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LOW BATTERY RTL ADJUSMENT

Joined
Jul 23, 2017
Messages
40
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Age
48
Hello, is there a way to adjust the Low Battery RTL Landing function? 20% is too much. I need the extra 5% to 15% battery level to get the shots I need. Yes I can plan all I want 'till Sunday but in the end things happen and a few seconds here may not be a problem but a few more seconds there of something that I may see and didn't anticipate I need to get it in the current lighting, but the darn H PLUS comes abruptly begins the flight home at 20% and this action is jarring and is not cinematic. For me it would be much better if the RTL switch activated at 15% or even 10%. Yes, I understand about battery level and not flying to 0%. I don't do that, but I always immediately charge my batteries (after they cool to room temperature) to STORAGE level. So the batteries are never below 5% on any of my other drones for more than an hour.

It just would be nice to be able to adjust the Low Battery RTL level.

Thanks.
 
Unfortunately this is not adjustable on the H Plus. It will take better planning for battery changes to avoid having RTL kick in. It is possible to override the auto RTL from the battery warning, but it is not cinematic. To do this just quickly flip the mode switch from the mode you are in to another and back quickly. It should give you about 60 seconds each time.
 
1) Some technical background
----------------------------------------

The thresholds for battery-related actions are defined with following parameters:
BAT_CRIT_THR (FLOAT)Critical threshold
Comment: Sets the threshold when the battery will be reported as critically low. This has to be lower than the low threshold. This threshold commonly will trigger RTL.

Reboot required: true
0.05 > 0.25 (0.01)0.07norm
BAT_EMERGEN_THR (FLOAT)Emergency threshold
Comment: Sets the threshold when the battery will be reported as dangerously low. This has to be lower than the critical threshold. This threshold commonly will trigger landing.

Reboot required: true
0.03 > 0.1 (0.01)0.05norm
BAT_LOW_THR (FLOAT)Low threshold
Comment: Sets the threshold when the battery will be reported as low. This has to be higher than the critical threshold.

Reboot required: true
0.12 > 0.5 (0.01)0.15norm

What should happen is defined with parameter

COM_LOW_BAT_ACT (INT32)Battery failsafe mode
Comment: Action the system takes at critical battery. See also BAT_CRIT_THR and BAT_EMERGEN_THR for definition of battery states.
Values:
  • 0: Warning
  • 2: Land mode
  • 3: Return at critical level, land at emergency level

COM_LOW_BAT_ACT=3 should be there.

Parameter reference:



2) Typhoon H Plus
-------------------------
H Plus is based on PX4 Autopilot but customized for Yuneec needs. Most of the parameters are read-only due to security reasons. I don't know which one. Due to customized handling, changes in parameter may have unexpected effects. Whatever you do, do it on your own risk.

I do not have a H Plus (at least a working mainboard which would be enough to do testing). That's why I start here speculating. May be it is possible to access the some of the parameter with QGroundControl. However, reading the parameters is possible.

If you can access parameters with QGC, from my experiences with Typhoon H and PX4 firmware (aka Thunderbird) the Critical battery threshold should not be below 10% (=0.10) to have enough capacity for RTH. The minimum setting 5% is dangerous. Your idea with 15% sound reasonable.

Important remark: If you use QGC, never do a firmware update using QGroundControl. This may brick the H Plus.

br HE
 
The best approach is if this threshold is floating in relation to the distance from the home landing point. Also, 15% is enough power in a new battery and a crash power for the old battery.
 
Unfortunately this is not adjustable on the H Plus. It will take better planning for battery changes to avoid having RTL kick in. It is possible to override the auto RTL from the battery warning, but it is not cinematic. To do this just quickly flip the mode switch from the mode you are in to another and back quickly. It should give you about 60 seconds each time.
Thank you. I agree it isn't very cinematic and I have tried that "flip the mode switch" option. From my experience it seems that the H+ wants to re-initiate the RTL within about 20 seconds. I suspect this is due to current flight characteristics which is all the more reason I would like to have just one to 2 more minutes of flight.
 
1) Some technical background
----------------------------------------

The thresholds for battery-related actions are defined with following parameters:
BAT_CRIT_THR (FLOAT)Critical threshold
Comment: Sets the threshold when the battery will be reported as critically low. This has to be lower than the low threshold. This threshold commonly will trigger RTL.

Reboot required: true
0.05 > 0.25 (0.01)0.07norm
BAT_EMERGEN_THR (FLOAT)Emergency threshold
Comment: Sets the threshold when the battery will be reported as dangerously low. This has to be lower than the critical threshold. This threshold commonly will trigger landing.

Reboot required: true
0.03 > 0.1 (0.01)0.05norm
BAT_LOW_THR (FLOAT)Low threshold
Comment: Sets the threshold when the battery will be reported as low. This has to be higher than the critical threshold.

Reboot required: true
0.12 > 0.5 (0.01)0.15norm

What should happen is defined with parameter

COM_LOW_BAT_ACT (INT32)Battery failsafe mode
Comment: Action the system takes at critical battery. See also BAT_CRIT_THR and BAT_EMERGEN_THR for definition of battery states.
Values:
  • 0: Warning
  • 2: Land mode
  • 3: Return at critical level, land at emergency level

COM_LOW_BAT_ACT=3 should be there.

Parameter reference:



2) Typhoon H Plus
-------------------------
H Plus is based on PX4 Autopilot but customized for Yuneec needs. Most of the parameters are read-only due to security reasons. I don't know which one. Due to customized handling, changes in parameter may have unexpected effects. Whatever you do, do it on your own risk.

I do not have a H Plus (at least a working mainboard which would be enough to do testing). That's why I start here speculating. May be it is possible to access the some of the parameter with QGroundControl. However, reading the parameters is possible.

If you can access parameters with QGC, from my experiences with Typhoon H and PX4 firmware (aka Thunderbird) the Critical battery threshold should not be below 10% (=0.10) to have enough capacity for RTH. The minimum setting 5% is dangerous. Your idea with 15% sound reasonable.

Important remark: If you use QGC, never do a firmware update using QGroundControl. This may brick the H Plus.

br HE
Thank you for this information. It's too bad Yuneec didn't make the coding a bit more "OPEN" source. I understand the security but why use a PX4 then? Just go back to their proprietary.
I have QGC but I have never used it on anything other than some racing quads and Parrot drone products. I may give it a try but I am not sure I want the risk either. Thanks again for the information.
 
The best approach is if this threshold is floating in relation to the distance from the home landing point. Also, 15% is enough power in a new battery and a crash power for the old battery.
Agreed. Which is why I know not to ask for less than 15%. I usually am right over head or within about 100 feet when the first battery warning comes up. It is just my luck that during that last minute or two something interesting comes into view and I want to capture it but the TH+ starts its RTL maneuver and making my shot unusable or not good. If I could get an extra minute or so I would be good. Once I start the landing procedure I have personally committed and it doesn't matter anymore.

Anyway, thank you.
 

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