Phantom fc40 problem

fender37 · Dec 6, 2015

Hi All New to the forum
I have a phantom fc40 the problem is I have tried 4 new 2200 mA 3s lipo batteries and if the phantom
is running in idle mode the led as normal flashes green on/off and so on. As soon as I throttle to about
3/4 to full throttle the low battery red flashing led kicks in to warn low battery the props then speed up on there own then slow down, when I return the throttle stick to the centre position the led still flashes red.
I have tested the battery when this happens and the voltage show 12.45 volts @ 85% full
I have calibrated the battery in the nazm assist software but still have the same problem.
the setting are 1st level protection
no load 11.30v .....loss0.60v.........loaded 10.70v
2nd level protection 11.20v.......loss 0.60v........loaded 10.60v
I wonder is the naza-m unit in the phantom receiving these setting?
or is there a way of sending this data to the phantom
I have it connected to the software and the software is seeing the phantom ok
any help on this would be appreciated
thanks ian

discv · Dec 6, 2015

Very odd! The voltage levels you see in the assistant are from the Naza- so, yes, the settings are 'received'.
Had it been just one battery- I would have suspected it- but 4.

My instinct is something wrong with the electrical path from the battery. Faulty XT plug/s, solder joint gone high resistance etc etc. The motor speed varying confirms my instinct

fender37 · Dec 6, 2015

hi checked the connectors they are ok also tried the stock battery that came with the phantom full
charge that did the same thing I am stumped as to what it is causing the fault
if I switch of the battery protection then this does not happen as expected. I am holding onto the phantom when testing it would that make a difference?
so the readings are from the nazm unit and not whats set on the software
the software is ver 2.20
here is a copy of the version numbers in the phantom

discv · Dec 6, 2015

Has it ever worked OK? With regard to connection issues you need to pop the lid and double check all connections.

Varying motor speeds could be caused by hand holding- but it does not explain the low battery warning.
I'm still pretty sure you have a bad connection somewhere. Turning off 'low voltage' warning is masking the problem.

There are no issues with your firmware/software versions.

fender37 · Dec 6, 2015

hi thanks for your replies
yes had the top off all the wires are ok nothing loose or pulled out
I bought it from a guy who said it had been flown only 0nce (I should of asked to see it flying)
it was as new condition not a mark on it.
a friend came with me after buying it (he also has a phantom fc40) to test fly it and at the time it was flashing green led = gps mode
and one red led = the amount of satellite's found my friend said that was ok we did a compass
calibration 360 etc and he took it off. it flew up to about 6/7 feet then took off like a wild mouse to the left
lost height hit the ground then took off again and then rolled on the ground and stopped
all that broke was the landing leg (now replaced) after that I connected to the software and checked all was ok and did an advanced imu calibration .
I don't know if this latest problem has had something to do with the fly away because I had never tried full throttle up untill now. or whether it was because my friend was to eager to try it out before only the green led only was flashing after initial start up. ie as he powered it up to gain height it may of gone into low battery mode.
I read that I have to take a voltage reading of the fully charged battery then do a calculation via the calculation tab in the software I was doing this but did not realize I have to enter the battery voltage in the 2nd box then press enter, I did not put the voltage of the battery in the 2nd box I was just saying calculate ie pressing the calculate tab and leaving it at that.
I will try again on another fully charged battery

thanks ian

discv · Dec 7, 2015

Makes a nice change- seeing someone tackling a problem with some thought!
When you have done entering your low voltage settings- come out of the assistant, then go back in and check the settings are recorded.
IIRC you only need to input the no load voltages, the rest will self enter.

