red_z06
Elite Veteran
Location: Dumont, NJ
| The typical standard auto lipo cutoff is set somewhere around 3.0-3.1v for ESCs. This was based on yesterday's standard on safe lipo voltage of 3.0v per cell. Although the cell does not receive immidiate damage, it has been shown that repeated use to this voltage will shorten useful battery life.
I time all electric flights so there is 20% reserve in the pack when the alarm goes on for me to land. But, once in a while you either forget to set the time or simply blow through the timer and are met with the lipo cutoff of ESC. At this cutoff, the pack has much less than 10% reserve left and gets much hotter even for the same flying as the pack has to pump much more current to compensate for the dropping voltage.
I have been testing a safe cutoff voltage for ESCs (CC mainly due to adjustability). For heli setup, current sensitivity should be set to insensitive or disabled. I set the cutoff to 10v for 3s or 3.33v per cell. With this setting, with slow cutoff (current limit to maintain 10v under load), your 3s pack will see 10.8-10.9v when the cutoff occurrs. This is a much safer level for the pack leaving 15-20% reserve that you are looking for. Obviously, if you land before this occurrs, even better.
For most beginners practicing (except inverted), there is enough time for you to safely land when the safe cutoff starts to slow down the blades.
For other ESC's that do not have voltage selection, go with high cutoff. If the document does not specify what that voltage is, do a hover test until it kicks in and wait 5min or so for the pack to stablize then measure the pack voltage (no load). If it is 10.8 or above, you can fly until cutoff occurrs without worry.
What I also found is that, at higer cutoff voltage, due to 20% energy still in the pack, the amount of time you have to bring the heli in is much greater than for the lower cutoff.
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