That is great news. Which Arduino are you using?
I have plans to mount the Arduino and voltage divider on some veroboard this weekend (I always have great plans for my weekends) and see if i can then print a case to hold it.
I am still working through how the final item will look. My voltage regulator has arrived so I will add that to my circuit and test. Once I have done that I can produce a drawing and parts list of my finished concept.Hi, nice project! I always wondered if an Arduino can be used as a bms and there it is! I would appreciate a step by step guide!
Hi fpvsteve,Depending on the manufacturer, the point of no return (=permanent loss of capacity) of a lipo cell is between 3.0 and 3.3V/cell.
If you trigger failsafe at 13.2V for the entire pack it’s almost guaranteed that one of the 4 cells will drift and go below critical voltage during RTH. Also 14V for the entire pack is too low. I would bet that this is the main cause for dead Solo batteries.
In my RC models and DIY drones I am using battery monitors to control each individual cell and to trigger action once one of the cells goes below 3.6V under load. That’s giving enough of an emergency reserve to return home or to land at a safe place and to keep your batteries alive for many years.
For Solo you can monitor the individual cell voltage in Solex but not trigger a failsafe action. It would be nice if you could add to your project!
Thanks hyoo,Hello. Here is eagle schematic and board/gerber file from your design. PCB size is 55x63mm.
But I used arduino pro mini instead because of size. It has not AREF pin. so I leave one pin with LM4040. it need to be jumped from pro mini. Just google it. You can find full information to do it.
There are anything to be corrected from files. let me know. I could correct.
I think you have almost finished this project. Hope i will make one for my solo(s!) soon.
That will be the ultimate goal. You can even get some of the PCB suppliers to assemble the board which for the surface mount components may be the way to go. The voltage regulator can be replaced by a surface mount one (RS Part number 885-5432) further reducing the space required.JLCPCB anyone?
[And I haven't forgotten your batt webbs. It's in my queue]
That will be the ultimate goal. You can even get some of the PCB suppliers to assemble the board which for the surface mount components may be the way to go. The voltage regulator can be replaced by a surface mount one (RS Part number 885-5432) further reducing the space required.
Using the Arduino Pro Mini will reduce the size required and if a programming header is added then that would make it simple to program with a USB to serial adapter. I think i will look at writing a calibration program that could be downloaded into the arduino first to work through a procedure to work out the Vref and voltage divider resistor factors. Once you have these factors you can add these to the SMBus code and download it.
I have had a though about the coms and could solder a plug directly to the 6 pins on the end of the pro mini so it wouldn't need to be on the circuit board. I have also just used a 6 pin dupont connector and held it at and angle to make a connection to these pins to program it in the past.Hello webbs,
You can connect directly normal(i guess) usb/ttl adapter to pro-mini's upper pin holes. VCC/TX/RX has no problem but different GND position. I personally used to bend GND pin of usb/ttl adapter and jump to pro-mini's. btw I corrected board to have header for usb/ttl adapter for convenience. It could be cut off. and changed connector for bat's balance connector.
The other version of board is dip sw pull-down resistors ver. It maybe live without these. but...
If you choose proper and smaller fancy^^ smd v regulator. It should be much better.
I used to order pcbs from JLCPCB. cheap reasonable quality and faster shipping at least to my country.
Regards
ps: AREF out of pro-mini (see below of this link: Arduino Pro Mini + MMA7361)
The total looks ok but the cells are very strange..... I didn't know you could see the cell info in solex, that will be great for testing.I am having trouble with the cell voltages that are being reported. They are all over the place and the total voltage doesn't match either. What could I be doing wrong. I have used 2 different arduino's and triple checked my wiring. Any thoughts?
Kind regards,
Perry
We use essential cookies to make this site work, and optional cookies to enhance your experience.