June 4, 2018 at 12:35 pm #12399richard.joyParticipant
While flying the other day I received a low battery audio alarms shortly after taking off even with a fully charged battery. How does FlightDesk determine what constitutes low or critical battery levels and is that configurable ?.June 4, 2018 at 12:55 pm #12400Florent MartelKeymaster
The low and critical battery alarms are triggered when the cell voltage is below certain thresholds. These thresholds are configurable through the FlightDeck configuration screen which is accessible from any FlightDeck screen by pressing on MENU.
If you have a FrSky LiPo sensor (i.e., FLVSS or MLVSS) the cell voltage is the lowest cell voltage as reported by these sensors. Without a LiPo sensor, the cell voltage is an average based on the battery pack voltage as reported by ArduPilot, given an automatically detected number of cells during initialization, whereas cell voltage equals battery pack voltage divided by the detected number of cells. You can check how many cells have been detected by pressing ENT after init. FlightDeck will show the detected number of cells as “3S” for 3 cells, and so forth, directly to the right of the displayed cell voltage.
For best results, we always recommend starting, like you did, with a fully charged battery, not only because of the auto detection of the number of cells, but also because ArduPilot expects to start with a fully charged battery, and a number of indicators within ArduPilot (including battery failsafes) are based on the assumption that you’re starting with a fully charged battery.
We always recommend the use of an FLVSS or MLVSS sensor, which is a very easy way to find out whether a cell in a pack is failing…June 4, 2018 at 1:19 pm #12401richard.joyParticipant
Thanks for the quick reply. I checked the FD config and the low threshold is 3.6 v and the critical is 3.4 v so don’t understand why the battery would dip so low shortly after take off. I do have a FLVSS but it wasn’t fitted to my drone the other day so I’m going to test again with it installed.
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