dmwahl wrote:It's not necessarily cheaper, but standby power draw is substantially lower. Versions using the TL431 or similar parts will have 200-300uA of quiescent draw just due to the TL431 itself, plus resistor dividers to set cutoff points, and any other parts they may include. It's not a lot, but can easily add up to 0.5mA of constant draw from the cells which will draw around 1Ah every few months. The ATtiny one I put together was averaging around 8uA average draw, which would draw 1Ah every 15 years. That's lower than the normal self discharge of the cell itself.hillzofvalp wrote:I have made a SMD variant of this approach. I will share results soon. I'm not convinced that it is cheaper than analog methods utilizing comparators, however.
I'd love to see more details of your design as well, post a link to the thread here when you have it started. SMD is certainly the way to go if you don't mind dealing with the process, the BMS on my bike right now is 100% SMD.
Check out the TS882 and MCP6542 (300nA/500nA) and tell me what you think about using these for an analog bms.