Power Consumption by Platform Understanding your node's actual power consumption is essential for correctly sizing a solar system. The current figures below are representative community benchmarks - always measure your own node, since values vary significantly by firmware version, radio activity, transmit-power setting, and configuration. Use one consistent figure per platform across your sizing calculations. ESP32-based nodes ESP32 nodes have higher baseline power draw than nRF52 devices but offer WiFi and faster processing. As a planning figure, treat an always-on optimized ESP32 (Heltec V3) node as drawing ~40-80 mA average (higher with WiFi/MQTT active). State Factory defaults Optimized config Notes Idle (radio listening) ~150 mA ~40 mA Representative; WiFi off, screen off, BT power reduced. LoRa RX is ~40-80 mA; measure your own Active receive (packet processing) ~180 mA ~55 mA Brief peak during processing (approximate) Transmitting (high power) ~280 mA ~280 mA TX current is set by the LoRa module's PA, not the host MCU. ~280 mA is typical for a 1 W (SX126x + external PA) module; varies with supply voltage and PA design. Confirm against your module's datasheet, and verify the TX power is legal in your region Display on (OLED) +15 - 20 mA N/A (disabled) Disable for any unattended deployment WiFi active +60 - 120 mA N/A (disabled) Disable unless serving TCP bridge Key optimizations for ESP32 repeaters: Disable WiFi: largest single saving for non-TCP deployments Disable display: set screen timeout to 0 Reduce BT TX power: sufficient for app connection at short range Result: ~150 mA factory → ~40 mA optimized ≈ 3.75× improvement (illustrative; depends on your measured endpoints) nRF52840-based nodes nRF52840 devices are the preferred choice for solar and battery-only deployments due to dramatically lower power draw. As a planning figure, treat an optimized always-on nRF52840 (RAK4631, T-Echo) router/repeater as drawing ~10-15 mA average. Note that the LoRa RX/TX current is dominated by the SX126x radio, not the nRF52840 MCU. State Factory defaults Optimized config Notes Idle (radio listening) ~25 mA ~5 mA Representative; MCU sleep current plus SX126x LoRa RX (~4.6 mA boosted). Measure your own Active receive ~30 mA ~8 mA Processing packet (approximate) Transmitting (high power) ~120 mA ~120 mA TX current is set by the LoRa module's PA, not the host MCU. ~120 mA is typical for a module with an internal PA (e.g. RAK4631 ~22 dBm); a 1 W external-PA module draws far more (see ESP32 table). Confirm against your module's datasheet Deep sleep (between polls) N/A ~0.2 mA With Repeater role sleep scheduling (bare-MCU System OFF can reach ~11 µA) GPS active +25 mA N/A (disabled) Disable GPS for repeaters (typical GPS acquisition 20-40 mA) Key optimizations for nRF52 repeaters: Enable Repeater role sleep scheduling: radio polls at configurable interval between transmissions Disable GPS module (not needed for repeater operation) Disable BLE advertising when not in setup mode EasySkyMesh firmware is a power-saving fork of MeshCore (built on MeshCore v1.14.1), not Meshtastic. With its aggressive power profile (radio front-end LNA/FEM disabled) it has been measured at ~5.5 mA idle on the Heltec V4.3 (an ESP32-S3 board) while still actively listening as an always-on repeater. This is a specific firmware/config result, not a general nRF52 figure. Notable hardware benchmarks These are representative community measurements for specific boards and firmware - measure your own node before sizing a system. Device MCU Average current (repeater, optimized) Notes Heltec Mesh Node V4 ESP32-S3 ~40 mA Wi-Fi + BT disabled (representative) Heltec V4.3 ESP32-S3 ~5.5 mA idle EasySkyMesh (MeshCore-based) firmware with radio LNA/FEM off; specific config only RAK4631 WisBlock nRF52840 ~10 - 15 mA Active MeshCore/Meshtastic repeater (community-measured; measure your own) LilyGo T-Echo nRF52840 ~8 mA GPS disabled, e-ink refresh minimal (community-measured; ~3-6 mA achievable with aggressive power saving) Station G2 ESP32-S3 ~45 mA High TX power option; powered from 15 V PD (≥20 W) input Daily energy budget calculation example To size your battery correctly, work in two steps. First find the daily charge in amp-hours, then convert to watt-hours by multiplying by the pack's nominal voltage: Ah per day = (average mA × hours) / 1000 Wh per day = Ah per day × nominal voltage (V) Example: RAK4631 running optimized at ~12 mA average, 24 hours, on a 3.7 V cell: Ah per day = (12 mA × 24 h) / 1000 = 0.288 Ah/day Wh per day = 0.288 Ah × 3.7 V = ~1.07 Wh/day Battery sizing for 5-day autonomy: 0.288 Ah/day × 5 days = 1.44 Ah of usable capacity needed With 80% usable (LiFePO4 DoD): 1.44 / 0.8 = 1.8 Ah rated minimum Apply further derating for cold-weather capacity loss and end-of-life fade, plus margin for TX spikes and extra cloudy-day reserve. Practical recommendation: 5 - 10 Ah LiFePO4 gives a comfortable margin for this ultra-low-power node. For higher-draw nodes (ESP32, Pi), rerun the full derate chain (usable DoD × cold × end-of-life × margin) so the method scales correctly. Voltage and battery type reference The temperature ranges below are discharge/operating ranges. The charge range is narrower for lithium chemistries: never charge any lithium battery (including LiFePO4) below 0°C (32°F) without a low-temperature charge cutoff - sub-freezing charging causes lithium plating, permanent capacity loss, and a hidden internal-short fire risk. A solar node charges every day, so for cold climates require a BMS with low-temp protection or a charge controller with a battery temperature sensor. Chemistry Nominal voltage Discharge temp range Charge temp range Cycle life Recommended for LiFePO4 3.2V/cell −20°C to +60°C 0°C to +45°C (no charging below freezing without BMS lockout / self-heating) 2000+ cycles All outdoor deployments LiPo (LiCoO2) 3.7V/cell ~−20°C to +60°C 0°C to +45°C 300 - 500 cycles Indoor/portable only NiMH AA 1.2V/cell −20°C to +50°C 0°C to +45°C 500 - 1000 cycles Ultra-budget temporary nodes LiFePO4 is strongly recommended for permanent outdoor deployments: it handles temperature extremes (within the charge-temperature limit above) and has roughly 4× longer cycle life than LiPo. It is also much more resistant to thermal runaway than LiCoO2/NMC and rarely ignites - but it is not immune: severe overcharge, an internal short, or a puncture can still cause venting or fire. Always use a BMS and proper fusing.