I’m not sure if it is a bug/glitch or this is the way it’s supposed to work but here is my problem:
I recently started using 3DR power module with my APM 2.5 . Done the Voltage / Ampere calibration to the highest standards i could manage.
Ampere reading is always dead accurate. Down to the .01 . Voltage reading looks fine while on the ground. When I check it with a multimeter, it reads 12,58 and MP shows 12,58.
Problem is; as soon as there is load on battery for more then 1 amps, APMs voltage measurement goes crazy. With a fully charged 3S battery; my OSD sometimes drops as low as 11.3. It quickly climbs back up, but looking down to your battery voltage 5 minutes in flight and seeing 10V never stops giving me hearth attacks.
I thought that maybe it’s impossible to get an accurate voltage reading while battery is under load, but my 60 cents lipo low voltage alarms never seems to have a problem with reading the correct voltage.
So my question is, is there a way to make APM show the voltage as i see it on my lipo alarm(where it starts to beep as soon as i hit 10.6V). If there isn’t what’s the ideal voltage(as measured by APM) to land and what’s the voltage reading i’d get just before my quad tumbles out of the sky?
[mf]Copter/3.2[/mf]
[wf]Copter/3.2[/wf]
First of all, I don’t see what this has to do with the copter software. Correct me if I’m wrong, but I also doubt that you fly 3.2. At least you shouldn’t fly it.
Finally, about your problem… It is normal that the voltage of a LiPo battery sags under load. If it sags a lot, you either have a broken or bad quality battery or the battery’s C-rating is insufficient for the consumption of your copter.
[quote=“StefanG”][mf]Copter/3.2[/mf]
[wf]Copter/3.2[/wf]
First of all, I don’t see what this has to do with the copter software. Correct me if I’m wrong, but I also doubt that you fly 3.2. At least you shouldn’t fly it.
Finally, about your problem… It is normal that the voltage of a LiPo battery sags under load. If it sags a lot, you either have a broken or bad quality battery or the battery’s C-rating is insufficient for the consumption of your copter.[/quote]
Sorry for posting it in the wrong section. And yes now that i’ve checked it, i’m using the general release version. Not 3.2.
I’ve checked it with 4 different lipos(one of them 5ah 40C and my quad only pulls 30amps maximum). They are not the problem.
I also thought the sagging was caused by voltage draw, but then my question is, how does voltage alarms manage to get such accurate reading while under load?
[ul]I go under my quad while it’s hovering and read the display of alarm. It shows 11.8V.
I check the OSD and Mission Planner. It fluctuates between 10.5V and 12V.
I immediately land the quad and check the voltage with multimeter and it’s 11.8[/ul]
I wonder if voltage alarms take multiple measurements in 3 seconds it takes to cycle thru all the cells and then shows the average?
The voltage falls from 12.6 to 11.9 as soon as it launches(that’s the sag you are talking about). But after the take off, It acts normally. That is what i’m trying to achieve.