As the PZEM-004T expects 5V serial data and the WEMOS D1 mini only provides up to 3V3 the expected optocoupler input power of the PZEM-004T has to be reduced. This can be accomplished by soldering a 1k resistor between the joints shown below.
for that part v1 is like v3
Connect the serial interface of the WEMOS D1 mini with the serial interface of the PZEM-004T.
- 3V3/5V Red
- Rx Yellow
- Tx Green
- Gnd Grey