Hello, last Friday I had a really weird experience as I was preparing for a job. When I plugled the battery to my cinestar, nothing happened, nothing at all. Motors didn´t start, no beeps at all. I had 2 batteries in paralell. First thing I did was change the paralell conector to another. Still no sign of power. Changed for another paralell harness, but nothing. Checked the batteries again, both 98%. Pluggled just one battery, nothing. Plugled the other one by itself, but still nothing. Got a third battery pack, and no sign of power. Checked to see if I had some wiring out, but all seemed ok. After a while I plugled the battery pack again and after about 5 seconds (it wasn´t straight away as usual) I heard the motor beeps! Unpluggled the battery pack and pluggled back in, nothing. Then pluggled back again and it worked. After this time I repeated at least 20 times the procedure and all worked fine. Spent a whole battery pack on a hover, with some gas punches, and all seemed back to normal. Came back to the shop, disassembled the whole boards looking for some kind of bad contact, but all seemed fine. I unsoldered the main leads and made a brand new one, reassembled the boards and it still works fine. No sign of the problems I had Friday. Has anyone had similar problems before? Here follows the specs for this copter: Cinestar 8 QC-3328 with Xoar 14x6 Mikrokopter HW: 2.1 Mikrokopter SW: 2.06e Mikrokopter Power Distribution Board with BL Crtl 2.0 Gens Ace 10A 4S battery packs Futaba Sbus Receiver I have the flight ctrl board set to "ignore magnet error at start up" and letting it start without GPS fix. Thanks for your help. Marcelo.
Hi Marcelo: Whoa....that really is a strange experience. Did you happen to see any LEDs light up when you first plugged the LiPo in? If so, were they on solid or flashing? Andy
I had a similar issue with my CS8 last year, pretty much same specs as your build. I had a pretty bad crash, replaced a couple booms and the NAVICTRL, so I had to reprogram a few things. While I was doing test hovers in 1-3 minute intervals, the copter lost power and dropped (luckily only a couple feet off the ground so no damage). The strange part is once it landed, the power came back and the motors chirped at me. Long story short I had a bad EC5 connector on the copter power lead. It had carbon build up that caused it to short when the copter was flying/vibrating. Replaced the connector and no problems after that. Sounds like you might have had a bad/old connector on the copter itself. Especially since those are older components leading me to believe the rig has been around for a while. I would still put it through some more testing before flying with payloads, just to make sure its not something else. Good luck!
Thanks for posting that Alex -- it suggests that Marcelo should look for single point failures in the LiPo power supply between the LiPos and the aircraft as only that kind of failure would seem to kill a pair of LiPos in parallel. Andy.
I would agree that a very close inspection (and maybe complete replacement) of some EC5 connectors might be in order, especially the one on the leads coming directly from the power distribution board. The sparking that happens most times when LiPos are connected can leave a small bit of carbon, and that could conceivably accumulate over time to the point where it could cause an intermittent connection on one of the EC5 terminals.
Alex, I also suspect the only past subjected to a failure on this situation would be the main power leads. So as I mentioned, I made a new lead yesterday and resoldered to the PDB. I'm VERY curious to take a closer look to the EC5 that was here, and inspect for signs of carbon (I hope to see some carbon there). I'm heading to the shop and will open the EC5 and take some pictures to post here. Thanks for your help.
Steve, I will also inspect battery pack EC5's, but these packs are brand new, and it would be really odd 3 of them having problems. But we better be sure... The main battery lead (this setup has only one) was replaced yesterday for a brand new one. Regards
Well, I opened the EC5 connector and it looks nasty! The reason I couldn't get power on the first attemps could be the bad contact due to to residues of carbon, and after trying a few times it could have "cleaned" the bad spot and make contact again. Take a look at the pictures and you will see the tips are pretty bad, but there are signs of carbon also on the sides. I will inspect all EC5 connectors on copters I have at the shop, and will start replacing them with XT90-S sparkless plugs (attached). Will also continue with more flight tests with this cinestar, and report anything uncommon if appears. Thanks again for all your support. Regards, Marcelo .
Holger Buss (the creator of MK) had a similar problem with that type of EC5 connector. I much prefer the ones from ProgressiveRC. They're all I use, and they've been super reliable. http://www.progressiverc.com/ez-solder-ec5-connectors.html
Andy, if you take a closer look, you can see where the rotating coils should touch with the inner pin, but actually they are covered with some type of corrosion an carbon .
Steve, these are indeed much better design, with no moving components. If it starts to loosen, you can always spread the parts apart and adjust tightness.
It looks like some form of electrolytic action -- if it was high current arcing (such as you see at the tip of the connectors) it actually melts the connectors. Have you been flying in high moisture environments? Andy.
That might explain the problem. Can you get WD-40 Electrical Contact Cleaner in Brazil? See http://wd40specialist.com/products/contact-cleaner/ That might help reduce the problem. Andy.
Please note that ordinary WD-40 (the lubricant) should not be used around copters. It's highly flammable!
Wow those connectors were nasty!!! Glad you figured out the issue, those XT90 Anti Sparks will be a great replacement. Let us know how everything goes!
Awww. You're no fun, Steve. (But you are correct -- what I am referring to is NOT standard WD-40!) Andy