Back in June I was designing ROSbot Dave’s safetyShutdown.py battery charge monitor and chose:
- WARNING: (Flash WiFi LED Orange) 10v
- SAFETY SHUTDOWN: 9.75v
- write session duration and final battery voltage to log
- initiate shutdown -h
I just ran an unprotected discharge to battery cutoff which confirms 10v warning flasher:
- starts 30 minutes before total battery exhaustion,
- ~15 minutes before chosen safety shutdown at 9.75v
Full Charge 12.5v (open circuit) to
Battery Protection Circuit Shutoff at 8.5v (under load)
This run was 2599mAh in 5.6 hours = 464mA average load
It shows I am shutting down at 5% remaining battery capacity.
This level of discharge might be stressing the battery cycle life - we’ll see. At this point the battery has about a 100 sessions of an average 1.3 hours each in 1.5 months. I don’t always charge it after a session though - only if the voltage is below about 10.5v will I put it to charge. Internet wisdom recommends Li-Ion batteries should not be “stored” fully charged or fully discharged. Dave is only “stored” 18 hours at a time, max.