DC meter from Peacefair with RS485

[eazuka]

Having just read about the support for PZEM004T Energy Monitor from Peacefair. I'm just wondering if it will be possible to add support for PZEM-003 and PZEM-017 DC meter with RS485 from same manufacturer (Peacefair). I have use cases where Sonoff 4CH Pro, Sonoff SV & Shelly 1 will be used with PZEM-017 DC meter for DC (Solar) power metering and switching?

The PZEM-003 and PZEM-017 DC meter uses RS485 to communicate.

@arendst i can donate the PZEM-003 or PZEM-017 DC meter from Peacefair if you don't already have but think its possible to support it.

[gio-dot]

I'm quite sure that there you have to connect gnd and 3.3V coming from node mcu

[skeletik07]

I'm quite sure that there you have to connect gnd and 3.3V coming from node mcu

Yes! It's working now! Thanks a lot! And one last question, please. How i can save data with current and power for making daily graps? With MQTT brockers? Or it's some easy other way? Making graps i will be doing in excel or matlab, so i can save data in txt or some other text format.

[gio-dot]

I use home assistant to manage all domotic stuff.

[skeletik07]

But can i take exectly the digits of power and current in home assistant? Because i'm gonna do some research work with this data and i need power measurement every 3/5 seconds and saving this stuff somewhere i can operate with this

[rt45433]

I am using the pzem-017 and have got it working with tasmota. Just wanted to ask if there was a way to read the soc state or charge reading so I can use this through tasmato or have I missed it somewhere. I need this as I turn of my solar charger at 80% soc of the battery so want to see if I can did it using the pzem-017 and tasmota. Any help would be appreciated.

[gio-dot]

I am using the pzem-017 and have got it working with tasmota. Just wanted to ask if there was a way to read the soc state or charge reading so I can use this through tasmato or have I missed it somewhere. I need this as I turn of my solar charger at 80% soc of the battery so want to see if I can did it using the pzem-017 and tasmota. Any help would be appreciated.

It is not possible: soc calculation is very hard task that depend of a huge number of variables. It is not possible to calculate soc without knowing all those variables (battery type, battery capacity, battery state of healt, temperature, charge/discharge current, etc.)

[rt45433]

Thanks for the reply and information. I will use it with the data it currently has. Thanks again 👍 -)

[kittipongpoosri]

I need to code

[kittipongpoosri]

ฉันต้องการรหัสเพื่อใช้กับ esp8266

[Oleg-Sob]

Installed PZEM -017, everything works, the voltage shows an integer, tell me how you can make the voltage show with tenths or better hundredths.

[austrisv]

@Oleg-Sob it's VoltRes # https://tasmota.github.io/docs/Commands/

[Oleg-Sob]

Thank you very much, it worked out.

[Oleg-Sob]

It is not possible to calibrate the current in PZEM 017, it does not respond to the CurrentSet and CurrentCal commands. Tell me why.

[Oleg-Sob]

And the voltage fails to correct VoltageCal and VoltageSet does not respond, writes {"Command": "Error"}.

[seliku]

I am using the pzem-017 and have got it working with tasmota. Just wanted to ask if there was a way to read the soc state or charge reading so I can use this through tasmato or have I missed it somewhere. I need this as I turn of my solar charger at 80% soc of the battery so want to see if I can did it using the pzem-017 and tasmota. Any help would be appreciated.

It is not possible: soc calculation is very hard task that depend of a huge number of variables. It is not possible to calculate soc without knowing all those variables (battery type, battery capacity, battery state of healt, temperature, charge/discharge current, etc.)

Hi, I also have a PZEM-017 setup with a D1-Mini on my battery. Included are a tempsensor and 2 relays (heating-pads and fan). Throug rules Tasmota manages the health of the battery in addition of an BMS. The battery is getting charged from multiple sources. For example a charger hooked up to mains, solar panel charger and other small experimental generators. So far so good. Works like a charm.

My only wish would be that Tasmota + PZEM-017 would distinguish between charging and discharging. At the moment it only shows one (mixed) value. So if I am using 200 Watts and simultanious charging 50 Watts it shows 150 Watts. Or if I am using 50 Watts and charging 200 Watts it also shows 150 Watts.

Is my consuption correct that the only solution is to use two different sets (Tasmota + PZEM-017) for each discharging and charging and doing the maths through rules or externaly?

[Oleg-Sob]

You can use INA219 or INA226, they show both + and -.

