LTO 2.4 V / 3900 mAh battery pack with battery management system
This 1S3P Lithium Titanate (LTO) battery pack is designed for low-power outdoor applications such as LoRa nodes, IoT, HAM radio setups, and DIY electronics. It features an integrated smart Battery Management System (BMS) with voltage, current, and energy measurement, along with protection features including under-voltage lockout (UVLO), over-voltage lockout (OVLO), and overcurrent protection (OC). The battery pack communicates via I²C, allowing real-time monitoring of power parameters.
I developed this battery pack and BMS specifically for use with my Meshtastic Motherboard and solar-powered Meshtastic station.
This project is partially open-source, with public schematics, a 3D model in STEP format, a 3D-printable enclosure, and firmware.
Features
- Battery Chemistry: Lithium Titanate (LTO) for extended lifespan and extreme temperature resilience
- Configuration: 1S3P (three LTO 18650 cells in parallel)
- Nominal Voltage: 2.4 V
- Voltage Range: 1.5 – 2.8 V
- Capacity: 3.9 Ah (1300 mAh per cell)
- More details in the datasheet
- BMS Features:
- Overvoltage and undervoltage protection
- Overcurrent protection
- I²C communication for real-time battery monitoring (voltage, current, power)
- User-upgradable firmware (UPDI programming interface)
- Overvoltage and undervoltage protection
- Fully open-source firmware, available on GitHub under the MIT license
Applications
- LoRa devices like Meshtastic, MeshCore, or Reticulum
- IoT and battery-powered sensors
- HAM radio setups
- DIY outdoor and low-power electronics
Why BMS for 1S LTO?
My motivation for designing this battery pack with a BMS came mainly from working on the Meshtastic project. Nodes powered by batteries and charged via solar panels are typically placed outdoors, and I wanted them to be rechargeable even in winter when temperatures are below zero degrees C and the sun shines only briefly. Originally, I was using 1S Li-Pol batteries, but with winter around the corner, it was time to look for alternatives.
With no good and ready-to-use product available, I decided to design my own BMS with protection features. It took me almost half a year of experimenting and prototyping. Winter came and went, and at the beginning of spring 2025, I had the first production series of this battery pack.
Here were my requirements for the BMS:
- Protection specifically for 1S LTO batteries. I already had a Meshtastic board prepared for them, and no such protection existed (all BMS solutions I found were for 4S LTO and larger packs), so it made sense to develop my own.
- Support for low discharge currents in the tens to hundreds of mA
- Charging currents up to 1 A (or the maximum output of the solar panel)
- Protection against under-voltage (UVLO), over-voltage (OVLO), and overcurrent (OC)
- Bonus features like configurability and real-time measurement were nice to have but not essential
The result of this development is the product you see here.
Package Includes
- Fully assembled battery pack with three 1300 mAh LTO cells in parallel, BMS PCB, and 3D-printed enclosure
- 100 mm long data cable with JST-SH-1.0 mm connectors on both ends for easy connection to the Meshtastic Motherboard
Why Buy from Me?
I’m a maker, Meshtastic, and HAM radio enthusiast who designs and manufactures every board myself. Sharing my creations with other makers is my way of contributing to the community I love. By purchasing from me, you not only support my work but also help fuel future designs and innovations. Your support means the world — thank you!
Links to code and documentation
Shipping policy
I use Packeta for shipping, a Czech company that delivers packages using the best method for each destination country.
Shipping Times: Typically under 2 weeks for the European Union and some other European countries.
Lost or Damaged Packages: If your package is lost or damaged during transit, please contact me. I’ll work with you to find the best solution.
Shipping to Other Countries: If your country isn’t listed (outside the EU), feel free to send me a message. I’ll do my best to find a way to ship the package to you.
If you have any questions or if something went wrong, send me a message, and I'll do my best to resolve the issue.
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