The arduino R4 shows D0 and D1 as being TX/RX, but I’ve tried with other pins with no success.
Should I expect the TX LED of the pzem flash to blink when not connected, or nothing until connection is established?
Thanks, I only have one LED come up. Waiting for a UART TTL->USB cable tomorrow to try to diagnose with the PC.
Did you get the v4 working?
Hello, my pzem-004T v3 was working perfectly with Home Assistant. I updated esphome builder to 2025.08 and all the sensors were showing as unknown. I reverted to esphome builder version 2025.06 and the sensors are now giving correct readings. Could something have changed in the pzem-004t v3 configuration? help me. I have the following:
esphome:
name: consumo-electrico-esp32
friendly_name: Consumo electrico esp32
esp32:
board: esp32dev
framework:
type: arduino
# Enable logging
logger:
# Enable Home Assistant API
api:
encryption:
key: "My key"
ota:
- platform: esphome
password: "my pass"
wifi:
ssid: !secret wifi_ssid
password: !secret wifi_password
# Enable fallback hotspot (captive portal) in case wifi connection fails
ap:
ssid: "Consumo-Electrico-Esp32"
password: "my pass"
captive_portal:
uart:
rx_pin: GPIO1 # cable verde
tx_pin: GPIO3 # cable blanco
baud_rate: 9600
stop_bits: 1
# Configuracion PZEM-004T V3
modbus:
sensor:
- platform: pzemac
id: pzemac_1
current:
name: "P Corriente"
voltage:
name: "P Voltaje"
energy:
name: "P Energia"
power:
name: "P Potencia"
frequency:
name: "P Frecuencia"
power_factor:
name: "P Factor de Potencia"
update_interval: 1s
2025.10 (latest) integrated a change regarding pzem, but not marked as breaking 
Logs from the not working setup would be fine 
Well done @nitin29 . Could you please explain the connections in your 2nd picture. I am planning to do something similar . Would like to monitor three phases along with inverter backed power supply running all the DC electronics and also be able to measure 0v ( monitor power outages) . Any suggestion is welcomed. Thanks.
hi,
I was having problems with my PZEM and ESPHome build from September 2025, and got no response, but just updated to 2025.11.2 and started working perfectly using your code. You may want to try it. Good luck!
wifi:
ssid: !secret wifi_id
password: !secret wifi_pw
ap:
ssid: $devicename
password: "1122334455"
substitutions:
devicename: 3phase-power-monitor
friendly_name: Power Monitor
esphome:
name: ${devicename}
friendly_name: ${friendly_name}
name_add_mac_suffix: false
project:
name: esphome.web
version: "1.0"
esp8266:
board: esp01_1m
logger:
baud_rate: 0 # free UART for PZEM
level: DEBUG # change to INFO later
wifi:
ssid: "bespoq"
password: "E1F01C3AEE"
reboot_timeout: 15min
power_save_mode: none
ap:
ssid: ${devicename}
password: "1122334455"
ota:
- platform: esphome
api:
web_server:
port: 80
version: 3
dashboard_import:
package_import_url: github://esphome/example-configs/esphome-web/esp8266.yaml@main
import_full_config: true
time:
- platform: homeassistant
id: homeassistant_time
uart:
tx_pin: GPIO1
rx_pin: GPIO3
baud_rate: 9600
stop_bits: 1
parity: NONE
# Increased modbus timing to prevent bus contention
modbus:
id: mod_bus_pzem
send_wait_time: 2000ms # 2 seconds between requests
binary_sensor:
- platform: status
name: "${devicename} Status"
text_sensor:
- platform: wifi_info
ip_address:
name: "${devicename} IP Address"
ssid:
name: "${devicename} Connected SSID"
mac_address:
name: "${devicename} MAC Address"
sensor:
- platform: wifi_signal
name: "${devicename} WiFi Signal"
update_interval: 60s
- platform: uptime
name: "${devicename} Uptime"
# --------- PHASE L1 ----------
- platform: pzemac
id: pzemac1
address: 1
modbus_id: mod_bus_pzem
update_interval: 90s # Long interval, controlled by automation
current:
name: "Current L1"
id: current_l1
voltage:
name: "Voltage L1"
id: voltage_l1
energy:
name: "Energy L1"
id: energy_l1
device_class: energy
state_class: total_increasing
unit_of_measurement: "Wh"
power:
name: "Power L1"
id: power_l1
device_class: power
state_class: measurement
frequency:
name: "Frequency L1"
id: frequency_l1
power_factor:
name: "Power Factor L1"
