Build Your Own RS485 to Wifi Adapter for EPEver Solar Charge Controllers

Posted on 29/12/2017 by Adam

Many EPEver solar charge controllers have an RS485 communication port on them so you can connect a PC or Android device and read it’s statistics or update the settings.

Although EPEver have themselves developed a wifi adapter for the solar charge controllers which support RS485 it has some flaws which makes it less useful than it could have been. Recent versions of the software have prevented the EPEver eBox Wifi-01 from connecting to normal wifi networks entirely although it had been implemented in early firmware versions.

Other commercial RS485 to wifi adapters do exist but typically they tend to cost more than the eBox and draw more current – not ideal for a solar charge controller.

Colin Hickey decided that there must be another option and after much research and a few dead ends found the open source ESPLink software by jeelabs. This allows the popular ESP8266 to easily become a wifi to serial bridge. Now he just needed a serial to RS485 solution which came in the form of the XY-017 TTL to RS485 module which is widely available on eBay.

Colin talks about the journey and his solution for the EPEver solar charge controllers in this series of videos.

DIY RS485 wifi Adaptor Playlist

After dabbling with this design using perfboard, Adam Welch thought it might be an opportunity to take his first plunge into designing a custom PCB and have some boards manufactured to allow easier connection of the components, and to his surprise they seem to have worked quite well!

Colin Hickey is selling completed built and flashed units ready to plug in and connect to your wifi network.  You can buy them soon.

Components required:
RS485 to ESP8266 PCB: http://admw.uk/kh (Zipped Gerber File)
ESP8266 ESP-01: https://goo.gl/HGJZL7
XY-017 RS485 to TTL Module: https://goo.gl/nEFZsc
RJ45 Network Cable: https://goo.gl/2UAR78
Pin Header: https://goo.gl/gNxgzb

Assembly is very simple – just follow the silkscreen on the PCB and the following colour code for the network cable. (The assumption is you’re re-purposing a standard network cable)

Orange Solid – Vcc (V)
Green Stripe – RS485 B (B)
Green Solid – RS485 A (A)
Brown Solid – Ground (G)
The other four wires may be cut short and isolated.

Flashing the ESP with ESPLink firmware is quite straight forward.  Download ESPLink (I suggest using version 2.2.3) and extract the contents of the tar file to your hard drive (7zip is a good option to untar).  Download the NodeMCU Flasher program and configure it as shown below.

 

 

 

 

 

 

 

Finally plug in your ESP8266 into your programmer and plug it into your PC.  Choose the correct COM port on the Operation tab and click Flash.

What Others Are Saying

  1. Ed 17/01/2018 at 22:35

    When the completed units are available could you please post a link or otherwise make it known? I am very interested in getting one. I figure by the time I collect all the pieces parts, figure out how to screen a pcb, etc. he will have some for sale. 🙂

  2. Paul 20/01/2018 at 20:05

    Hi Adam,

    Thought you might be interested in this:
    http://www.eevblog.com/forum/projects/nodemcu-esp8266-rs485-epever-solar-monitor-diy/msg1404831/#msg1404831

    Inspired by yourself and the linked video.

    The bit you might be more interested in is the data logger. Runs on a raspberry PI (or PC). I just send it data in a particular format and it logs it once a minute. Could be panel voltage, outside temperature, anything. Graphs can be generated from the data archives easily.

    • Adam 13/02/2018 at 20:04

      Neat – thanks for posting the link and sorry for the delay in replying. Might have to take a look at that in a bit more detail. Cheers

  3. Dieko 02/04/2018 at 14:21

    Hi Adam,
    thanks for all your efforts and thanks for sharing your project!

    I have a setup with the EPEVER eBox-wifi in station mode in my WLAN talking to my raspberry. It works via socat and the toggio php scripts.

    But: Somehow I lose connection to the eBox device and I have to un- and replug the cable to restart it.

    Before I go for soldering your solution I would be interested to buy your device. How far is the production plan ? 🙂

    Best regards and Happy Easter everybody…

  4. Jim Ryan 04/04/2018 at 22:03

    Aloha from Hawaii! Love this project…

    I just installed a system containing a 175W 24V solar panel, RioRand/Epever Solar Charge Controller RR2210RN and 2x6V deep-cycle golf cart batteries in series. This project would be a great match for my PV system.

    Are you still thinking about selling your PCB or finished product? Are your schematics/code available?

    Also, I am thinking about updating the ESP8266 to an ESP32, and posting PV and battery SOC data to an IoT service via MQTT for remote monitoring. Any ideas here would be helpful.

    Mahalo, Jim

  5. Joe 28/05/2018 at 19:41

    awesome project.
    First of all, i’m new to all of this so not sure what i’m doing. I downloaded the gerber files and went to allpcb to order pcb boards but they need lots of other parameters before even allowing me to upload file. I was wondering if you had all the info for pcb just like yours? This is the info they said i would need along with gerber file. https://media.trillian.im/media/?m=aW1hZ2UvanBlZyw2NjgsNzQzLJT%2FDPYF5a7BlEBNGM1pYCQIGNvYo9f4LYLDgQeEX7A0.
    Thanks fore your time

    • Adam 12/06/2018 at 20:20

      All the defaults should be fine – 2 layer, 1.6mm thick, green boards, white printing etc. The gerber file will dictate the size of the PCB so for this step just pop in 50mm x 50mm and ten pieces cost the same as one typically. Hope that helps.

      • Joe 14/07/2018 at 04:30

        Thanks. That worked and i have the boards. Now just need to get it working on the “AN” negative ground models. Thanks again for your time.

Leave a Reply to Adam Cancel reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.