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Lipo over drain limitation?


Elite member
How do you keep from over draining a lipo? I am thinking through a normal wiring up -> lipo -> ESC -> radio receiver. Receiver gets a regulated voltage, so can't monitor the battery, so that leaves the ESC and or the lipo itself. Do they normally have some sort of over drain projection in them? or do you have to just guess?


Legendary member
1.use clock time , check your battery voltage after a flight, and calculate how long you can fly.
2. Its a lot of cheap soundalarms out there...
3... and telemetry modules to give you exact plane voltage on transmitter. (some can also give it approx. without a extra module)


Faster than a speeding face plant!
Most ESCs will slow down when your lipo hits a certain voltage. You will notice that the throttle does less.

Lipo alarms are great when you can hear them. They tend to be loud so you can fly around a bit but you have to learn the range.

Telemetry reports back to your ground station or remote. My Taranis tells me in English when I am running low on voltage. You can also put a voltage telemetry monitor on an OSD if you fly FPV. Voltage and current can be presented right in the HUD.

Timers also work well. You have to learn how long to set the timer for. My Taranis alerts me when I have been flying for x amount of time per model. I have one model that alerts at 3 minutes (4" Alien quad) and another that alerts at 19 minutes (Tiny Trainer).

Of all the solutions, the alarm @LitterBug linked to is the simplest and my first choice for a new pilot.


Elite member
I use a timer on the transmitter. When you start get airborne, fly for 3 mins then land and test the lipo with a battery meter. See what the V per cell is. Fly another 2 mins and repeat. You want to land at 3.6v per cell. I usually start my approach on the 30 sec count on my timer, then you have some extra fuel in the tank.
ESC’s for fixed wing do have some protection for the battery, remember when it’s cold out the battery will go flat faster. I drop my timer a bit to account for that. Most FT designs will give you 5-10 mins flying time.