So I just finished my CS6, got the 2axis working etc. Tested it out pre gimbal and I had solid 20 minute flight times no payload. I go to test today with a battery, 70d and 10-22 EF-s (total payload around 2.7lbs). My Quadropower 6200 4's hit Undervoltage in about 1 minute of flight. My old MK frame would fly the same thing for 10 minutes easy. All I can think is my batteries are damaged. They go from 16.8 to 15.4 in the first 20 seconds. Same goes for gimbal, no camera. MK3638 motors 2.0 BL's 2.5 fc GPS/Navi. Using 14x4.7 props.
Do you have a GPX file that you can post, Ryan? What current draw are you seeing on the battery in that first 20 seconds of flight? It's not unusual to see the voltage sag quite a lot under load. You might want to check this document: http://rathergoodguides.com/document-guides/rgg-to-comparing-certain.pdf Andy.
Andy, Ill post them in a minute. The thing that weirds me out is no gimbal the thing will just sit for 20 minutes before it hits UV. Avg draw on the MC32 in hover was around 32-35 and liftoff was around 30.
That is odd. What's the history of the Lipo's? How long have you had them? At what voltage were they stored? How many charge/discharge cycles have they gone through? Andy.
Bought them new in feb 2014, Around 40 cycles at the moment (give or take 2). They are never stored for more then a day at full charge and usually around 14.8v when not in use. GPX files from the flights tonight. They may have got a bit hot while traveling, as I drive windows down all the time but it does not make sense as my 6s for the Octo are just fine (just tested it with the SAME setup and shot the sunset for 12.5min) and travel in the same case. One was involved in a crash, but the crash was just a broken landing gear/prop. I just balanced them all as one was sitting 3.84 while the other cells were 4.0. First 4 are under load, last two are no load.
Ryan: Here are the summaries -- it looks like the batteries are not starting out at fully charged voltages. If you have recently charged them, then they are defective, I'm afraid. Andy. NOTE: I edited this posting so it will not agree with any emailed versions of the posting. 14071600: Voltage : min. 13.6, max. 15 V << Looks like the battery was not fully charged. Current : 0.5 25 61.2 A Wattage : 8 358 832.61 W Capacity: 1102 mAh 14071601: Voltage : min. 14.5, max. 15.8 V << Looks like the battery was not fully charged. Current : 0.5 43 62.9 A Wattage : 8 652 912.05 W Capacity: 1682 mAh 14071602: Voltage : min. 14.4, max. 15.5 V << Looks like the battery was not fully charged. Current : 0.5 29 57.1 A Wattage : 8 432 826.5 W Capacity: 2019 mAh 14071603: Voltage : min. 14.4, max. 16.6 V << Battery may be defective -- initial voltage is a little low, but... Current : 0.5 45 57.1 A Wattage : 8 693 885.05 W Capacity: 2301 mAh 14071604: Voltage : min. 14.3, max. 16 V << Battery may be defective -- initial voltage is a little low, but... Current : 0.5 33 42.7 A Wattage : 8 502 610.61 W Capacity: 2892 mAh 14071605: Voltage : min. 14.4, max. 15.1 V << Looks like the battery was not fully charged. Current : 0.5 32 40 A Wattage : 8 477 600 W Capacity: 2721 mAh 14071606: Voltage : min. 14.3, max. 16 V << Battery may be defective -- initial voltage is a little low, but... Current : 0.5 33 42.7 A Wattage : 8 502 610.61 W Capacity: 2892 mAh
I know the first one the battery was not full due to using it to config the Gimbal. The other ones were full charge before flight. 16.8v. Ill do one more test tonight (love the streetlights here in Reno, we just got high intensity LED's)! Great battery doc btw=). I think I have a better idea of what is going on with these guys now. Looks like they are all defective =/
Well, after a full balance, and setting my UV properly. I just got a 10 minute flight on the one I thought to be the worst.
It's not unusual to see voltages like those in a GPX file. My style of flying is that I usually "punch it" on initial takeoff, and the way GPX recording works, the first samples aren't taken until the throttles above a certain value. And in my case, the copter's ascending at a good clip. And if you're flying 4S Lipos, your low voltage warning should be around 14.5 or so.
Yup, my UV was set a bit high. I think once I can find a build I like based around the new BL3.0s that will be the way to go. I am going to be cutting my payload in half, from 1100g (70d+10-22) to 510g (A7r + 35)
As I recall the MK source code the log file starts when the throttle hits 40% -- although it's not clear how that percentage is calculated. Steve: do you really see max voltages of only 15.1 volts on 4S? Andy.
Andy, I have seen that on 6s's under heavy load (red epic) with my CS8HL on occasion. I did 3 more flights under load today and got 6 minute flights on all 3 with the 70D. Did one flight with a 5dII and the Black Magic pocket each as well and got about 5:30 on the MkII (IR camera) and almost close to 7:30 on the pocket (350g)
Andy, it's been a while since I've flown a 4S system, but if I recall, I did occasionally see the voltage sag at takeoff (especially with a single battery), although generally to the mid-high 15s. I'd be alarmed if it went as low as 15.1V. That's one of the reasons I went to dual batteries on my octos.
On a 6S, Ryan? Wow. You mean the voltage for a fully charged 6S sagged from 25.2 volts to 15.1? That's a dead battery -- at 15.1 each cell would be down to 2.51 volts. Andy.