[Oleg-Sob]

I use PZEM-17 to measure the charge of batteries, if used to measure charge and discharge, it summarizes everything as positive and it is not clear how much charge, how much discharge.

[seliku]

Thanks for the reply. I have those INAs but they are specified for small loads. Can I connect them to a 300A shunt?

It looks like INA226 should do the trick. Its worth a try. I will post my results here.

[Oleg-Sob]

Yes, you can, and calibrate the readings with the formula. The microcircuit measures the drop to 320 mV, a 300a 75mv shunt will give a drop of 225mV

[Oleg-Sob]

It is necessary to use INA219, 226 measures a drop of 80 mV

[seliku]

The INA219 meassures a max of 26V and has an internal shunt for max 3.2A As I understood the INA226 can be used with an external shunt and max 36V

[Oleg-Sob]

26v this voltage, if you need to measure a higher voltage, you can put a divider.

[Oleg-Sob]

The current is measured on the shunt, the INA 219 has a drop on the 320mV shunt for the INA 226 to 80mV, on the INA226 the maximum shunt can be put at 100A 75mV

[seliku]

I see. Then I will test this with the INA219. It would be wonderfull if this works. Thanks again

[jalakamkiranadspl]

Hey has anyone supposed to find the schematics of PZEM 004t I am not able to get it anywhere in the internet?

[Oleg-Sob]

Connection diagram, or electrical of the device itself?

[jalakamkiranadspl]

Electrical of the device itself

[Oleg-Sob]

I didn’t find either.

[jalakamkiranadspl]

I think I have found something. Actually a friend did. https://www.youtube.com/watch?v=qRsjsenvlJA Check this video out.

[ukewea]

how to connect PZEM 017 DC with nodemcu ?

I recently made a modification to make it possible to connect a PZEM-017 with ESP32 directly (i.e., without RS485 converter), here's what I've done:

• Remove the MAX485 chip.

• Solder wires from optocouplers to the terminal.

  • I soldered the wires to "R19" on the PCB as you can see in the picture below.
  • I forgot which one is Rx or Tx, try 2 times and you'll find the answer

Note: after modification, you must supply 3.3V to the terminal instead of the original 5V.

[austrisv]

Thank you @vicfergar for the original idea and @ukewea for follow-up. Very helpful! I got my 017 connected and looks like all good. I did disconnect only TX pin of MAX485 (was too lazy to remove the chip). I wonder, is it ok if I'm feeding the data side from ESP's 3V3 pin? Tested and it's working. Or shall I rather go with proper 5V from usb and 2k pulldowns? (power side will be 12V, just in case)

[ukewea]

Thank you @vicfergar for the original idea and @ukewea for follow-up. Very helpful! I got my 017 connected and looks like all good. I did disconnect only TX pin of MAX485 (was too lazy to remove the chip). I wonder, is it ok if I'm feeding the data side from ESP's 3V3 pin? Tested and it's working. Or shall I rather go with proper 5V from usb and 2k pulldowns? (power side will be 12V, just in case)

If someone's having similar question, a 3-month testing tells me that it's ok to feed the data directly from ESP, without pulldowns or anything else in between, and it's reporting data to my Home Assistant server nicely.

Also, I didn't put a resister between the TX of PZEM017 and ESP's RX.

[KNXfriend]

Thank you all for this great ideas and work!

I am currently prepring to monitor my boat´s batteries with this solution in the winterstock, while some systems stay up and online there. This is possible because of energy harvesting by solar panels and wind generator. But this includes the neccessarity to count not only one way. The batteries are charged over the day, while in the night the consumption typically is higher. So far I understand, that the PZEM 017 can only measure one way. That´s why I am thinking to take simply two, connect them to the same shunt, but one other way round connected. Since the PZEMs did not arrive so far, I cannot test it, but generally it should work. The only thing is - I don´t want to use an ESP for each.

Is there a way to enable the Tasmota software of one ESP to ask up to 4 different PZEMs over different modbus adresses? To give the different adresses to the PZEMs I found out so far.

The calculations about the energy balance sheet and taking Peukert factor into account would be calculated externally in the RasPI.

Target is a complete battery monitoring of service and starter batteries and the ability to manage the systems on the boat in dependency of the availability of energy.

[Oleg-Sob]

PZEM 017 measures the current in two directions, when there is a charge and the discharge, it counts everything with a + sign. Therefore, it will not be clear how much has been discharged, how much has been charged. Therefore, using two pieces will be useless.

