5 ms·
> The voltage is a mess on LFP That's a weird statement. The voltage curve for LFP [0] is just a lot flatter. That's nice for your electronics, but makes it ha
by andruby 2y ago
> The voltage is a mess on LFP
That's a weird statement. The voltage curve for LFP [0] is just a lot flatter. That's nice for your electronics, but makes it hard to estimate state of charge based on the voltage alone. So the BMS needs to keep track of total energy used to calculate state-of-charge.
[0] https://www.jackery.com/blogs/knowledge/ultimate-guide-to-lifepo4-voltage-chart https://www.jackery.com/blogs/knowledge/ultimate-guide-to-li...
- Filligree 2y agoExcellent link, thank you!
- speedgoose 2y agoTrue, it’s very flat. And If you add some major temperature changes over many days and a descent amount of non full charging cycles, it’s more challenging. Maybe I wasn’t told it was a mess, but it’s how I remembered it.
- Kirby64 2y agoThe problem is that total energy used is never fully accurate so coulomb counting can only be so good. Top and bottom balancing is needed to reset the algorithms, otherwise state of charge is largely a guess especially over time.