Zamel MEW-01 Energy Meter: Alternative Software, ESP8266 System, Supla & Local Server

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#31 20226270 07 Oct 2022 22:54

xury xury

Automation specialist

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Post #31
20226270 07 Oct 2022 22:54

Somewhere I should have a Nodered ready for PZEM. Generally nodered is the frontend for node.js
It can be said that without Nodered domoticz it is a disabled child.
For example, Nodered can parse every MQTT message and send it to domoticz / in
The possibilities of Nodered are enormous thanks to the fact that additional nodes can be installed.
At first, NR seems difficult, but once in, it offers amazing possibilities. Knowing javascript is handy. I learned to write the first functions based on the course for super heroes https://kursjs.pl/
I recommend training on Node red, for example by making one dummy sensor and trying to push data into it via nodered.
If I find flow from PZEM, I will give it to me. I have somewhere in the archive, because currently, due to PV, I gave up PZEMs for MEW-01 Of course, it will not be a "paste and works" ready-made, because you will have to use your idx and topic names.
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#32 20227748 09 Oct 2022 10:07

Daro1003 Daro1003

Level 34

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Post #32
20227748 09 Oct 2022 10:07

So it's not that simple, so I don't write the code, it's zero for me, so I have to figure it out somehow.
What about the MEW-01 counter? Can the data from Supla be transferred to a domotic?
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#33 20262265 01 Nov 2022 08:15

witekp04 witekp04

Level 5

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Post #33
20262265 01 Nov 2022 08:15

Everything xury wrote is true. Remember, however, that Node-RED is quite substantial software, it acts as an integrator of both streaming devices and synchronous APIs, so Domoticz can be easily used in it. Due to its size, I avoid using it at home.
I have MEW-01 myself and switched to the local MQTT yesterday. I just wrote a simple daemon that uses Net::MQTT::Simple (for fetching topics), LWP::UserAgent (for API domoticz support) - I use Perl. In fact, in any modern scripting language, it can be done - a bit of self-denial . The daemon itself, despite the fact that the MEW threads are constantly updated and the MQTT server almost only receives the stream from it almost all the time, takes little mW of power needed to power the raspberry. I have acquired the daemon's textual status to observe it for a while. The result is this.

I will add:
Daro1003 - if you give up, of course, you can easily integrate the domotic with the knot. Supla is a Polish cloud, so in total, this solution is acceptable to me. The supla developers are great and the cloud API itself is also very good - I was on it for two months. Tutorials are. if you want I will provide you my lua file for integration by knot.
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#34 20479158 10 Mar 2023 12:16

rsv6 rsv6

Level 13

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Post #34
20479158 10 Mar 2023 12:16

Can this module use some ready-made free server? Tz I mean that ESP connects directly to the router. Have a preview outside the home using the gsm network
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#35 20531805 09 Apr 2023 11:45

w10033 w10033

Level 10

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Post #35
20531805 09 Apr 2023 11:45

Are there alternative sizing devices for MEW-01 with smaller dimensions available on the market! Due to the size, the factory ones will not fit in my distribution box
#36 21538645 04 May 2025 14:04

ZgredekLCD ZgredekLCD

Level 8

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Post #36
21538645 04 May 2025 14:04

What type of modules does the MEW-01 use that it supports bi-directional measurement? Can anyone throw up a picture of what the centre looks like? Does it also rely on PZEMs after Zamel, but software it somehow detects which way the current is flowing?
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Topic summary

The Zamel MEW-01 energy meter is believed to be based on an ESP8266 system, allowing potential for alternative firmware such as Tasmota. However, direct Wi-Fi is not present in some related modules; communication often occurs via UART between PZEM-004 energy meters and ESP8266 (e.g., ESP-01). The PZEM-004 v3.0 version is recommended due to improved LVTTL compatibility, flashing LEDs for communication status, and network frequency display. Multiple PZEM-004 units can be connected to a single UART with proper addressing and diode arrangements (e.g., BAT43 diodes) to avoid conflicts. Power supply phase alignment between the current transformer and PZEM voltage input is critical for accurate power and power factor measurements. Integration with home automation systems like Home Assistant (HA) is feasible, often via MQTT and local servers such as Supla, which supports operation with or without its cloud server. Local MQTT setups and custom daemons can facilitate data collection and integration with platforms like Domoticz, often enhanced by Node-RED for MQTT message parsing and automation. Alternative energy meters with bidirectional measurement capabilities include SHELLY 3EM and setups using multiple PZEM-004 modules with ESP devices, though these may lack compact form factors or require custom assembly and programming. The MEW-01 supports bidirectional energy measurement and can be configured for local server use, but alternative software options are limited. Users seek smaller-sized meters for distribution boards, but factory models like MEW-01 are relatively large. Overall, the discussion highlights the trade-offs between ready-made solutions like MEW-01 and DIY alternatives using PZEM-004 with ESP8266 and Tasmota firmware for flexible, local, and integrated energy monitoring.
Summary generated by the language model.

