I have a question. Can I also measure negative current with PZEM-017? I would like to measure the charging and discharging of a battery in a solar system with it.
Hello, it’s not like INA22x, it measure current/power only one way. Thus is useful to measure energy from PV panels, for example.
Just read the manual 
https://thesunpays.com/downloads/files/Battery%20SOC%20meters/PZEM-003%20017User%20Manual(MEDC300V).pdf
I’m using this power monitor with modbus integration, because haven’t found a way how to use this integration with RS485 adapter without automatic flow control, like standalone MAX485. It requires flow_control_pin. Any suggestions?
EDIT:
I’ve got it…
# ESP32 MAX485 PZEM-017
#
# GPIO10 DI
# GPIO20 RI
# GPIO21 DE+RE
# GND GND GND
# 3V3 VCC
# 5V 5V
# A A
# B B
uart:
baud_rate: 9600
data_bits: 8
stop_bits: 2
parity: NONE
tx_pin: GPIO10
rx_pin: GPIO20
modbus:
flow_control_pin: GPIO21
modbus_controller:
address: 30
i try to coment on patreon and i have to pay to do so so bad advertising
Did anyone has checked the accuracy of Pzem 017?
I’m using it with 50A shunt to monitor my solar installation in real time. And yes, I have programmed pzem 017 to use 50A shunt too. I have a mppt charge controller which also display on its screen the realtime voltage, current, power and kWh for the day. My setup has max current of 18.5 A, max voltage around 96V seen so far from panels.
The charge controller and pzem 017 kWh readings have differences. For production above 5 kWh, I have seen a difference of 4% (pzem 017 overreporting by approx 4% or charger underreporting by 4%) but below 2kWh, the difference is huge (pzem 017 overreporting by approx 25% or charger underreporting by 25%).
Pzem 017 claims to be accurate to 1% but without actual accuracy it is impossible to blame pzem 017 or mppt charge controller.
I don’t have a constant dc load on pzem 017, so I would like to know if someone has done some accuracy tests.
Here’s my approach to make it “natively” wireless 
GitHub - taHC81/pzem017-wireless: Built-in wireless functionality with ESP32-C3 and ESPhome
esphome:
name: pzem-017
esp32:
variant: ESP32C3
board: esp32-c3-devkitm-1
wifi:
networks:
- ssid: !secret wifi_ssid
password: !secret wifi_password
api:
ota:
logger:
uart:
baud_rate: 9600
data_bits: 8
stop_bits: 2
parity: NONE
tx_pin: GPIO10
rx_pin: GPIO20
sensor:
- platform: uptime
name: "PZEM-017 uptime"
update_interval: 30s
- platform: wifi_signal
name: "PZEM-017 WiFi Signal Sensor"
update_interval: 30s
- platform: pzemdc
address: 30
current:
name: "PZEM-017 Current"
voltage:
name: "PZEM-017 Voltage"
power:
name: "PZEM-017 Power"
energy:
name: "PZEM-017 Energy"
update_interval: 2s
switch:
- platform: restart
name: "PZEM-017 restart"
text_sensor:
- platform: wifi_info
ip_address:
id: ip_address
name: PZEM-017 IP Address
ssid:
name: PZEM-017 Connected SSID
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Remove that QC past sticker 
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Hey Sam, can you share a diagram or some knowledge on how to wire to get it working for monitoring direct solar panels
I managed to fry 2 units , I give them power from the USB port but I think this is not ok if you don’t have a special power brick or something ,give up 
How many ohm capacitor you replace for r3 and r5? Tks you
Hi, they’ve been burnt, so replaced with a same 10R (10 ohm). And these are resistors, not capacitors
That looks like a failed USB adapter, there’s a protection diode U6 to avoid mismatched + and - on USB, so it might be overvoltage. Or incorrect connection on a shunt side.