[Oleg-Sob]

You can use INA 219, it measures in two directions with positive and negative readings.

[KNXfriend]

Thank you for this information. Now I will be aware, that this is possible. But from where you got this information? Because I find contradictory information in german forums. There it is described, that negative currents are floored to zero. Ina 219 looks promising beside that I liked the already hardened hardware for rough environment and the isolation over RS485, which can of course been realized with Ina 219 as well.

[barbudor]

You can have up to 3 PZEM max per tasmota. Also pzem and ina219 are very different things PZEM are for AC high voltage INA219 is for DC low voltage (max 30V)

[Oleg-Sob]

As for the PZEM 017, I also thought to put 2 pcs. in two directions, but it did not work out since they measure the negative current as positive. And I connected INA219 to a shunt of 100A and I measure the voltage 60V through a resistor divider 1/3, 20V comes to INA219, and in fact 60 and I adjust it with the formula.

[KNXfriend]

I understand, that my original plan might not work, like expected. I am still interested to understand, how to connect more than 1 PZEM to tasmota.

barbudor, can you enlighten me, how to connect up to 3?

I only understand to configure two GPIOs as serial interface for modbus PZEM communication. As far as I have seen, it seems that the modbus address for PZEM is hardcoded to 1 in the source code of tasmota. How to arrange, that tasmota is asking other adresses over the same bus? And why this is limited to 3?

[barbudor]

Searching a bit and you would have found https://github.com/arendst/Tasmota/discussions/10567

Up to know Tasmota has been designed for monitoring a single point of power. 3 is the maximum number of phases that you will encounter in real life.

[KNXfriend]

Ok. Then we are talking about different things. I am about battery monitoring, not about any ac or 3 phase applications.

Thank you for your fast answer.

That tasmota is currently designed for one connection to a PZEM corresponds to my still very little understanding of current solution.

I just wandered, if someone has ideas, how to use modbus as a real bus with tasmota and just ask several of this PZEM devices then only one.

I found a first hook in the source code, where tasmota communicates with exact this one PZEM adress and I might be able to extend this. But since I not really understand the whole tasmota architecture yet, I am afraid, I need some help.

[barbudor]

You asked about 3 PZEM, I told you:

• how to do that using 'ModuleAddress'. No need to extend Tasmota code as it is already supported
• what PZEM are meant for : AC, I'm 80% sure it won't work correctly for DC
• what is tasmota use case

To monitor batteries / DC, look at INA219/226 but be careful about ground management As fas as I remember only 1 of those is supported by ESP I know that someone on Discord is working on ina3221 driver which is a 3 channels. If it doesn't come quickly, I can do it too

[Oleg-Sob]

I have 2 pieces of PZEM 017 working. They work fine, I have not tried 3 pieces, but I think they will work.

[barbudor]

@Oleg-Sob Is that on AC or DC? If DC do you have to tell the PZEM about it (and how)?

[barbudor]

OK pzem017 is for dc My experience is with pzem004 which is ac

[Oleg-Sob]

PZEM 004 4 pieces work for me on one ESP 8266, though EspEasy firmware.

[grappini]

I have 2 pieces of PZEM 017 working. They work fine, I have not tried 3 pieces, but I think they will work.

What is the wiring diagram of the 2 pzem's with ESP 8266 ? Did you add the 2 pzem's to tasmota with ModuleAddress x command ?

[KNXfriend]

Ok. Seams that the feature is already existing up to 3 PZEMs. But your question grappini shows me, that not only I have problems to find this information.

I can still only guess, bcause I can not try, due to missing PZEMS. From the information what I think to understand now, there is the ModuleAddress 1/2/3 command, which probably sets the modbus adress to the PZEM device, which is currently on the bus.

When there are adress 1 and 2 or 1, 2 and 3 the tasmota automatically reads them all and represents them in the homescreen like seen above.(?)

That seams to be partially described in change log to 6.6.0.12 20190910 for me.

Thank you all, so activly helping here!

[ortegafernando]

I use PZEM-17 to measure the charge of batteries, if used to measure charge and discharge, it summarizes everything as positive and it is not clear how much charge, how much discharge.

Hi @Oleg-Sob @seliku what do you think about this option to "know" negative or positive values ? https://github.com/arendst/Tasmota/discussions/13733 Thanks

[Oleg-Sob]

Pzem 017 does not show negative currents, I use ina 226.