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Wireless Solar charge controller monitor ( RS485 to WiFi using ESP 8266)

Picture of Wireless Solar charge controller monitor ( RS485 to WiFi using ESP 8266)

I've two solar charge controllers from EPsolar or EPever as they are sometimes known. They are great and have a COM port for monitoring the performance of the panels and state of the battery etc but it's a pain to drag the laptop out and hook things up just to check the status. The COM port is a RJ45 port which uses the RS485 standard so i investigated commercial offerings but they were extremely expensive and as this was just to make things convenient for a personal home product i didn't fancy paying £50 out for the privilege.

I began to investigate doing this myself and using some off the shelf components and custom firmware from the guys at esp-link i was able to come up with the design you can see in the picture.

Step 1: Flashing the ESP-8266

Picture of Flashing the ESP-8266

For the ESP-8266 i used a custom firmware

This puts the ESP-8266 into a transparent bridge mode so anything which is pushed to the RX or TX pins can be transmitted across WiFi. This allows connectivity so long as your in WiFi range. As your drawing power from the COM port it's feasible you could use a longer length of network cable to get it into a location for better WiFi reception if required. Flashing requires using the nodemcu software and flashing three seperate files onto the ESP-8266 at different offsets as per below

boot_v1.5.bin to 0x00000

blank.bin to 0x3FE000

user1.bin to 0x01000

I've attached a video showing the flashing process on windows with nodemcu and a Serial to USB adaptor based on the CH340 chipset. This also gives a short overview of what i'm trying to achieve and the process.



ESP-Link Firmware

tytower5 months ago
Gday I have a solar controller that I just want to have a look at whats coming out of it . Ive got heaps of arduinos and Max485 Rs-485 Module Ttl To Rs-485 Modules but want to run a twisted pair through wall and plug into USB on desktop . Can I do that? have you got time to guide me a bit?

Hi Colin,

Are you using plain vanilla ESP Link, or some variant of it?

From what I understand you wouldn't need to adapt it, or..?

ColinH4 (author)  mountaindude1 year ago

Hi I'm using straight ESP link,i have seen mention of RS485 support on the ESP link but that was after i made the instructable/wifi adaptor. Also i've not looked over the documentation but not sure how it can support it natively without an RS485 to serial adaptor in place.

LeeM961 year ago

hi mate any chance of a copy of the build in normal speed i think my wiring is wrong it hard to see so would like to here your comments.

im new to this both solar and electronics etc

thanks Lee

ColinH4 (author) 2 years ago
Just an update guys i found a simpler way for the software side
eplas3 years ago

Great hack!. I dit it too, It took me a while to figure out the ground problem too. It would be great for other users to put it the description too or adding the diagram. It works really well. Now I want to use one of the python epsolar libs to try to get data and push it to my emoncs web, under my centos linux home server.

OrvilleF1 eplas2 years ago

did you get this to work? I wan to do the same to push this to a web server?