Sonoff Smart Stackable Power Meter (Main Unit) - with battery

This stackable power meter realizes smart management with overload protection, metadata monitoring and electricity statistics.

- Connect up to 32 SPM-4Relays

One SPM-Main can be connected 32 SPM-4Relays. Each SPM-4Relay has 4 isolated channels to help you manage devices more conveniently.


- Power Meter

You can monitor the power consumption by checking eWeLink App on your mobile phone. Obtaining current, voltage and power easily.


- Max.20A/Gang

Each channel can support maximum current of 20A, no fear of high power load.

- Communicated by RS-485

The SPM-Main communicates with the SPM-4Relays through RS-485, which allows for multi-terminal and stable long-distance data transmission.


- Overload Protection

Once the overload protection is enabled, it can protect your devices from burning out.


- 128 Isolated Channels & Each Up To 20A

One SPM-Main can be connected 32SPM-4Relays.
Each SPM-4Relay has 4 isolated channels to help the
tenant to solve the problem in electric charge sharing.
Each channel can support maximum current
of 20A, no fear of high power load.


- Get Over 180-day of Energy Usage Data

Available SD card local storage. You can insert the
SD card into SPM-Main to download and check over
180 days of your energy usage history at any time of
the day through HTTP API. No need to worry about
missing the important information.
*Note: The only capacity supported is 8-32GB, SDHC card. The SD card is not included.


Note: The Main Unit and 4-Relay of the Stackable Power Meter need to be used together. The Main Unit is connected to at least one 4-Relay to function.