It’s easy to check with my bench power supply. Mine only goes up to 18VDC (which is 5s-ish). So if I boot up my copter it believes it’s running at 5s. I then slowly dial down the voltage to 16.5VDC, I can observe the low voltage behavior.
I see where my error was .. I didn't have my desktop pwr supply set high enough to trigger things...as soon as I increased the voltage to 15v + the LED's lit up and when I cranked it down they started flashing right around 14.1v and the buzzer came on. Thanks for the help guys and yes Dave I should have said I had the wires connected to the A / - tabs as depicted on the wiki diagram not the + and - .. thanks!
Project update: Been working hard on getting my DYI brushless motor dialed in with the red camera on board. Here's a video I shot that shows the copter movement along and what the copter is doing as far as stability. Special thanks to Howard Dapp and Steve Maller for their tips and suggestions over the past couple months.
I have been flying this copter combo a lot. I probably have close to 40 flights on it and its all been very stable and solid. I just did a job with my 7D and the old Radian gimbal and I got 23.5 minutes out of a set of batteries. It's about as good as it gets and I can't complain one bit. I am about to build a 2nd copter so that I always have a backup. This one will be a X8 configuration with KDE 4014 motors and 18 inch props.
Few updates on this project. The flat 8 has been running now for well over 250 flights and responding good. Recently after I upgraded the power board to 1.06 firmware I noticed that the motors were spinning faster and working harder.I also saw on my GPX logs that my odd/even motor currents were drastically different. This problem caused me more time then I ever thought all because I simply was not looking close enough. Initially I looked at the motor alignments and they seemed to be ok, so I flew more and upgraded to 1.08 and then back to 1.04 and the problem was still there. I then rechecked the motor alignment with my bubble alignment tool I put on top of each motor. The bubble's indicated all were level. I then made sure the copter was completely level and rechecked, some were slightly left of center and some were slightly right of center. So I made every motor exactly the same and it fixed the problem. That was the first time I have ever saw that as I was never that critical about the motor angle before but apparently I now know that's the issue if it happens again. Copter and motors sound great and flew nice and smooth with the 1.08 upgrade now.
Dave your AUW is 26lbs if i remember right, what is your current flight time with 20% left on the batts
Thanks Dave I guess this is a good example that the MK Bl-3 puts some charge back in to the lipos, on this copter I am at 24 Lbs same motors, Batts, and props as Dave but I get 12-13m with 20% left
Recentl my flight times were decreasing because of the motor alignment issue but I've done several flights since its been fixed and I'm seeing about 15 minutes now. I also was able to get 20 minutes with the X8 flying the 5D mark III with a heavy lens.
Hello All Here's what I"m getting with each combo Flat 8 Tiger U5 motors All MK electronics with active breaking on 16" inch props - 520mm booms 2 - 10,000 mah QC batteries Flight time with Red and brusless motor gimbal I see about 15-16 minutes flight time Flight time with Canon 5D Mark II with radian gimbal I see about 22-23 minutes flight time X8 KDE 4014 motors All MK electronics with active breaking on 18" inch props - 500 mm booms 2 - 10,000 mah QC batteries Flight time with Red and brushless motor gimbal I see about 12-13 minutes flight time Flight time with Canon 5D mark II with radian gimbal I see 19-20 minutes flight time
Doesn't DJI have "active breaking" as a trademark? (Oops...had to edit that to get the spelling right!) Andy.
Thanks Dave, once your KDE motors are updated with the shaft 'fix' could you please post photos showing this update? I'm still interested on these motors.
Hi Andy, one of my copters has a DJI A2 its performing very nice as far as I know it doesn't have active breaking I wish it did, i think I get a little less time in the air than a equivalent components copter but with MK Bl-3