# Go Kit Building for Mesh Nodes

## Introduction

A well-built mesh go kit allows rapid deployment of a fully functional LoRa mesh node in any environment - whether that is a shelter parking lot, a hilltop relay position, or the back of a command vehicle. This page covers case selection, power systems, antenna options, node hardware, and a [pre-deployment checklist](https://wiki.meshamerica.com/books/emergency-communications/page/pre-deployment-checklist).

## Case Selection

Weatherproofing is the first priority. The two most common case families are:

- **Pelican cases** (e.g., 1510 carry-on, 1450 mid-size): High-quality latches, pressure equalization valve, pick-and-pluck foam. Manufacturer-rated waterproof (Pelican rates the Protector line IP67 with the purge valve closed — check the current spec). More expensive but very durable.
- **Apache cases** (Harbor Freight): A good budget alternative that costs substantially less than Pelican. Harbor Freight markets Apache cases as IP67-rated as well (verify the current manufacturer spec). They are similar but not identical — latch durability and warranty differ. Pre-cut foam available; customizable with aftermarket inserts. Treat any price comparison as approximate and check current pricing.

For a single-node portable kit, a mid-size case (Apache 3800 or Pelican 1450) is sufficient. For a multi-node relay kit with a larger battery, the Apache 4800 or Pelican 1510 provides adequate volume.

## Power Systems

### Battery Chemistry Comparison

<table id="bkmrk-parameterlifepo4sla-"> <thead><tr><th>Parameter</th><th>LiFePO4</th><th>SLA (AGM)</th></tr></thead> <tbody> <tr><td>Energy density</td><td>Higher (lighter for same Ah)</td><td>Lower (heavy)</td></tr> <tr><td>Cycle life</td><td>2,000+ cycles</td><td>300-500 cycles</td></tr> <tr><td>Self-discharge</td><td>~3% per month</td><td>~5% per month</td></tr> <tr><td>Cold weather performance</td><td>Can discharge to about -20C, but must NOT be charged below 0C (32F) unless the pack has dedicated low-temperature charging support; a BMS usually disables charging when too cold (it blocks cold charging, it does not enable it)</td><td>Degrades below 0C</td></tr> <tr><td>Cost per Wh</td><td>Higher upfront, lower lifetime</td><td>Low upfront</td></tr> <tr><td>Recommended use</td><td>Primary portable kit</td><td>Base-station backup</td></tr> </tbody></table>

A 10 Ah, 12 V LiFePO4 battery stores 120 Wh nominal (total) capacity; at 80% depth of discharge about 96 Wh is usable. This is adequate for most single-node 12-hour deployments.

### Charge Controller

If solar charging is desired, a 10-20W solar panel is sufficient for a single-node kit. Use a charge controller that is explicitly LiFePO4-compatible (correct voltage setpoints), since LiFePO4 uses a different charge curve than SLA — the older Renogy Wanderer's lithium support varies by model and firmware, so verify before relying on it. Note that a 10A controller is far larger than a 10-20W panel needs; a small lithium-aware MPPT controller may charge more efficiently for the cost. Do not use a generic PWM controller without confirming its LiFePO4 voltage support.

## Power Budget Calculation

Before deployment, calculate the required battery capacity. Where possible, work the budget in watt-hours (Wh), not raw mAh, to avoid mixing voltage domains (a node runs at ~3.7-5 V while a "12 V" pack is at 12 V):

1. Measure or look up the current draw of the node hardware at full transmit and receive. These are approximate and depend heavily on configuration (light sleep, GPS state, screen); confirm against a meter or the Espressif/Semtech datasheets for your build. Typical ranges: 
    - T-Beam v1.1 (ESP32 + SX1276 + GPS, GPS on, no light sleep): approximately 120 mA average (idle/receive), 200 mA peak (transmit) — lower with light sleep enabled
    - RAK4631 (nRF52840 + SX1262): a few mA average with light sleep (~200 uA in deep sleep), higher in continuous receive; ~100+ mA peak during transmit. Actual average depends on sleep configuration.
2. Add loads for any accessories: OLED display ~30 mA; USB hub ~50 mA; Raspberry Pi companion ~400 mA.
3. Calculate: mAh required = total\_mA x hours divided by efficiency\_factor. Use 0.85 for a new LiFePO4 pack. To compare against a 12 V pack, convert the node load to Wh and compare to the battery's Wh rather than comparing mAh figures across different voltages.
4. Example: T-Beam (150 mA avg) + OLED (30 mA) = 180 mA x 12 h / 0.85 = **2,541 mAh minimum at the node's ~5 V rail** (roughly 13 Wh). Note that a "5 Ah 12 V" battery is about 60 Wh, so it carries well over 2x margin in energy terms — but do not read the 2,541 mAh and 5 Ah figures as a direct ratio, because they are at different voltages. Always compare in watt-hours.

