This is something that i always wanted to be able to track from my phone. Thanks for the doing the work and for making it available for everyone when it is ready. Kudos !
Aaaaaand⌠i blew my nano 
Trying to connect the VESC to the arduino, started getting parasite voltages and boom, goodbye nano.
Good thing is op-amps arrived and new nanos come on monday so i can start designing V2 which will isolate the balance lead inputs and prevent this from happening again.
All back to normal, and the new implementation with differential amplifiers works much much better. Still not perfect, but very good. Main problem with differential amplifiers is the common mode range, in the case of the LM324AN iis Vcc - 2, so when you get to the last cell of the battery, you need to use a voltage divider to get it into that range, and this adds an extra layer of error possibility. I believe opto isolators are the way to go. They have all the positive things of op-amps and none of the drawbacks (at least in this implementation)
It doesnât look pretty, but i cant be bothered to route a pcb until i have my final design.
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This was a nice project⌠to be honest, it looks like there are not that many cell meters on the market 
I never made a final version of this, just used the last prototype for a while but now im using pretty good bms so having this is not necesary anymore.
which one are u using?
Im planning on implementing bms for charge only, so I still need something for low charge monitoring for each cell⌠been looking and so far the best option seems to be IDST smart battery checker but im not sure yet if im ready (my friend actually) to invest 20usd to buy it⌠even if it is really good.
Then again there are these loud buzzer alarms but they dont seem reliable for me and once they start beeping they are super noisy and annoyingâŚ
Im using raphaelchangâs bms and will soon start using JTAGâs bms.
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Good choice. Then I totally understand why u said good bms
Hi, Aborn
Have a landwheel board and modifying it, It is not a terrible idea, To improve the skateboard with a power generator battery pack, for charging 10s 42.2v battery on the go. I was wondering if you knew how to connect bluetooth device to my phone or smart watch because while charging skateboard battery which is in my backpack it would be good to see the charging without having to stop to pull the battery out of the bag. You have a great project but could you simplify it, to monitor battery charge with bluetooth.
Good day, Great work.