Power drop after 1-2 minutes

Discussion in 'Walkera TALI H500' started by RichieG, Feb 5, 2018.

  1. RichieG
    Offline

    RichieG New Member

    Joined:
    Feb 5, 2018
    Messages:
    4
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    Melbourne, Australia
    Ratings:
    +0 / 0
    Hi guys and gals,

    Quick backstory. Not a completely novice pilot. Have a hand-built tricopter and foamy fixed wing but it's been a while since I got into drones; having shelved all that a few years ago. Been keen on getting into FPV again once I had my workspace/garage setup (and enough money again!) so decided to get a Tali H500 on special at half price. I read some of the problems people were having, usually with fly-aways and such but luckily I haven't had any of that.

    I did initially have some issues with the first flights trying to use GPS mode too soon and not having calibrated the compass correctly; the results were as expected. Drifting and such.

    Anyway, I've got the latest firmwares on the Devo F12e and Tali H500 and have re-calibrated compass etc. Trying to keep it at a hover for at least 2-3 batteries just to give the GPS/compass time to become more accurate.

    But my biggest issue, which has caused numerous crashes has been this:
    After a couple of minutes in flight, power to some or all of the motors slowly drops and no matter how much throttle I give it; it just drops. Not like a rock but quick enough to break the landing gear and damage the worm servo mount. The gimbal has taken a couple of hard knocks too and bent it but luckily hasn't smashed anything.

    Initially I thought it may have been because of ring vortex effect, if I went to descend however I couldn't isolate it to that as it would also happen in a hover or while trying to climb.

    A mate of mine suggested a bench test with the lid off, which I did just now.. and my brother-in-law (competes and ranks in FPV drone racing) suggested that the ESC's may be overheating as the battery voltage doesn't seem to be the issue. I have 3 batteries and the result is the same with each one.

    After a couple minutes running the motors at 50% throttle, they slowed down for about 20-30 seconds (to about 10-20% power) before coming back up again. I let it run for a few more minutes and it did it again! The ESC's don't feel scorchingly hot to touch however it was difficult to tell if it was happening to all motors or just some.

    What the hell is happening?

    I just got a DJI Naza V2 in the mail and am pretty close to getting six aftermarket ESC's and replacing the stock ones.. however if anyone can give me any indication as to what this sounds like; especially if it isn't the flight controller because I'd rather not have to go to all the trouble of a Naza conversion only for it to not make a difference.

    Sorry for the long post. Thanks for reading! Any help appreciated!

    Cheers,
    Richie

     
  2. bjr981s
    Offline

    bjr981s Moderator Staff Member

    Top Poster Of Month

    Joined:
    Sep 19, 2015
    Messages:
    5,034
    Likes Received:
    311
    Trophy Points:
    83
    Location:
    Sydney, Australia
    Ratings:
    +405 / 13
    Does it do this in what Flight mode? Man, GPS?

    The H500 uses a barometer to determine height. If the barometer is faulty it will cause erratic changes in altitude.

    The Barometer is in the FC.

    The H500 does suffer badly from VRS but that does not sound like the issue you are having.

    Have you played with Mission Planner? If you have you have most likely corrupted your FC.

    If you did a FW update via MP then that will definitely screw it up.

    Cheers
     
  3. RichieG
    Offline

    RichieG New Member

    Joined:
    Feb 5, 2018
    Messages:
    4
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    Melbourne, Australia
    Ratings:
    +0 / 0
    Hey mate, thanks for the reply!

    I've been testing in manual mode, just keeping on the sticks to keep it in one spot. I haven't touched mission planner at all.

    Firmware updates have been done directly with Serial Angel, first to 2.2 and then back to 1.2.

    Today's update after some bench tests and now finally over the weekend with flight tests:
    It seems to have been an issue with the battery that came with the heli. I guess it was old and crappy. I had 2 more arrive the other week so I extensively bench tested all 3, new and old and the 2 new ones do not seem to have any issues.

    I took it for a spin around the back paddock and put the new batteries through it without any drop! Looks like it was the battery after all. Perhaps that's why it was on special at Hobby King!

    Buyer beware! :)

    I think I can call this one case closed!

    Cheers, Richie
     
  4. bjr981s
    Offline

    bjr981s Moderator Staff Member

    Top Poster Of Month

    Joined:
    Sep 19, 2015
    Messages:
    5,034
    Likes Received:
    311
    Trophy Points:
    83
    Location:
    Sydney, Australia
    Ratings:
    +405 / 13
    Glad you got it sorted. Use a LiPo checker on the old battery and see if it has a bad cell. or one cell significantly down from the others.

    If 1 cell is significantly lower it will never charge correctly on the OEM charger.

    It can be fixed but it will take a Smart-charger. Preferably a hybrid.

    Cheers
     
  5. RichieG
    Offline

    RichieG New Member

    Joined:
    Feb 5, 2018
    Messages:
    4
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    Melbourne, Australia
    Ratings:
    +0 / 0
    I'm using a Turnigy Accucel 6 charger at the moment but I suspect it's been a bad battery since I got it. After I ran it down to the point where my radio was complaining of low voltage, it puffed out a bit and was hard to remove. Even before then, it was giving me the power drops.

    Since sticking with the 2 newer ones, I've had a few more flights of about 10-15 minutes each and no problems at all. Actually starting to enjoy it now instead of writing it off an expensive mistake!

    Cheers.
     
  6. bjr981s
    Offline

    bjr981s Moderator Staff Member

    Top Poster Of Month

    Joined:
    Sep 19, 2015
    Messages:
    5,034
    Likes Received:
    311
    Trophy Points:
    83
    Location:
    Sydney, Australia
    Ratings:
    +405 / 13
    Ah, thats great. It's a fun machine
     

Share This Page