Power Consumption Reference

Power Consumption by Platform
Understanding your node's actual power consumption is essential for correctly sizing a solar system. These measurements are from community benchmarks - values vary by firmware version, radio activity, and configuration. 

 ESP32-based nodes 
 ESP32 nodes have higher baseline power draw than nRF52 devices but offer WiFi and faster processing. 

 
 
 State Factory defaults Optimized config Notes 
 
 
 Idle (radio listening) ~150 mA ~40 mA WiFi off, screen off, BT power reduced 
 Active receive (packet processing) ~180 mA ~55 mA Brief peak during processing 
 Transmitting @ 27 dBm ~280 mA ~280 mA TX power draw is fixed by hardware 
 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 
 

 nRF52840-based nodes 
 nRF52840 devices are the preferred choice for solar and battery-only deployments due to dramatically lower power draw. 

 
 
 State Factory defaults Optimized config Notes 
 
 
 Idle (radio listening) ~25 mA ~5 mA With deep-sleep radio polling 
 Active receive ~30 mA ~8 mA Processing packet 
 Transmitting @ 27 dBm ~120 mA ~120 mA TX power draw is fixed 
 Deep sleep (between polls) N/A ~0.2 mA With Repeater role sleep scheduling 
 GPS active +25 mA N/A (disabled) Disable GPS for repeaters 
 
 

 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 (community fork): achieves ~5.5 mA average on Heltec V4.3 - the lowest known idle current for a Heltec device 
 

 Notable hardware benchmarks 

 
 
 Device MCU Average current (repeater, optimized) Notes 
 
 
 Heltec Mesh Node V4 ESP32-S3 ~40 mA Wi-Fi + BT disabled 
 Heltec Mesh Node V4.3 ESP32-S3 ~5.5 mA EasySkyMesh firmware only 
 Heltec T096 nRF52840 ~12 µA Deep sleep; new as of April 2026 
 RAK4631 WisBlock nRF52840 ~5 - 8 mA Standard MeshCore repeater firmware 
 LilyGo T-Echo nRF52840 ~8 mA GPS disabled, e-ink refresh minimal 
 Station G2 ESP32-S3 ~45 mA High TX power option; requires 15V PD power 
 
 

 Daily energy budget calculation example 
 To size your battery correctly: Wh per day = (mA × hours) / 1000 
 Example: RAK4631 running optimized at 6 mA average, 24 hours: 
 Energy per day = (6 mA × 24 h) / 1000 = 0.144 Ah/day = ~0.53 Wh/day @ 3.7V

Battery sizing for 5-day autonomy:
 0.144 Ah/day × 5 days = 0.72 Ah minimum
 With 80% depth-of-discharge: 0.72 / 0.8 = 0.9 Ah LiFePO4 minimum
 Practical recommendation: 5 - 10 Ah LiFePO4 for comfortable 5-day margin plus TX spikes
 

 Voltage and battery type reference 
 
 Chemistry Nominal voltage Temp range Cycle life Recommended for 
 
 LiFePO4 3.2V/cell −20°C to +60°C 2000+ cycles All outdoor deployments 
 LiPo (LiCoO2) 3.7V/cell 0°C to +45°C 300 - 500 cycles Indoor/portable only 
 NiMH AA 1.2V/cell −20°C to +50°C 500 - 1000 cycles Ultra-budget temporary nodes 
 
 
 LiFePO4 is strongly recommended for permanent outdoor deployments: it handles temperature extremes, has 4× longer cycle life than LiPo, and will not catch fire if overcharged or punctured.

Solar Sizing Guide
A correctly sized solar system keeps your repeater running indefinitely with no maintenance - an undersized system fails within days during cloudy weather. 

 The two goals of solar sizing 
 
 Enough panel to fully recharge the battery on a typical sunny day 
 Enough battery to run through several consecutive cloudy days (autonomy period) 
 

 Step 1: Calculate daily energy consumption 
 Use the power consumption tables on the previous page. For a typical optimized nRF52 repeater (6 mA average): 
 Daily consumption = 6 mA × 24 h = 144 mAh = 0.144 Ah
At 3.7V: 0.144 Ah × 3.7 V = 0.53 Wh/day 
 For an ESP32 repeater at 40 mA: 40 × 24 = 960 mAh = 3.55 Wh/day 

 Step 2: Size the battery 
 Rule of thumb: target 5 days of autonomy (no sun). Use 80% usable depth-of-discharge for LiFePO4: 
 Battery (Ah) = (daily consumption × 5 days) / 0.8

nRF52 example: (0.144 Ah × 5) / 0.8 = 0.9 Ah minimum → use 5 - 10 Ah for margin
ESP32 example: (0.96 Ah × 5) / 0.8 = 6.0 Ah minimum → use 10 - 20 Ah
 