I'm beginning to think you may have a Naza FC problem, leaving only one option- a hard reset. But leave this as last ditch.
(My money is on that you have inherited this problem)

fender37 · Dec 7, 2015

yes an expensive mistake not seeing it work first (ahhhh) the guy seemed genuine but who knows?
anyway back to the problem in hand, I am waiting for the batteries to fully charge then will try again
I looked on the web and there was a video of rick from marionville models in Scotland talking about
the protection voltages his recommendation settings were
10.50v.....0.20v............10.30v in 1st warning
10.20v.....0.20v............10.00v in 2nd final warning and go into landing mode

is this right? as my settings showed a lot higher than this as shown in the previous posts
thanks again Ian

discv · Dec 7, 2015

Yes, that outfit in Scotland turns out reliable videos. Though his settings are about as low as you would want to go.
( I think he has one on the Naza reset- but we don't want to go there yet! )

But your issues puzzle me the more I think about it. I've yet to tie up the connection between apparent low voltage and erratic motor behaviour.
I'm wondering if there is a faulty motor/ESC (on the left- since it dived that way) that is causing a voltage drop- making the Naza get twitchy.

My thoughts include fixing the craft to a bench, disable low voltage protection, fit a Lipo voltage buzzer, and see what occurs.

fender37 · Dec 7, 2015

hi again
sorry I may of feed some wrong info here regards motors speed.
what I should of said it when the red leds start flashing (low battery warning) the motors speed up
with out any throttle input to a high rpm, they then slow down after a few seconds around (10/15 secs).then after the props slow down
the throttle stick on the transmitter has little effect when pushing it to the top (full throttle) ie does not speed the motors up to full rpm, (the motors only speed up a small amount)
I have spoken to rick today he says the setting were for another model and to leave the fc40 as per the factory setting regards voltages (I think they are a bit high). He also said if I am holding onto the fc40 whilst putting it into full
power may be causing a large load drain on the battery as the quad motors and props are under load
because of holding the fc 40 back from flying as it would under normal use(I suppose doing this is like adding a lot of weight to the fc40 holding it back) I was holding onto the fc40 by hand when it was powered to full throttle, this is when I got the flashing red leds but I would of thought that by reducing
the throttle power out put the red led flashing would stop and flash as normal, unless it has pulled to much load and gone into landing mode. (and the led stays flashing red) but the thing that puzzles me is the batteries read 60/70% full when testing them on removal from the fc40
hope this make sense?
thanks ian

discv · Dec 7, 2015

A lot of info in one post- and the sentences have come out spaced funny- making it all hard to grasp. With the greatest of respect!

So from the top; I fail to understand why the low battery LED would cause any variation in motor speed.

I agree that the default FC40 voltage settings would be a better option, rather than the low numbers Rick gave for another model.

What are you using to charge your batteries? And where does the 60/70% come into the equation?

Edit- ah I see now- when the battery is removed. 60/70% remaining should not have brought on the warning LEDs

fender37 · Dec 7, 2015

1......I use a jp lipro quad 6 charger it can charge 1 or 4 lipo's at a time I charge the batteries at 2200 mA
they took ages to charge to full capacity.

2 when the led goes flashing red the motors speed up then slow down without any intervention from me

3 with having that amount left in the batteries should the voltages in the software be changed?
ie protection is kicking in to soon.. or is it as rick says the problem is being caused by me holding onto the quad when on full power and putting a heavy load on the system.

4 is the receiver/nazm unit corrupted in some way.
I am completely lost as what is causing this and don't want to fly it in case it causes some danger
I have no confidence in it at all.
I fly turbine jets with more high tech stuff in them and are a lot less hassle

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I am beginning to suspect the batteries as all 4 batteries have a different run times for example
These readings were taken after the red led battery low warnings
1) 1st battery tried was a fully charged stock phantom battery holding onto the quad and different
prop speeds (as in all 4 tests) it lasted 5/6 mins the readings when removed was 14% left in the battery

2) 2nd battery was a Floureon lipo 25c rating that lasted 2 mins before the red warning led flashed
this was also fully charged it read when removed from quad 60% left

3) the third battery was a dynamic lipo 30c rating lasted 3 mins before red warning led flashed
again fully charged showed 45% left when removed from the quad