id: pf_l1
# --------- PHASE L2 ----------
- platform: pzemac
id: pzemac2
address: 2
modbus_id: mod_bus_pzem
update_interval: 90s
current:
name: "Current L2"
id: current_l2
voltage:
name: "Voltage L2"
id: voltage_l2
energy:
name: "Energy L2"
id: energy_l2
device_class: energy
state_class: total_increasing
unit_of_measurement: "Wh"
power:
name: "Power L2"
id: power_l2
device_class: power
state_class: measurement
frequency:
name: "Frequency L2"
id: frequency_l2
power_factor:
name: "Power Factor L2"
id: pf_l2
# --------- PHASE L3 ----------
- platform: pzemac
id: pzemac3
address: 3
modbus_id: mod_bus_pzem
update_interval: 90s
current:
name: "Current L3"
id: current_l3
voltage:
name: "Voltage L3"
id: voltage_l3
energy:
name: "Energy L3"
id: energy_l3
device_class: energy
state_class: total_increasing
unit_of_measurement: "Wh"
power:
name: "Power L3"
id: power_l3
device_class: power
state_class: measurement
frequency:
name: "Frequency L3"
id: frequency_l3
power_factor:
name: "Power Factor L3"
id: pf_l3
# --------- DAILY ENERGY PER PHASE (kWh) ----------
- platform: total_daily_energy
name: "Energy L1 Daily"
power_id: power_l1
id: energy_l1_daily
unit_of_measurement: kWh
accuracy_decimals: 3
filters:
- multiply: 0.001
- platform: total_daily_energy
name: "Energy L2 Daily"
power_id: power_l2
id: energy_l2_daily
unit_of_measurement: kWh
accuracy_decimals: 3
filters:
- multiply: 0.001
- platform: total_daily_energy
name: "Energy L3 Daily"
power_id: power_l3
id: energy_l3_daily
unit_of_measurement: kWh
accuracy_decimals: 3
filters:
- multiply: 0.001
# --------- CALCULATED TOTAL SENSORS ----------
- platform: template
name: "Total Power"
id: total_power
device_class: power
state_class: measurement
unit_of_measurement: W
accuracy_decimals: 1
update_interval: 30s
lambda: |-
float p1 = id(power_l1).state;
float p2 = id(power_l2).state;
float p3 = id(power_l3).state;
if (isnan(p1) || isnan(p2) || isnan(p3)) {
return NAN;
}
return p1 + p2 + p3;
- platform: template
name: "Total Energy"
id: total_energy
device_class: energy
state_class: total_increasing
unit_of_measurement: kWh
accuracy_decimals: 3
update_interval: 30s
lambda: |-
float e1 = id(energy_l1).state;
float e2 = id(energy_l2).state;
float e3 = id(energy_l3).state;
if (isnan(e1) || isnan(e2) || isnan(e3)) {
return NAN;
}
float total_wh = e1 + e2 + e3;
return total_wh * 0.001;
- platform: template
name: "Total Daily Energy"
id: total_energy_daily
device_class: energy
state_class: total_increasing
unit_of_measurement: kWh
accuracy_decimals: 3
update_interval: 30s
lambda: |-
float e1 = id(energy_l1_daily).state;
float e2 = id(energy_l2_daily).state;
float e3 = id(energy_l3_daily).state;
if (isnan(e1) || isnan(e2) || isnan(e3)) {
return NAN;
}
return e1 + e2 + e3;
button:
- platform: restart
name: "${devicename} Restart"
- platform: template
name: "Reset Energy L1"
on_press:
then:
- pzemac.reset_energy: pzemac1
- platform: template
name: "Reset Energy L2"
on_press:
then:
- pzemac.reset_energy: pzemac2
- platform: template
name: "Reset Energy L3"
on_press:
then:
- pzemac.reset_energy: pzemac3
# SEQUENTIAL POLLING - Critical fix for bus contention
# Poll Phase 1 every 30 seconds
interval:
- interval: 30s
then:
- component.update: pzemac1
# Poll Phase 2 every 30 seconds, but offset by 10 seconds
- interval: 10s
then:
- delay: 10s
- component.update: pzemac2
# Poll Phase 3 every 30 seconds, but offset by 20 seconds
- interval: 20s
then:
- delay: 20s
- component.update: pzemac3
Have assigned unique ID’s for all 3 PZEMs
Individually, I’m able to read them in their respective IDs
But when connected altogether, they are not working
One observation from PZEM LED status is that all PZEMs transmit together, same with receiving too
Hardware Setup
Wemos D1 Mini
PZEMs are directly connected to TX-RX (parallel connection with no pullup resistor or diode)
Any support will be invaluable 
When you say “parallel connection with no pullup resistor or diode”, I assume you mean you haven’t added anything.
Each Rx and Tx line on each PZEM board has a pull-up resistor and an LED.