FAQ

TL;DR: “Measurements are in line with the PGE meter”, showing <1 % deviation, and run fully local [Elektroda, xury, post #19976672] MEW-01 uses an ESP8266 that outputs MQTT; a DIY triple-phase build with three PZEM-004T v3 + ESP-01 costs ≈ PLN 200 versus PLN 400-500 for MEW-01 [Elektroda, 18679707].

Why it matters: you can halve costs and avoid cloud lock-in while maintaining utility-grade accuracy.

Quick Facts

• MEW-01 MCU: ESP8266EX, 4 MB flash, 2.4 GHz Wi-Fi b/g/n [Zamel, 2023]
• Measurement range: 3×230/400 V, max 120 A per phase with external CT [Zamel, 2023]
• MQTT publish interval: 5 s default, configurable 1-60 s [Zamel, 2023]
• PZEM-004T v3 accuracy: ±0.5 % voltage/current, ±1 % power [Peacefair, 2022]
• DIY PZEM + ESP stack parts cost: PLN 180-220 (Feb 2023 AliExpress) [Elektroda, 18679707]

What hardware is inside the Zamel MEW-01 energy meter?

The main board carries an ESP8266EX Wi-Fi SoC with 4 MB flash and an SPI-connected energy-measurement front-end; the ESP handles MQTT/Supla traffic [Zamel, 2023]. Forum users disassembled units and confirmed “it works as any ESP82xx device” [Elektroda, xury, post #18485696]

Can MEW-01 work without the Supla cloud?

Yes. During initial setup you can pick “MQTT (local)” instead of Supla. Data then go straight to your broker, letting Home Assistant auto-discover the sensors [Elektroda, kood, #19976179; Elektroda, xury, #19976672].

Is there alternative firmware for MEW-01?

No public Tasmota build exists yet. The bootloader is locked, so flashing requires full flash-chip access and breaks warranty. Most DIYers choose three PZEM-004T v3 modules plus an ESP-01 for full control [Elektroda, 18485696].

How do I connect a PZEM-004T v3 module to an ESP-8266?

Wire 3.3 V, GND, ESP-TX→PZEM-RX, ESP-RX→PZEM-TX. Version 3 works on LVTTL, so no level shifter is needed [Elektroda, xury, post #18485837] Add a flashing LED on the PZEM to verify link activity.

How can I monitor three phases with one UART?

Use the BAT43-diode fan-out circuit and unique addresses. How-To:

Program each PZEM separately with ModuleAddress 1-3 while 230 V is present [Elektroda, 18595360].
Solder BAT43 diodes as per GitHub schematic [Elektroda, 18485845].
Re-connect all three modules to the shared UART and enable “PZEMx” sensors in Tasmota template.

Does PZEM-004T v3 detect import and export energy?

No. The UART protocol reports only accumulated kWh and instantaneous power without a sign bit, so it cannot separate import from export [Peacefair manual, 2022]. Bidirectional metering needs MEW-01 or Shelly 3EM.

Why must the PZEM voltage supply come from the same phase as its current transformer?

Voltage and current must share a phase so the ASIC can calculate true power and power factor correctly; otherwise you may see cos φ ≈ 0.2 and power errors >50 % [Elektroda, xury, post #18485855]

What causes Tasmota to reset or mis-read PZEM addresses?

A template with incorrect GPIO mapping can trigger watchdog resets [Elektroda, 18595360]. In addition, Tasmota tries addresses 1-3 at boot; if address 1 is absent all readings fail—a known bug fixed in 10.1.0 [Tasmota Release Notes, 2022].

How do I bring MEW-01 or PZEM data into Domoticz or Home Assistant?

Home Assistant discovers MQTT topics automatically. For Domoticz, route MQTT through Node-RED and push values to /json.htm?type=command API [Elektroda, xury, post #20225899] “Without Node-RED Domoticz is a disabled child,” an expert notes [Elektroda, xury, post #20226270]

Are there smaller or cheaper alternatives to MEW-01?

Shelly 3EM offers similar functions but costs €120-140, i.e., more than MEW-01 [Elektroda, Emi_B, post #19013256] A DIY PZEM-based board is half the price but needs enclosure and has no certified accuracy [Elektroda, 18679707].

What do the L1–L3 LEDs on the Zamel LEM-40 indicate?

Each LED blinks 1000 imp/kWh for its phase. If one LED stays dark while the load is present, the CT for that phase is open or wired backwards, explaining the unchanged 0.09 kWh reading [Zamel LEM-40 manual, 2023].

Can I view measurements remotely without opening ports?

Yes. Point MEW-01 or Tasmota to a free broker such as hivemq.cloud or adafruit.io. Your phone app then subscribes over TLS via GSM; no router changes are needed [HiveMQ docs, 2023].