Quote:
Originally Posted by notnodak
I just checked my firmware and it says that auto is 3.0/cell. I'll try the 3.3= 13.2v for the time being, unless my runtimes aren't great. What does it actually do when it's to low? Just stop, beep or stutter?
|
3.3v is good. If you set the cutoff too high, the worst that will happen is your runtime will be cut short.
Setting the right LVC point can take a little trial and error. Set it to a safe high value to start (like 3.5v as Freezebyte suggested) and run it. When the LVC kicks in, disconnect and let the pack rest for a few minutes. Hook it to the charger and see what the voltage is (not charging yet) of the depleted pack. You generally try to shoot for a resting voltage of 3.6-3.7v/cell unloaded. If the voltage is above that, you can decrease the LVC to 3.4v and repeat until you get the desired resting voltage. Having a resting voltage high isn't "bad", but you are losing runtime. If the voltage is still low (like 3.4v), then you need to increase the LVC. Chances are that if you have a 3.2-3.3v/cell cutoff set and the resting voltage is under 3.6v/cell, the pack is probably not adequate for the job and is working too hard. Also, a hot pack (over 120*F) means it is working too hard, and could mean the batteries are no suitable for the setup. Gearing down and programming the ESC with gentler settings (higher punch control) can help reduce current needs and be better for lesser cells.
Freeze, you are right that there are peak currents that may cause excessive voltage drop, but these packs are designed to handle bursts like that. The ESC does seem to absorb those peaks so it doesn't false trigger.
From what I've seen, when the MM/MMM nears the LVC point, you lose a lot of snap, but not sure if that's just the battery getting towards the end, or the cutoff kicking in. Within a minute or less of this, the ESC stops.