If you wire them all directly in parallel then:
The Tx from the MCU will be driving 3 PZEM Rx lines at the same time: about 21mA
And the Tx line of each PZEM will be trying to drive the MCU pull-up, it’s pull-up and LED AND the other two Tx lines as well!: > 21mA
From what I could find, the max output current of the Tx pin on the D1 Mini is 12mA.
So the MCU can’t Tx to all three at the same time without adding a transistor or removing pull-ups from the 2 of the PZEM boards. (If they are in parallel then you only need one pull-up, not three in parallel, same for LEDs.)
The CT817 opto on the PZEM can handle 50mA, so for 3 PZEMs in parallel it should be ok.
I am running 9 in parallel from a ESP8266 NodeMCU with these mods…
- Pull-up resistors and LEDs removed from all but one PZEM
- A BC557 PNP transistor to boost the Tx line current
esphome:
name: switchboard
friendly_name: switchboard
esp8266:
board: esp01_1m
# Disable UART logging as it interferes with pzem)
logger:
baud_rate: 0
level: NONE
# Enable Home Assistant API
api:
encryption:
key: "-some-big-encryption-key-here-"
ota:
- platform: esphome
password: !secret ota_password
- platform: web_server
wifi:
ssid: !secret my_wifi_ssid
password: !secret my_wifi_pwd
ap:
ssid: $friendly_name
password: !secret ap_password
# manual_ip:
# static_ip: 192.168.0.150
# gateway: 192.168.0.1
# subnet: 255.255.255.0
captive_portal:
web_server:
mdns:
uart:
- id: com1
tx_pin: GPIO1
rx_pin: GPIO3
baud_rate: 9600
data_bits: 8
stop_bits: 1
parity: NONE
modbus:
- id: mod_bus_pzem1
send_wait_time: 250ms
uart_id: com1
sensor:
- platform: pzemac
id: CB1
current:
name: "CB1 Current"
voltage:
name: "CB1 Voltage"
energy:
name: "CB1 Energy"
power:
name: "CB1 Power"
update_interval: never
address: 1
modbus_id: mod_bus_pzem1
- platform: pzemac
id: CB2
current:
name: "CB2 Current"
voltage:
name: "CB2 Voltage"
energy:
name: "CB2 Energy"
power:
name: "CB2 Power"
update_interval: never
address: 2
modbus_id: mod_bus_pzem1
- platform: pzemac
id: CB3
current:
name: "CB3 Current"
voltage:
name: "CB3 Voltage"
energy:
name: "CB3 Energy"
power:
name: "CB3 Power"
update_interval: never
address: 3
modbus_id: mod_bus_pzem1
- platform: pzemac
id: CB4
current:
name: "CB4 Current"
voltage:
name: "CB4 Voltage"
energy:
name: "CB4 Energy"
power:
name: "CB4 Power"
update_interval: never
address: 4
modbus_id: mod_bus_pzem1
- platform: pzemac
id: CB5
current:
name: "CB5 Current"
voltage:
name: "CB5 Voltage"
energy:
name: "CB5 Energy"
power:
name: "CB5 Power"
update_interval: never
address: 5
modbus_id: mod_bus_pzem1
- platform: pzemac
id: CB6
current:
name: "CB6 Current"
voltage:
name: "CB6 Voltage"
energy:
name: "CB6 Energy"
power:
name: "CB6 Power"
update_interval: never
address: 6
modbus_id: mod_bus_pzem1
- platform: pzemac
id: CB7
current:
name: "CB7 Current"
voltage:
name: "CB7 Voltage"
energy:
name: "CB7 Energy"
power:
name: "CB7 Power"
update_interval: never
address: 7
modbus_id: mod_bus_pzem1
- platform: pzemac
id: CB8
current:
name: "CB8 Current"
voltage:
name: "CB8 Voltage"
energy:
name: "CB8 Energy"
power:
name: "CB8 Power"
update_interval: never
address: 8
modbus_id: mod_bus_pzem1
- platform: pzemac
id: CB9
current:
name: "CB9 Current"
voltage:
name: "CB9 Voltage"
energy:
name: "CB9 Energy"
power:
name: "CB9 Power"
update_interval: never
address: 9
modbus_id: mod_bus_pzem1
interval:
- interval: 10s
then:
- delay: 500ms
- lambda: "id(CB1).update();"
- delay: 500ms
- lambda: "id(CB2).update();"
- delay: 500ms
- lambda: "id(CB3).update();"
- delay: 500ms
- lambda: "id(CB4).update();"
- delay: 500ms
- lambda: "id(CB5).update();"
- delay: 500ms
- lambda: "id(CB6).update();"
- delay: 500ms
- lambda: "id(CB7).update();"
- delay: 500ms
- lambda: "id(CB8).update();"
- delay: 500ms
- lambda: "id(CB9).update();"