Copter enters FAILSAFE_BATT-1 mode with allmost full battery

I am new at building copters, built 2 sofar, the last one is a Tarot fy680 with 6 Quanum MT Series 4108 475KV motors and a multistar 10000 mah 10c lipo and a Storm32 3d gimbal.

After some great flights I noticed that the copter entered failsafe unexpectedy after about 7 minutes. After that Missionplanner kept complaining about low battery with a 99 percent full battery.

Some days later I tried a new flight, it took only a minute before the Pixhawk entered failsafe,

I do not understand this, the voltage is above the treshold for entering failsafe. This occurs even when I swap power module or Pixhawk for another one.

The logging files are here:

Can anybody please tell me what I am doing wrong?

Looking at the log, you have battery failsafe voltage set at 13.8v and the PH dutifully enters failsafe at 13.8v.

CURR/Volt in the logs.

Your starting voltage is 16.4v indicating a 4S pack, with a large voltage drop under load to 14.4v

Your failsafe voltage at 3.45v/cell is a bit high for such a soft battery considering your only drawing about 24A.

If that are the green Multistar batteries, run…I’ve had one and they sag terribly under load.

Thank you for your reply, I have lowered the failsafe voltage to 13,5 volts. Still I get warnings in mission planner, although not in QgroundControl.

Yes it is green, cannot deny it :disappointed: I do not know if it causes the problem, I guess the only way is to buy another brand or type. Can you suggest one for me please?

I have four Turnigy Nano Tech 8000mah 6S batteries that have serviced me well in the last year. I also just bought a Floureon 8000mah 6S but haven’t used it yet. My brother has a monster 4S Floureon and he likes it.

Also, try and stay away from batteries lower than 20C.