A flashing green LED is good. It might be something completely unrelated - can you look at the Javascript console (F12) on the web interface to the DIYBMS - do you see any errors?
I’m having similar issues. Provisioned one. Saw the graph, navigated a few screens, then the graph disappeared and I couldn’t get it to provision again. I rebuilt my wemos on a breadboard with better connections and switched the USB power to a USB battery backup since it seems like the cleanest supply. (Getting rid of any noise).
Now I have the wemos connected to the cell module. They flash in rhythm with each other and the cell module never goes into panic unless I pull the I2C connector. However, nothing shows on the web interface.
I will probably just reinstall the sketch on both and start over unless there is some way to factory reset the wemos to clear the old provisioned cells?
I also might try a higher pull-up resistor. I have a crappy kit scope, but it doesn’t look like a nice square packet.
As I mentioned above I think this is a problem with the web console rather than the modules, take a look at the CONSOLE window in Chrome development window F12 whilst the web interface loads up. See if any errors appear.
Oh no, it’s getting worse. Now some of the buttons don’t navigate it all. Maybe the wemos’ memory is corrupted.
Console says:
Unable to get property ‘config’ of undefined or null reference loader.js (396,3)
Module 2 soldered up, programmed and provisioned, same story. But there is a error in Chrome F12, console!
Failed to load resource: the server response with a status 404 (not found)…1563134355507333524378587151298|374x500
The 404 error is probably a false error, you often see these with the wemos devices as they don’t have much processing power for web serving.
The previous error about config looks more relevant.
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I’m going to reflash the controller sketch when I get off work tonight. I have a feeling some setting file got corrupted. Maybe it lost power while updating something? Update to come.
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Sorry for the long post, but hopefully someone might find something useful in my struggle. not that it’s much of a struggle because I love doing this crap. 
Reinstalling the wemos worked! I did have a hiccup putting the previously provisioned module back on. It wouldn’t show when I hit Provision. So, instead, I put a fresh cell module on provisioned it. Strangely, two cells showed up, both @ ID-24 even though I only had one connected.
So I connected the previously provisioned cell module onto the chain to see if it would do anything. Of course, both being assigned 24 that didn’t work. I “Factory Reset” both modules and gave it a minute to make sure it was done. I connected just one module (now with a solid green light) and provisioned. It worked, but now it showed 3 modules @ ID-24, but only one showed voltage and temperature so I thought I’d press on and worst-case worse reinstall all the sketches after more troubleshooting.
I added the second cell module and provisioned it. I then had a module at ID-24 and a module at ID-25 both showing voltage and temperature. The other phantom cells were still there, but I had solid progress.
Before going to reinstall all the sketches, I decided to follow the IT Crowd mantra: Have you tried turning it off and on again? I selected the Reset Controller button on the home page, and when the Wemos reconnected, the phantom cells were gone!
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From memory, the controller only scans for the modules at power on/reset. So if you had 2 modules with the same address it would have got confused.
Glad you got there in the end!
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hello all, thought i had 14 modules done but for some unknown reason one is now unable to provision. So i have 13 modules needing 14.
i have measured all voltages at each component, see attached sheet.
I measured 2 of the boards that wont provision and all reading are the same as a factory setting as a module that can be provisioned.
U2 reading 1 2.0v 2. 2.0v 3. 0v 4. 0v 5 .0v 6 3.3v 7 3.3v 8 3.3v same as the provision module.
Nothing is wrong with my wemos as it find the module i measured the voltages from.
Anyone has any ideas.
Also i have bought components and boards to build 20 modules, But as above only got 13 out of the 20 working, What are other peoples success rate. Spent to much money to move over to V4 now. Bloody 1 module short, so annoyed. Thanks Andy
Thanks, I am going to try that too probably somewhere this week.
Made a little progress in building some modules though 
Hello new to this forum hi
Really interested in bms solar, electronics microproceasors ect. I would like to build this bms could someone show me where the latest board is so i can buy it as i have many 18650s that need a home i have been trying to build a battery packs.
I have been a pcb deaigner could help in future with new designs if needed and help with design or hardware ect.
Am an expert in design spark, and protel, pcb packages Dos version, im old, could help with pcb advice ect.
Is now a final fully working design?
Or is there some of the latest boards for sale?
Wonder if someone could send a pm to
Chitu_Mihai-Georgehanks asmi am unable he has some boards for sale
Im so excited i wont be able to sleep tonight
Thank you
Hello david, i am new to this board, interested in your bms, wonder if you have any spare boards for sale thanks jon
It’s all Stuart Pittaway’s design. But I suggest you take a look at the most recent version.
https://github.com/stuartpittaway/diyBMSv4
Yes i have some more (~20 to spare). They are version v3.0, if you are happy with them i can send some.
This is the older design - take at look at V4 over here…
Hi @Andy do you get a voltage reading on the test point between that and cell negative? It should be about half the cell voltage.
Its strange that you are getting zero reading for both temperature and voltage - are the calibration values correct (if they are zero it would do this)
Does the web interface show the other voltages correctly?
Helllo diybms
Thank you, is this version 4 board