Power and batteries

ZiggyMeter runs from two AAA cells or from USB-C. Which one you choose determines almost everything else about how the device behaves: how often it can read, whether the web interface is always available, and which radio makes sense.

The two modes

	Batteries	USB-C
Supply	2 × AAA (LR03/R03), 1.2–1.5 V	5 V, 5 W
Between readings	Deep sleep	Awake
Web interface / API	On demand only	Always available
Recommended radio	Zigbee	Wi-Fi or Zigbee
Typical schedule	4–24 hours	1 minute – 1 hour

If both are present, the device automatically uses USB-C and leaves the batteries alone.

Battery power

For installations where there is no socket near the meter — which is most of them.

• Deep sleep. After each reading the device powers down almost everything and wakes on the schedule or on a button press. While asleep the LEDs are off and it does not answer on the network.
• Use Zigbee. Wi-Fi needs far more energy per exchange than Zigbee, and it needs to associate with an access point every time. Running Wi-Fi on batteries drastically shortens their life.
• Alkaline for cold places. Standard alkaline cells cope with low temperatures better than NiMH rechargeables, which lose capacity quickly in the cold. Meter cabinets on an outside wall get cold.

Even on Zigbee you can still bring Wi-Fi up temporarily — hold the button for 3 seconds — to reach the web interface or the API.

What actually drains the batteries

In descending order:

1. Reading frequency. Every readout wakes the radio and the optical driver.
2. The radio in use. Wi-Fi costs substantially more per exchange than Zigbee.
3. Wi-Fi left on. Set the power-saving mode so the device is allowed to sleep.
4. Poor signal. A weak link means retries, and retries mean radio time. See Antenna and signal.

Halving the reading frequency is the single most effective change you can make.

USB-C power

For continuous monitoring and frequent updates, power the device from any standard USB-C supply — a phone charger is plenty.

• Always online. The device stays awake, so the REST API and web interface are reachable at all times.
• Preferred with Wi-Fi. If you want Wi-Fi, use USB-C.
• Power banks work, but see the power-saving note below.

Power-saving mode

System → Power saving mode controls whether the device sleeps between readings.

Mode	Behaviour	Use it when
Auto	Default. Sleeps on battery, stays awake on USB.	Almost always
Always	Sleeps regardless of power source.	Running from a power bank. In Auto the device assumes anything on USB-C is mains power and stays awake, which flattens a power bank; Always makes it sleep between readings anyway.
Never	Never sleeps, even on batteries.	Temporary debugging only

WARNING

Never on battery power will flatten a pair of AAA cells in a matter of hours. It exists for bench work, not for installation.

Set it in the web interface, or through POST /api/v1/system/power_mode.

Monitoring the supply

The Dashboard shows both inputs:

• Battery voltage — 0.00 V means no cells fitted, or fully discharged
• USB voltage — around 5 V when a supply is connected
• Device temperature — the internal sensor, useful for checking a hot cabinet

The same values are available from GET /api/v1/system/status, including a battery_powered flag, so you can alarm on it from Home Assistant.

Over Zigbee, battery state is reported through the standard Power Configuration cluster (0x0001) on endpoint 1, which most coordinators surface as a battery sensor.

Practical setups

Situation	Recommended
Socket in the meter cabinet	USB-C + Wi-Fi, 1 hour schedule
No socket, Zigbee coordinator in range	Batteries + Zigbee, 4–24 hour schedule
No socket, no Zigbee	Batteries + Wi-Fi, 24 hour schedule, expect short battery life
Temporary diagnosis	USB-C + Wi-Fi, 1 minute schedule