 Step 3: Size the solar panel 
 Assume 4 peak sun hours per day (conservative for most of North America year-round). Add 25% for charge controller inefficiency and panel degradation: 
 Panel (W) = (daily Wh × 1.25) / peak sun hours

nRF52 example: (0.53 Wh × 1.25) / 4 = 0.17W minimum → 1 - 3W panel is more than sufficient
ESP32 example: (3.55 Wh × 1.25) / 4 = 1.1W minimum → 5 - 10W panel recommended 

 Typical RegionMesh community build: $180 - $300 
 This is the build specification widely used by community mesh networks including RegionMesh and CascadiaMesh : 

 
 Component Spec Cost 
 
 Solar panel 5W, south-facing, 30 - 40° tilt (match your latitude) $15 - 25 
 Charge controller 5A MPPT (e.g. Victron 75/5 or generic CN3791) $15 - 30 
 Battery LiFePO4 10 Ah (4S, 12.8V) or 3.2V single cell 10 Ah $25 - 60 
 Radio board RAK4631 or Heltec V4 or T-Echo $18 - 75 
 Enclosure IP65 ABS junction box, 200×120×75mm $10 - 20 
 Antenna 5 dBi fiberglass, N-female mount $15 - 25 
 Misc Cable glands, silicone, fuse, wiring $10 - 20 
 Total $108 - $255 
 
 

 Panel mounting orientation 
 
 Azimuth: Face south (in North America). A deviation of up to 30° east or west reduces output by only ~5%. 
 Tilt angle: Set to your latitude for best year-round average. Steeper tilt (latitude + 15°) optimizes for winter; shallower (latitude − 15°) for summer. 
 Avoid shading: Even partial shading of one cell can reduce output of the entire panel significantly. Use terrain and shadow analysis before finalizing mount position. 
 

 Charge controller: MPPT vs PWM 
 Always use MPPT for solar-powered mesh nodes: 
 
 MPPT controllers extract up to 30% more power from the panel under real-world conditions 
 On small systems (3 - 10W panels), this can be the difference between running indefinitely and failing in winter 
 PWM is only acceptable for large panels where the extra efficiency isn't needed to meet the load

Power Consumption Measurement Methods
Accurate power consumption measurements help you design realistic solar power systems and understand why your battery life differs from specifications. This page covers practical measurement techniques for mesh node operators. 

 Measurement Tools 
 
 USB power meter (basic): Plugs between USB charger and device. Shows voltage, current, and power in real time. Cost: $5-15. Limitation: only measures USB-powered devices; can't measure 3.3V or 3.7V native power. 
 USB power meter (logging): Same as above but logs data over time. Shows how consumption varies between sleep/wake/transmit cycles. Cost: $15-30. Good for average consumption calculations. 
 Multimeter in current mode: In-series measurement with any power supply. More flexible; requires cutting a wire in the power path. Risk: damage from wrong meter range selection. 
 Current probe/clamp meter: Non-invasive; clamps around a wire to measure current. AC current only in basic versions; specialized DC clamp meters cost $40-100 but don't require circuit modification. 
 Nordic PPK2 (Power Profiler Kit 2): $80 professional-grade tool from Nordic Semiconductor. Measures nRF52 current with microsecond resolution. Perfect for profiling sleep vs. active states. Shows detailed consumption waveform. 
 

 Measuring Average vs. Peak Current 
 A critical distinction: 
 
 Peak current (transmit): 80-120 mA for 100-300 ms during transmission. Important for battery internal resistance sizing but not for energy budget. 
 Average current: What actually matters for battery sizing. For a node that transmits 10 times per hour for 200ms at 100mA and sleeps (4mA) otherwise: average = (10 * 0.2s * 100mA + 3590s * 4mA) / 3600s = 4.05 mA average. 
 
 USB power loggers typically measure average current; this is what you want for battery sizing. Nordic PPK2 shows both. 

 Measuring nRF52840 Nodes (RAK4631, T-Echo) 
 # Using a 10-ohm sense resistor in series with the battery:
# 1. Insert 10-ohm resistor in series with battery positive terminal
# 2. Measure voltage across resistor with oscilloscope or slow multimeter
# 3. V = I * R: 50mV = 5mA, 100mV = 10mA, 800mV = 80mA

# Using Nordic PPK2:
# Connect PPK2 between battery and node
# Run nRF Connect Power Profiler software
# Record average current over 10-minute period for steady-state measurement
# Record peak current during LoRa transmission 

 Real-World Measurements (Community Data) 
 
 Node Mode Avg Current Battery Life (2500mAh) 
 
 RAK4631 MeshCore REPEATER Active repeating, 1 hop/min 12-15 mA 7-8 days 
 RAK4631 Meshtastic ROUTER Active, LongFast 10-14 mA 7-10 days 
 T-Beam ESP32 Meshtastic CLIENT Active, WiFi off 35-50 mA 2-3 days 
 T-Echo nRF52840 Meshtastic Power saving on 3-6 mA 17-35 days 
 Heltec V3 ESP32-S3 Active, WiFi off 25-40 mA 2.6-4 days 
 
 
 Note: Actual power consumption varies significantly with traffic load, transmit power setting, and environmental conditions (cold weather increases current draw).