4) 4th battery was a turnigy lipo 10-40c rating this lasted 1 minute before the red warning led flashing after removing it read 65% left
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all batteries were fully charged and balanced (although I have Had these batteries from new they are about 11 months old and never been used and stored at the correct voltage)
has anyone tried the 4000 multistar battery from hobbyking or are they crap before I spend any more hard earned cash? .just thought it might be worth trying another battery
thanks ian

ps I read this on your forum site
......................................................
As far as the issues of the motors seeming to have a mind of their own, well they do, it's called NAZA.
When you start the motors, the Phantom expects to fly. If you add throttle, it will do it's best to climb.
That means the FC ( Flight Controller = NAZA Module) will continue increasing RPM until the Phantom climbs. It's NOT like the accelerator on a car.

discv · Dec 8, 2015

fender37 said:
1......I use a jp lipro quad 6 charger it can charge 1 or 4 lipo's at a time I charge the batteries at 2200 mA
they took ages to charge to full capacity. What output current is the charger set at?

2 when the led goes flashing red the motors speed up then slow down without any intervention from me Makes no sense at the moment

3 with having that amount left in the batteries should the voltages in the software be changed?
ie protection is kicking in to soon.. or is it as rick says the problem is being caused by me holding onto the quad when on full power and putting a heavy load on the system.
I would leave settings as they are- for now

4 is the receiver/nazm unit corrupted in some way. Not the receiver- but Naza M maybe
I am completely lost as what is causing this and don't want to fly it in case it causes some danger
I have no confidence in it at all.
I fly turbine jets with more high tech stuff in them and are a lot less hassle
---------------------------------------------------------------------------------------------------------------------------
I am beginning to suspect the batteries as all 4 batteries have a different run times for example
These readings were taken after the red led battery low warnings
1) 1st battery tried was a fully charged stock phantom battery holding onto the quad and different
prop speeds (as in all 4 tests) it lasted 5/6 mins the readings when removed was 14% left in the battery

2) 2nd battery was a Floureon lipo 25c rating that lasted 2 mins before the red warning led flashed
this was also fully charged it read when removed from quad 60% left

3) the third battery was a dynamic lipo 30c rating lasted 3 mins before red warning led flashed
again fully charged showed 45% left when removed from the quad

4) 4th battery was a turnigy lipo 10-40c rating this lasted 1 minute before the red warning led flashing after removing it read 65% left
I'd be amazed if all 4 batteries were dud.. That said, these numbers don't add up! The remaining capacity is a calculation from the charger- yes?
What we need to know is the true battery voltage at the point the first red LEDs show
--------------------------------------------------------------------------------------------------------------------------------
all batteries were fully charged and balanced (although I have Had these batteries from new they are about 11 months old and never been used and stored at the correct voltage)
has anyone tried the 4000 multistar battery from hobbyking or are they crap before I spend any more hard earned cash? .just thought it might be worth trying another battery
Keep your hand in pocket for the moment
thanks ian

ps I read this on your forum site True- but motor speed will not vary as you have described
......................................................
As far as the issues of the motors seeming to have a mind of their own, well they do, it's called NAZA.
When you start the motors, the Phantom expects to fly. If you add throttle, it will do it's best to climb.
That means the FC ( Flight Controller = NAZA Module) will continue increasing RPM until the Phantom climbs. It's NOT like the accelerator on a car.

There are simply too many variables here to know where to start. This is what I suggest.
Get hold of a couple of Lipo voltage buzzers- so they can be cross referenced to confirm accuracy.

Ensure your fully charged battery is showing 12.6v (3x 4.2v) Slightly less no problem.
Fix quad to work bench with buzzer attached. A stop watch would help sorting the results. Record everything as it happens
Run motors at a moderate speed to try and establish the true battery voltage at the point the first level LED kicks in.
Immediately after the test see if you can detect any heat build up on motor/s, ESC/s, XT plug and cable.

Maybe run the test a couple of times with different batteries. The results of these tests WILL hold the clue as to what is going on here- if we are bright enough to spot it!