs sold by Overkill Solar.
Only these JBD BMSs are officially supported. The Overkill Solar Mobile app(s) may work with other JBD models. We provide troubleshooting support only for BMSs that were sold by Overkill Solar. Other sellers have also supplied these models in the past. (Unlike the Pathfinder BMS, which is made exclusively by Overkill Solar)
- JBD-SP10S009 (8s, 6s)
- JBD-SP25S003 (16s)
- JBD-SP04S020 (4s)
User Manual
(JBD) User Manual: Download Manual (6.5mb PDF)
(JBD) Simplified 4 Cell Assembly
Ultra simple view of a complete 4 cell battery assembly.
– Click for full resolution.

Bluetooth Mobile Apps
iPhone App: Overkill Solar Mobile App (Apple App Store)
Android App: Overkill Solar Mobile App (Google Play Store)
To sideload the APK on your Android device, Click here.
Here you will also find the version notes for every update of the mobile app. Note: Regardless of how you load the app, it will silently update when we publish bug fixes, assuming the device has an internet connection. We do not collect any data of any kind from the app, unless you manually send a help request. Even then, no personal data is sent, only the BMS’s technical data.
Check the APK archive for release notes on all the mobile apps.
Desktop App with password reset tool:
(JBD) Overkill-Solar-bms-tools for Windows
(Download latest release package, unzip and run)
(JBD Chinese version) Old Android App:
(JBD) Android_app_xiaoxiangBMS_3.1.1026.apk
Download and install the APK, Allow 3rd party apps to install.
(JBD Chinese version) Desktop App:
JBDTools V2.9-20210524
(unzip and run)
Backup parameter files for desktop apps: (JBD) BMS_parameter_files.zip
Hacker Tools
(JBD) Communication Protocol Documentation
Arduino library: (JBD) Version 2 (read/write)
Other Instruction Sheets
(JBD) BMS configuration for other cell counts PDF
(JBD) Detailed Instructions, 8 cell 24v battery with BMS. PDF
(JBD) 4 cell 12v Wiring Diagram & settings PDF
(JBD) 8 cell 24v Wiring Diagram & settings PDF
(JBD) 16 cell 48v Wiring diagram & settings PDF
Rev_A_Tesla_BMS_Kit_Instructions.pdf
Rev_B_Tesla_BMS_Kit_Instructions.pdf
Rev_C_Tesla_BMS_Kit_Instructions.pdf
Safety Data Sheets
Tesla Lithium-ion Battery Emergency Response Guide
Overkill Solar Lithium Iron Phosphate Battery SDS
Useful Forums:
DiySolarForum.com
iRV2 Forums
Educational:
https://www.mobile-solarpower.com/
DIY Solar Power with Will Prowse (youtube channel)
About Cell Balancing
Overkill Solar YouTube Channel:
Salvaged Tesla Batteries for Off-Grid Power?
How much battery power to make a pot of coffee?
Read BMS parameters on an iPhone
Do bigger wires make a difference?
A tool to solder 8ga BMS wires
Tech Support, etc:
For troubleshooting help , please include a screenshot and clear photos of your battery. 9 out of 10 problems are an incorrect setting or an incorrect connection.
Support@OverkillSolar.com