Sensepriced
PZEM-004T v3 Power Meter
Peacefair · Shenzhen, CN
The cheapest true power metering module — V, A, W, PF, Hz, kWh. Removes the calibration guesswork of bare CT sensing (CT-only over-reads motors at PF 0.6–0.9).
Data out
TTL UART, Modbus-RTU protocol → ESP32 host → MQTT. Sibling PZEM-016 (~$12) speaks RS485 for multi-drop buses.
Price
¥23–34 Taobao (≈$3.5–5) · ~฿150 Shopee TH
- 22.9 CNY — Taobao listing →
- 150 THB — Shopee TH, split-CT variant
Sourcing
- Shopee TH · 1–3 days — many listings incl. Home Assistant bundles
Links
Gotchas
- Pick the split-core CT variant (clip-on); the closed-ring variant means threading the wire through
- Needs the L/N voltage tap for true metrics
- Needs an ESP32/host MCU — not standalone