Hello!
I built an octoquad with 8 motors (readytosky 2212 920kv) and have a 4s 5200mah battery. Im trying to autotune my copter but only a minute into the flight the low battery failsafe appears (RTL) looking at the power monitor graph, bin file attached in the drive ("Bad Battery Failsafe" - Google Drive)
the voltage drops like a rock but when it lands it goes back up again. Is this normal? how can I overcome this?
any comment is more than welcome, I hope you are having a great day
FYI: I have flown this drone without the battery monitoring and managed a 10min flight with the voltage no droping from 13v (I checked it when it landed)
13v on a 4S lipo is too low, especially for the recovered (after flight) voltage. If that’s the case the battery has been killed and has no capacity left.
As for this flight, the log only shows 800MAH drawn from the battery. (I’m assuming your current meter is calibrated, the current draw of ~20A looks reasonable but I can’t say for sure so I’m just trusting it) Given how the voltage is recovering, I suspect either the battery is worn out, or you are pulling more current than the C rating for the battery can reasonably tolerate. Note that C ratings published on the batteries are optimistic at best and outright lies at worst. That said, 20A isn’t unheard of so I would expect a good battery to hold on longer.
Try a different battery if you can, but I think this one is done.
I was suspecting poor connection due to soldering or too thin wires used.
But most probably this LiPo is just at the end of it’s life and has high internal resistance.
You’re right about a parallel battery, but it also increases the weight. This drone is looking kinda heavy since it’s hovering with very high PWM values. Try it with one battery just to see how it does. The current draw went up over 5 amps. Have you calibrated the current meter?
