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.