## Antenna Options

<table id="bkmrk-antenna-typegainbest"> <thead><tr><th>Antenna Type</th><th>Gain</th><th>Best Use</th></tr></thead> <tbody> <tr><td>Stub/whip (stock)</td><td>2-3 dBi</td><td>Portable, handheld, omnidirectional coverage</td></tr> <tr><td>Mag-mount whip (915 MHz)</td><td>3-5 dBi</td><td>Vehicle rooftop, rapid deploy, omnidirectional</td></tr> <tr><td>Yagi (3-6 element)</td><td>8-13 dBi</td><td>Point-to-point relay link, fixed direction</td></tr> <tr><td>Fiberglass vertical (1/2 wave)</td><td>5-6 dBi</td><td>Elevated fixed relay node, omnidirectional</td></tr> </tbody></table>

**Part 15 power note:** Under 47 CFR §15.247, antenna gain above 6 dBi requires a dB-for-dB reduction in conducted transmitter power below the 1 W (30 dBm) maximum to keep EIRP within the limit. With an 8-13 dBi Yagi you must reduce transmitter output accordingly (e.g., a 13 dBi antenna requires roughly a 7 dB power reduction from 30 dBm). Pairing a 13 dBi Yagi with a full 1 W node would exceed the lawful EIRP — verify your configuration stays within the limit.

For most go kits, a 5 dBi mag-mount whip on a metal ground plane (cookie sheet, vehicle roof) provides a practical balance of gain and omnidirectional coverage. Include SMA adapters and short coax pigtails in the kit.

## Node Hardware Selection

- **LILYGO T-Beam v1.1 or v1.2**: Integrated ESP32, SX1276/SX1262, GPS, and 18650 battery holder. Best for portable handheld use. Available with 868/915/923 MHz variants.
- **RAK4631 (WisBlock)**: nRF52840 + SX1262 modular system. Excellent power efficiency, compact. Requires WisBlock Base Board. Best for compact fixed relay builds. GPS available as an add-on module.
- **Heltec LoRa32 v3**: ESP32-S3 + SX1262 + integrated OLED. Good budget option for fixed relay nodes.

## Pre-Deployment Checklist

- \[ \] Node firmware updated to latest stable Meshtastic release
- \[ \] Node name set to tactical identifier per IAP (e.g., SHELTER-B)
- \[ \] Channel/PSK configured to match operational channel plan
- \[ \] GPS fix confirmed (cold start may take 2-5 minutes outdoors)
- \[ \] Battery charged and voltage verified. Note: 12.8V is the *nominal* voltage of a 4S LiFePO4 pack, not the fully-charged figure — a fully charged 4S LiFePO4 pack rests near 13.3-13.6V (and reads ~14.2-14.6V during or just after charging). Do not treat 12.8V as 100% state of charge, or you will under-charge the pack.
- \[ \] Antenna SMA connector torqued finger-tight plus 1/8 turn (do not over-torque)
- \[ \] Coax and antenna tested for continuity (SWR check if meter available)
- \[ \] Spare 18650 cells or USB power bank included
- \[ \] [Meshtastic app](https://wiki.meshamerica.com/books/hardware-guide/page/meshtastic-app) (iOS/Android) or web client tested and connected via BLE/WiFi
- \[ \] Deployment contact list (COML name, frequency, mesh channel, check-in interval) printed and laminated
- \[ \] ICS 214 form (blank) included for activity logging
- \[ \] Case latches and pressure valve inspected; foam dry