Howdy... Still in my initial training days with my new C8 and this has me stumped... A nice easy flight today, not to heavy, just a handycam on board. Everything is fine, but as I come into land, Motor 4 shuts down! BL Overload? What on earth? I've uploaded the GPX File. I sure hope someone can help me figure out what happened. Managed to land it safely, as I was coming in to land anyways, but what was the problem? Thanks for any help you can offer... Ben
Looks like you had motor 4 go WAY overtemp... Flight time: 10:16:52 AM - 10:19:43 AM (171 secs, 00:02:51) Total: 371 secs, 00:06:11 Elevation(GPS) : 0 5.11 13.277 m Altitude(Barom.): -2.35 3.41 12.05 m Vertical speed : -1.53 0 1.7 m/s Max speed : 9.6 km/h Max target dist.: 0 m Sats: 10 12 13 (min/avg/max) Voltage: min. 14.6, max. 15.7 V Current: 5.4 47 62.3 A Wattage: 82 712 940.73 W Capacity: 4922 mAh Motor1: 0.4 6.5 8.7 A Temp: 38 71 83 °C Motor2: 0.7 6.4 12.6 A Temp: 43 76 87 °C Motor3: 0.5 6.5 8.7 A Temp: 37 57 67 °C Motor4: 0.0 5.1 11.1 A Temp: 35 67 147 °C Motor5: 0.5 6.3 11.9 A Temp: 35 51 57 °C Motor6: 0.7 5.7 11.2 A Temp: 34 49 55 °C Motor7: 0.6 5.9 8.3 A Temp: 36 54 61 °C Motor8: 0.0 2.9 4.2 A Temp: 38 59 71 °C Magnet Field: 99 101 105 % (ok) Magnet Inclination: 55 58 64 deg Errors / warnings: Error "Motor restart" (23) occured 7 times! Error "BL Limitation" (24) occured 9 times! FC-Flag "LowBat" (5) occured 1 times! Im trying to figure out why though.. looks like all the other numbers were ok? Josh
Howdy... So, I just did a quick on-ground test. No flight, so no log file, but almost immediately, Motor 4 was starting and stopping by itself. It would stop, then restart after a few seconds, then stop again. Saw some smoke coming from the PWD too... So, does this mean that motor 4 is fried? BL 4 is fried? Both? How and why could this happen? What should I do to rectify this? Thanks! Ben
I am guessing that is the case. 147*C is just under 300*F! They fail at 115*C. I am wondering what caused that. Are you using heat sinks? Josh
No... as you know, it's still nice and cool here in AZ. No heat sinks... So, what now? What do I replace? What was the cause? Is this a warranty issue? Best, Ben
Can you post a picture of BL4 how it sits currently with everything around it? Wondering about the cooling. Josh
Howdy... I do have the video. It's uneventful, although you can see some smoke when the motor fails... Here's a photo of BL4.
You can see in this graph how all the other motors started cooling down at the point that motor 4's temps skyrocketed. Hmm....
I would pull the PD board off and check the Caps on the bottom of the board. Take a pic. Also please post the video. Thanks! josh
The other motors begin cooling because I was landing at that point. I was only 4-5ft from the ground when this happened... I'll work on the other items, and on getting you some video to watch... Best, Ben
Here's the last minute of the video... The copter seems to handle the loss of the motor well. With a light load, I'm sure I could have maintained altitude for a short while... Removing the board now.... Ben
Update... I tried switching over BL3 and BL4, and it appears motor 4 is fine. Motor 3 (when attached to BL4) was still giving problems... So, it's definitely BL4. I have another BL from an previous board, so I will try to unsolder one of those and use it on here... By question is... why and how did this happen? I have NO clue... Argh! Any tips from replacing a BL module in a PWD board? B.
What can you guys tell us about heat sinks? Is everybody using them? What kind? And how to install them?
If it gets even remotely warm where you live (80*+) then heat sinks are a must for the 5D. In 90* temps here in Phoenix I was running right around 100*C on the BLs. Once I added the heatsinks I was running around 90*C. Once the temps went over 100*F here my BLs were in the 100*C range again WITH the heatsinks. If I hovered for more then about 5 seconds the temps were climbing even higher. I had one flight where I had a BL hit 113*C. I called it a day after that. Josh
I have them and will install them, but I'm now trying to figure out on a day with an ambient of 65 degrees, why this BL failed... Also, upon inspecting the board, it appears that the copper trace of BL#3 where it connects to one of the motor pigtails has started to lift. Is there any way to fix that? Yikes! It feels lie this board is a lemon! Ben
Yup... Good news! The copper trace has now come completely off... I say good news, because it was on my shop table, and not up in the air!!!! I'll get a photo to you shortly... Best, Ben