Smart Meter (AMS) Readers

01What is an AMS reader?

An AMS reader (also called HAN port reader) is a small hardware device that plugs into the HAN port on the back of your Norwegian smart meter. It decodes the live data stream the meter already broadcasts - your real-time power draw, voltage and reactive power - and forwards it to Wattoshi over your home WiFi.

Without an AMS reader, Wattoshi only sees a delayed value (15 min – 24h depending on your grid company). With a reader you get per-second resolution, which is what Peakstop, smart-plug automation and accurate savings are built on.

02How it works

The data path looks like this:

1. The AMS meter broadcasts a HAN-PDL / COSEM-formatted telegram every 2–10 seconds.
2. Your reader connects to the meter's local web server (typically http://192.168.1.1) and pulls the latest list.
3. The reader parses the telegram, picks out the active power (W) and energy counters, and signs the payload with a device key.
4. It POSTs the payload to https://api.wattoshi.com/ingest/ams via your local WiFi.

Wattoshi then aggregates the stream into 1-second, 1-minute and 1-hour buckets and exposes it through the dashboard and any connected devices (smart plugs, heaters, Bitcoin miners).

03Why you need one

• Accurate savings. Peakstop can only react to spikes if it sees them in real time.
• Better earnings. Sat-savings are calculated against actual avoided kWh, not estimates.
• No surprises. Live anomaly detection catches runaway loads (e.g. a faulty heater) within seconds.
• Solar pairing. Match solar production to household draw in real time and route surplus to a miner.

04Compatible readers

Wattoshi works with any reader that speaks the Norwegian HAN protocol. The three most common are:

05Setup in 4 steps

1. Activate the HAN port. Log in to your DSO's self-service portal (Elvia / BKK / Glitre) and request access. Activation usually takes 24–48 h.
2. Plug in the reader. Connect it to the HAN port on the back of the AMS meter. Most readers have a small LED that turns green when paired.
3. Pair with Wattoshi. In the app go to Devices → Add → AMS Reader and scan the QR code on the back of the reader. WiFi credentials are pushed automatically via BLE.
4. Verify the stream. The dashboard should show live kW within 30 seconds. If not, see troubleshooting below.

06Troubleshooting

No data after 5 minutes. Check the HAN port is activated. The reader's LED should be solid green; red or off means no power or no port.

Reader drops out randomly. Most often a WiFi range issue. Move the router closer to the meter or add a mesh node. The POW-U has a small external antenna for this.

Numbers look wrong (negative, off by 10×). The meter telegram uses OBIS codes; some older readers mis-parse the active-power field. Update the firmware in the Wattoshi app (Devices → AMS Reader → ⋯ → Update).

07Common questions

Does it work with all Norwegian meters? All Aidon, Kaifa and Landis+Gyr AMS meters deployed after 2017 expose a HAN port. Some older Kamstrup meters (pre-2017) need an adapter.

Is the data private? Yes. The stream goes reader → Wattoshi over signed HTTPS. We never sell or share consumption data, and you can self-host via Home Assistant if you prefer.

Can I use two readers at once? Yes, but you only need one. A second reader is useful for redundancy if you run mission-critical loads (e.g. a server rack).