Hi guys I have had my 4th BL controller fail - this was one that was pre-soldered by quadrocopter so I know that it was perfect. I did 6 flights today, without any payload. On the 6th flight, motor 7 stopped and was trying to restart. The funny thing is that there are no error codes - only a restart error. Would someone mind looking at the gpx files and helping me understand what is going on. Can't seem to get around this problem. Parameters all look good too but maybe I don't know what to look out for. Thanks in advance Patrick
What's odd is that your motor #6 is pulling almost no current at all (1/3 of what one of the others is) which implies to me that there's something seriously out of balance on the copter. Did you have control over the copter? Or did the motor stop in flight? Here's the summary of the GPX file. As you can see, motor #6 is pulling very little power. Have you confirmed that the copter is balanced left to right and front to back? MK Version: FC HW:2.1 SW:0.88n + NC HW:2.0 SW:0.28m Flight date: 8/26/2013 5:17:36 PM Flight time: 5:17:36 PM - 5:22:58 PM (322 secs, 00:05:22) Batt. time : 484 secs, 00:08:04 Elevation(GPS) : 0 5.76 98.308 m (min/avg/max) Altitude(Barom.): -0.85 0.55 2.15 m Vertical speed : -26.98 0.03 24.91 m/s Max speed : 31.8 km/h Max target dist.: 0 m Sats : 7 10 12 Voltage : min. 14.5, max. 15.8 V Current : 5.9 31 67.5 A Wattage : 90 481 1032.75 W Capacity: 4311 mAh Motor1: 0.6 5.0 14.2 A Temp: 35 53 68 °C Motor2: 0.7 4.4 7.8 A Temp: 39 53 64 °C Motor3: 0.1 3.5 6.3 A Temp: 46 57 71 °C Motor4: 0.3 3.5 7.3 A Temp: 46 54 66 °C Motor5: 0.1 3.8 8.5 A Temp: 44 53 65 °C Motor6: 0.0 1.6 3.3 A Temp: 42 52 65 °C Motor7: 0.1 3.6 6.7 A Temp: 38 47 54 °C Motor8: 0.6 4.0 7.3 A Temp: 37 52 61 °C Magnet Field: 85 101 113 % (ok) Magnet Inclination: 42 47 62 deg No errors found
Hi Steve The copter is perfectly balanced. I have done a hang test and spent a lot of time getting it perfect. Flight was not a problem at all and control was normal. I'm not sure what else it could be. Maybe I will replace the motor on #6 and see if it improves. Thanks for your advice though. Number 6 didn't stop at all. It was only number 7 that stopped after I had landed, then struggled to start up again prior to the next take off. Very strange indeed.
Steve: I've seen that kind of problem before where a BL-Control under-reports the current. In this case (and the others), if you use the temperature range of BL Ctrl #6 as a proxy for the current, you can see that #6 is running as hot as the other motors and, most likely, the only reason it's running that hot is that it is drawing the same or similar amounts of current. Just a thought.... Given that Patrick's had several BL Control's fail -- in contrast to most of us who have not had one fail -- I suspect there is something wrong else where. The first thing I would check is the soldering on the PDB. Also are all the capacitors attached by goop or hot-glue to the PDB, or are there any issues there? Having one BL Ctrl fail is unusual, having four fail is obscene.... Andy.
Hi Andy I actually ordered a pre-assembled PDB with Bl Ctrlers to ensure that it wasn't just my soldering. I can definitely say that there must be something else wrong but figuring out what is the hard part. All attachments are by hot glue but I do not have cooling fins. I am about to order some and see if that helps my problem. What I can't understand is that the temperatures all seem to be ok across all motors and nothing really stands out. Can be very frustrating. I'm going to go back and re-balance everything (although I am sure it is perfectly balanced already) Is there a certain amount of time you should let the motors "rest" in between flights?
Hi Patrick: Based on what you're saying, I think it's something other than the temperatures of the BL-Ctrls. The Error 23 "Motor Restart" error you are reporting suggests that there is a problem with the motor wiring. You would see an Error 24 BL Limitiation" if a BL-Ctrl was drawing too much current or getting too hot. That suggests that there may be a loose connection, or a dry solder joint, on either the power distribution board, or the motor bullet connectors. I would examine the power distribution board under a magnifying glass and in good light -- there may be a whisker of wire and/or solder that's perhaps intermittently shorting out the MOSFETs on the PDB. Unfortunately, I've not had a chance to look at the GPX files themselves -- I don't have a PC available right now.....so please do confirm that you are indeed seeing an Error 23 Motor Restart. Hope this helps Andy.
Hi Andy Here is the error message: - max. FC I2C Errors: 0 - at least one error occurred! (3) - 1 Error(s): Motor restart Apart from that, there were no other errors - I am going to go over the PDB with a magnifying glass at some stage over the next few days. What I find strange is that the BL-Ctrl for Number 7 now has the solid RED and GREEN LED on. This is exactly what happened with my previous 3 failed Bl's too. What is strange is that I have been flying a lot over the past 2 months and it has been performing beautifully (with a full payload - 7d with 24-105mm Lens) and then as soon as I flew it without any load, this seems to happen. I have another PDB at home that I might rebuild with new Bl's and see if I can ensure there are no loose attachments or wires and see if that fixes the problem. Will also put the cooling fins on and monitor the difference. Cheers, Patrick
Yeap, I have that on my #7 right now. It's my original PDB board. In June I had a BL fail that I didn't have enough time to replace right away so I went to my back up PDB. My backup PDB showed #7 right in line with everything else. Then after my crash I went back to my original PDB and #7 is back to reporting low current. But the copter is in perfect balance and runs great.
As you say, BL Ctrl #7 is not a happy camper. The solid red is telling you "There has been an error. See if you can guess what it is." (One normally only sees that on Windows. ) It's a bit hard to imagine why flying "no load" would cause a problem, but I suppose stranger things have happened. The cooling fins will only cause a small decrease in temps -- it's airflow that does the most good. Please keep us posted with what you find so anyone else with the same problem knows the resolution. If you've not changed a BL-Ctrl before, do a Google search for: mikrokopter replacing bl-ctrlthere are a couple videos that look promising. Andy.
Given the data in your GPX files, I would not bother with the heat sinks. Your temperatures are well under anything alarming. I believe your problem(s) is (are) elsewhere.
Hey Andy and Steve So, today I just thought I would try a startup and see if anything had changed. The Bls were all green (8) when I connected the battery, the red LED had disappeared on #7, calibrate and start, no 7 motor tried to start but was just half spinning and surging. I replaced the motor with a new one and it ran perfectly. So, it seems my BL's that were turning red may not of in fact been failing - someone on one of the forums advised me that once you saw a solid red, the best bet was to replace it. I am doing some fault analysis to see where in the motor the problem could be and will let you know what I find. My first though is that it could be the motor leads where they bend down into the boom - I have a transport case with foam that pushes on the wires a tiny bit and maybe all the movement has caused a wire to separate. Will soon find out! Thanks for all your advice guys, glad I didnt replace the BL as I have done on 3 other occasions :/ I'm going to retest the old ones and see if they are ok now. Regards Pat
Well, I'm both glad and sad to be right regarding the motor wiring....that's an insidious little fault that has wasted a few hours of your time, I bet. Thanks for posting, though. Hopefully it will save more than one person a few hours! Andy.
This is why I can't wait to get rid of MK bls. Seperate ESC's seem to make the most sense. Just waiting for the ff synapse to hit the shelves.