I am doing some testing on my machine and have a few questions regarding heat issues. Ive searched but cant seem to find anyone talking about heat and this particular motor. My question is this: are these motors prone to running hot? I wish I were able to give an exact amount but I need to buy a temp gun. Outside of that... I am used to my motors running extremely cool to the touch on my quad. I flew my CS6 yesterday with a full load-3 axis radian gimbal, 5DM3, 35 f/2 with video transmit and dual 6s 5200mAh batteries for power. After a 5 min flight, I wanted to check all the connections, ESCs, etc. One thing I noticed, the motor housings were hot to the touch. Much hotter than I am used to on my quad. I was able to hold my finger on the housing (maybe 2 secs) but have no idea what the actual number is. This is a new set up and I am just trying to establish a baseline so I can know what to expect. Right now, my concern is that if it's this hot after one 5 min flight, what will it be like when I start to run back to back flights with no downtime to help with the heat. My first thought is these motors just run hotter than I am used to. Is anyone running with these motors? What is your experience with housing temps? General ideas of what I can expect?
Chris, what was your all up weight, props, what was the outside temp, were you hovering or in moving flight? You may want to chart it in ecalc. I did a 12kg 6s 4014-9 with 14x4.7 and while it wouldn't take off (99% throttle with that load) it said the motors should be about 70c.
Oh yeah... sorry Gary. Here's a bit more info: all up weight is close to 9 pounds, outside temp was 88 degrees and my flight was mostly hovering but not completely still. I did move it around, just not aggressive. Also, I'm using the T-motor CF 15in props.
So ecalc says that the motors should be about 58C. So that would be be warm to the touch and likely you wouldn't be able to touch it for very long. High ambient, high relative humidity all contribute to density altitude. I don't see any data on max temps for the motors but ecalc generally gives a warning for motor temps at 80C. Best solution, breakdown and buy an IR thermometer. They not all that expensive and playing with the laser beam is a lot of fun on those days you can't fly. Did you know that a dog's exterior nose temp is 23.2C?
Yes. Agree that I just need to go and buy one, especially for this stage of testing. So from your observations, it seems that the motors are about where they should be. The only temp data I could find was on the T-motor site. The chart had a listing of prop sizes, voltages and other data. The highest temp I saw was 56C for the 17x5 CF at 22.2 volts. Always nice to have a bag full of toys while waiting around on set!
Last on the list says 63C. The first list is for the 4014-11. So sounds like the 80C max might be a good limit. And you can use it the temp unit as a laser pointer when you are teaching the newbies on set. Just has lots of uses. Check the temps on one of the big 24K Fresnels. Now that might actually be warm, hot, blistering...
OK... IR temp gun. Check. Motor 6 casing temp 38C after flight. Check. Motor 6 ESC temp 31C after flight. Check. Checking these temps on the ground after a crash. Check. Yep. A crash. As far as I can recreate in my mind, here's what happened, I think... Keeping the craft close to be but moving around, I wanted to run the batts down to 19.4 volts. I was at 8 mins of flight time and last I checked, the TX showed 19.7. I was returning from flying a bit higher and further out so was lowering altitude and bringing it closer to me where I would hover until I hit 19.4 on the TX and then set it down. As it was getting close to me, I had a low voltage warning, glanced at the TX to see what it was (noted that it was 18.8) but was also lowering the throttle to get it close to the ground and land immediately. The time frame for this next part was maybe 3 secs but hard to tell with no real frame of reference. Around three feet above the ground, it started to flip but slowly. I remained calm and as it was approaching the ground, hit the kill command to at least stop the rotors from spinning. No broken props. All seems to be OK. I did break the GPS pole (I'm using a WK-M) but other than that, no visible damage. I will check the props to see if they are still balanced but visually, they look OK. I know I'm lucky as the only broken part is a piece of fiberglass but I'm mad! I checked all the connections and all seem fine. Nothing is melted. No burt smell. But here is something curious... fresh charged battery and all cells were balanced-4.19x x~4-8. Actually this battery only has about 5 flights on it! It's on the charger now and I notice that the cells are way out of whack: 1-3.378 2-3.107 (!) 3-3.327 4-3.362 5-3.406 6-3.402 Any thoughts? Is this battery related? I am hooking it up to the WK-M to see if I had the low voltage alarm set. Maybe it was going to land itself? But why would it list to starboard? Confused and mad...
Well the temps sound ok. Sorry to hear about the crash. I don't think that the WKM has any logging functions. Taking the battery to 19.4 volts with no load is pretty darn low. I generally try to land when the load voltage gets to 3.6 volts per cell, so 21.6 on the 6S. For some that may be a bit conservative but I like safe. Guidance I have seen is a minimum of 3.4v per cell. After that likely to have some battery damage. So looks like the battery perhaps had a week cell and under load you were less, perhaps a whole lot less, than 3.4v. At 3 volts the battery is empty and probably toast. Load vs no load voltage difference on my copter are usually about .4-.5 volts. See what happens after the recharge, whether the cells balance. I also keep a charging log for all batteries. One of the data points is cell gap voltage. Good to be able to see if something is starting to go amiss. Generally my deltas are .004 volts as reported by the Hyperion.
Thanks for that Gary. I agree. Unfortunately I was taking advice from someone without doing my due diligence to further validate. That's exactly where I took it yesterday during my testing, actually I landed at 21.7 and this particular battery took 3115 mAh so I thought I was right on the money. I was misinformed that I could take the batteries down a little further so I was testing to see. If I would have done the math (DUH!) I would have realized that I was right where I should be. Regardless, it seems to be a battery issue. Everything else checks out and I am glad that at least I was returning to my LZ. 20 more secs and it would have come down hard on some concrete, wasting my machine and my 5D!