# T-Beam Build Guide (TTGO/LilyGO)

## Overview

The TTGO/LilyGO T-Beam is one of the most popular all-in-one LoRa mesh boards available. A single PCB integrates an **ESP32 microcontroller**, an **SX1262 LoRa radio**, a **GPS module**, and an **18650 Li-ion cell holder** with onboard charging - making it an excellent starting point for a portable or fixed mesh node.

## Versions & Variants

- **T-Beam v1.1** - The most common variant. Uses the SX1262 radio and the AXP192 power management IC. Available in 868 MHz (EU) and 915 MHz (US/AU) versions.
- **T-Beam Supreme** - Upgraded to ESP32-S3 and SX1268 radio. More processing power and improved RF performance. Uses AXP2101 PMIC.
- **T-Beam M8N vs M10 GPS** - Refers to the GPS module fitted. The M10 (ublox M10) acquires faster and has better cold-start performance. Check the board revision markings or product listing to confirm which GPS module your unit has.

## Bill of Materials

- T-Beam board (select your frequency band: 868 or 915 MHz)
- 18650 Li-ion cell, 2500 mAh or greater (e.g. Samsung 25R, LG MH1, Panasonic NCR18650B)
- SMA antenna matched to your frequency band
- USB-C or Micro-USB cable (varies by board version) for flashing and charging
- Optional: IP67 waterproof enclosure (Hammond 1554 series or equivalent), cable gland for SMA pigtail

## [Flashing Meshtastic Firmware](https://wiki.meshamerica.com/books/diy-build-guides/page/flashing-meshtastic-firmware)

1. Open **Chrome or Edge** (Web Serial API is required - Firefox is not supported).
2. Navigate to [flasher.meshtastic.org](https://flasher.meshtastic.org).
3. Connect the T-Beam to your computer via USB.
4. In the flasher, select the device family: **TTGO T-Beam**. Choose the correct sub-variant (v1.1, Supreme, etc.) if prompted.
5. Click **Flash**. The flasher will erase and write firmware automatically. Do not disconnect during the process.
6. Once flashing completes, the device will reboot. Use the [Meshtastic app](https://wiki.meshamerica.com/books/hardware-guide/page/meshtastic-app) (Android/iOS) or the web client at [client.meshtastic.org](https://client.meshtastic.org) to complete initial configuration (region, node name, channel).

## [Flashing MeshCore Firmware](https://wiki.meshamerica.com/books/diy-build-guides/page/flashing-meshcore-firmware)

1. Navigate to [flasher.meshcore.io](https://flasher.meshcore.io) in Chrome or Edge.
2. Connect the T-Beam via USB.
3. Select **T-Beam** from the device list, then choose the firmware role - typically **Repeater** for a fixed infrastructure node.
4. Click **Flash** and wait for completion.
5. Configure the node using the MeshCore companion app or serial console.

## Critical Gotcha: Power Management IC Mismatch

The T-Beam uses a Power Management IC (PMIC) to control battery charging and power rails. The T-Beam v1.1 uses the **AXP192**, while the T-Beam Supreme uses the **AXP2101**. Firmware must include drivers for the correct PMIC.

**If you flash the wrong firmware variant, the board will appear to work but the battery will not charge.** Always confirm your board hardware revision before selecting firmware. The revision is usually silkscreened on the PCB (look for "V1.1", "SUPREME", etc.). Both Meshtastic and MeshCore flashers list variants - match the label carefully.

## Outdoor Deployment Tips

- Use an **IP67-rated enclosure** - Hammond 1554 series polycarbonate boxes are widely used and available in sizes that fit the T-Beam comfortably. Bud Industries and Fibox TEMPO are good alternatives.
- Drill a hole for an SMA bulkhead connector or a waterproof SMA pigtail using a cable gland rated IP68. The antenna should mount outside the enclosure.
- Add a silica gel desiccant pack inside the enclosure to absorb moisture. Replace annually. Consider a Gore-Tex breather vent to equalise pressure without admitting moisture.
- Avoid mounting in direct sun if possible - internal temperatures can exceed 70°C in sealed plastic enclosures in summer. Use a UV-resistant box and shade the enclosure where feasible.

## Power Notes: Extended Battery Capacity

The T-Beam's onboard 18650 holder limits you to a single cell (~3,000 - 3,500 mAh maximum with a high-capacity cell). For permanent fixed installations requiring multi-day autonomy or solar charging:

- The T-Beam exposes battery pads (B+ and B-) accessible on the PCB.
- You can connect an external **LiFePO4** battery pack via these pads, but you **must bypass the onboard charging circuit** and use a dedicated LiFePO4 charge controller, as the onboard charger is configured for Li-ion voltage curves and will overcharge a LiFePO4 cell.
- An alternative is to power the board through the 5V input pin with a regulated supply from a solar charge controller, bypassing battery charging entirely.
- For simpler builds, a large-capacity Li-ion power bank with pass-through charging can be used to power the USB input.