Solved What is the low-voltage alarm set to on FT ESCs?

I was calibrating my control throws with a half-used battery and accidentally set off some sort of alarm. It was a single beep at roughly 1-sec intervals, and I assume it was a voltage alarm as my battery registered as "sub-25% charged" when I next charged it.

Do the FT ESC units have a low-voltage alarm? If so, what is the voltage at which it trips? And is there a secondary threshold at which they cut off power completely? Can't find a manual for these things anywhere.
 

Pieliker96

Elite member
It's probably something along the lines of an "ESC inactive" pulse to let you know that you've had it powered on for a good while without moving the throttle.
I don't know of any ESCs having a low voltage alarm, particularly the FT ones. I have experienced a few (particularly ESCs for RC cars) that'll cut power at low battery voltage, but that's less than desirable for model aeroplanes - I'd rather run my battery flat and make it down safely than have the model turn itself off midair.
 

chrisvdv

Active member
"I'd rather run my battery flat and make it down safely than have the model turn itself off midair."

That is whats called a brown out. And it happens a lot. As far as I know the FT ESC do not have a low batt warning.
 

Pieliker96

Elite member
"I'd rather run my battery flat and make it down safely than have the model turn itself off midair."

That is whats called a brown out. And it happens a lot. As far as I know the FT ESC do not have a low batt warning.
There's a brown out and then there's the ESC shutting itself off. A brownout occurs due to the onboard voltage regulators for the RX/Servos not being able to supply the demanded current, either from the load drawing more than the regulator's rated current (think running too many servos off a weak integrated BEC) or the input voltage to the regulator being insufficient, as in running the battery till it's dead.
What I've experienced in some car ESCs is a proper low voltage cutoff: the ESC turns off and doesn't recover as it would with a brownout. You have to unplug the battery and plug it back in in order to get the ESC to turn back on, whereas an ESC without LVC would power back on once the battery voltage rose to the operating threshold - typically immediately due to the sudden lack of load from the motor, which is why it's called a "brown"-out: It's temporary, not permanent.