Thank you Stuart for this great project. Just starting to put this together to control my Nissan Leaf battery pack.
What would be the max balancing capability over a day?
What might be a good alternative for the 475K resistor, RC0805FR-07475KL, which is OOS.
The capability depends on the battery voltage and the resistors in use. Typically Iâd say max is 20Ah over 24hrs - per module (approx 1A discharge)
Any resistor with the same specification will work - 0805 SMD size, 475K and 1% tollerance.
like this one⌠https://lcsc.com/product-detail/Chip-Resistor-Surface-Mount_BOURNS-CR0805-FX-4753ELF_C204531.html
Iâve updated the GITHUB version of the bill of materials today to update/replace the out of stock and discontinued products.
The only part missing is the LM4040B20 as LCSC donât sell that particular part.
Thanks Stuart for that updated BOM.
I am planning to use this BMS for my Nissan Leaf, and they are very high in capacity, where each cell can be 500Wh at 8.2 V module.
Any upgrade in resistor that can be made with your current PCB to improve on the balancing capability?
This BMS isnât suitable for over 4.5 volt per cell sorry!
I know. The Nissan Leaf cell module is a 2s 2p pouch module and a center tap makes the voltage less than 4.5.
My idea is to use two of your cell monitors per cell.
Any suggestions on upgrading the resistors?
Also, we need to purchase the parts you mentioned a few months back to build the controller isnât it?
I made some 3d printed parts to mount the Controller and BMSâ I thought they might be of use. The BMS has a battery clip (separately printable) to clip the BMS to the packs.
Itâs a work in progress, and will change.
Nice work @lanzecki
I donât think I would change the resistors, I suspect the leaf cells will be really well calibrated and in balance most of the time.
You will need to buy the few components for the controller - they are listed above.
Anybody want cheep components for this build here brought the more expensive items here just contact them they can get most things, including that voltage ref, you have to email them.
Use lcsc for resistors, capacitor ect, the cheaper items
Check out this recommended store on AliExpress. Find great products at low prices!
https://s.click.aliexpress.com/e/FGdPyAK8
Hi,
Can you upload this again? I am trying to make sure i order all the components.
Thanks
Same problem here. Those cables are described as âminiâ JST. In the end I just bought JST 2.0 sockets and cables from eBay. Those cables also didnât fit so I replaced the sockets with the ones that came with the cables. The hole pitch was slightly wider than the PCB holes so I had to pinch them slightly with pliers but they fitted ok in the end.
I bought : HavanaYZ 50 Sets Mini Micro JST 2.0 PH 2-Pin Connector Plug with Wires Cables 120MM 26AWG
To fit the connectors as per the BOM for LCSC.
I have my 2p7s pack ready and I was monitoring the cells for the last 2 days with only the load from the Wemos. Today I said to try a load on the pack to see how is behaving and after few seconds one of the cells disappeared from DIYBMS. The strange thing is that all 7 green status ledâs are blinking like before but I get only 6 reading bars in DIYBMS software.
I did reset de Wemos and disconnect and reconnect the balancing cable and is still the same. Any ideas whatâs not working properly here?
Update: I test the modules by putting the finger on the thermistors and the module that is not showing up in the software is number 7, I took the battery out I get a communication error of course and I put it back everything is blinking properly but the software is not showing the cell no. 7.
Second update: I powered the Wemos from a power bank and I get a error now, I think a kill module no. 7. How I was powering the Wemos during the test was from the most positive and most negative of the pack, around 28V through a 5V recom regulator that can have a max of 32V input.
Final update: I took out module 7 and is dead, the green led is always on, this is not normal because after I first flash the modules and connect a battery the led is flashing once and thatâs all. I think the 841 is dead.
Final conclusion - use a different power source for the Wemos.
hello
wonder if someone can help me please what sketch do i have to upload to my wemoss d1 mini?
Thats the ESPController sketch - but you need to follow the instructions here or use platformio to do this.
https://github.com/stuartpittaway/diyBMSv4/tree/master/ESPController
thank you, is it possible to use the aduino ide? i have a usb tiny programmer
im having truble trying to get the esp sketch into the wemos in the platform io
could spomeone please explain thanks
No Arduino IDE wont work. You can try following the second link I put above with instructions on installing without compiling the code.
Platformio is easy enough to use, it should auto detect all the devices on your machine and program it.
thanks stuart
I finally got my Raspberry running home assistant and I install InfluxDB and Grafana.
First I create in InfluxDB a database âDIYBMSâ and a âuserâ with password âtestâ and I give it all permissions.
Aftert that in DIYBMS in the integration tab I enable influx database: host server: 192.168.0.33 (ip of home assistant) / port: 8086 / database name: DIYBMS / username : user and password : test
In the Grafana I create my InfluxDB database âpowerwallâ with url://192.168.0.33:8086 / aceess :ver (default) - InfluxDB Details / Database: DIYBMS / user: user / password: test / HTTP method: get. Save and test was successful.
I crate a visualization but I donât get any data in.
What I did wrong?
This is from InfluxDB, I have only 6 cells left because yesterday I kill one module and Iâm getting something and the second image is from Grafana.
