Iris+ Random Crash In Flight - Lost In Water

Hey DIY Drones,

This is my first post here, but I felt I would share my story and log with the community. Today I was out for a rather routine flight of my Iris+ from 3DRobotics that included an Auto Flight followed by some manual flight in Loiter mode directly after. No heavy wind or outside weather factors to worry about. A nice 70 degree evening here in St. Pete, Florida. Normally I fly the Iris+ with the Tarrot 2D gimbal and a GoPro but thankfully today I did not. I was getting my flight plan ready for a filming I was planning next week and was getting down the flightpath before mapping out the angles of the shots.

After flying in auto mode for the duration of my flight plan, I took over in loiter mode to do a short flight around a fountain I planned to shoot. I had just had the aircraft fly the same path in auto mode and I like to practice my flights manually incase I have to assume control in the middle of a shoot. About halfway through the maneuver the Iris+ started to wobble and descend like it was losing power suddenly. I kicked the throttle to full power and directed the drone away from the water (knowing a crash was almost imminent) but the drone failed to react to the controls and crashed in the lake I was flying over. About 20 feet from shore too. *Insert sad face* The drone now sits at the bottom of the lake in about 10 feet of water. I was unable to recover the aircraft today but and hoping to in the morning. 

Attached is a link to the log of the flight. So far looking at the data I cannot see anything to explain the sudden loss of control. The only thing I have really notice was a drop in battery voltage at the end of the flight, but I am unable to tell if this is because of the loss of the aircraft or there really was a sudden loss of battery voltage. The HUD never told me I had less than 70% battery during the flight and even so a loss of battery should have caused a return to launch. 

If anyone out there has idea what might have caused this crash, I'll take any input. With all luck I will recover the aircraft in the morning, but with the craft sitting in 10 feet of water for around 18 hours I am assuming a total loss. Sad. This craft seemed so stable in all other flights I've done with it (30+) and it was becoming a workhorse for me. 

Thanks to any who help! 



2015-03-28 19-09-14.tlog

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  • thanks!

  • Yeah, it should probably be milliohms, certainly way less than one ohm. And don't "pitch it", rather, recycle responsibly:

    I checked my charger and it does have a function to indicate battery resistance per cell and total in milliohms, I will start using it TODAY.

    RC How To | Proper Li-Po Battery Disposal | RCCOH
    Properly Dispose of a Li-Po Battery - Battery Disposal
  • Well, I have the charger that came with the Iris+, but I generally use a "HiTec multi-charger X4AC plus"  (

    I can probably figure out how to check the internal resistance if it does indeed support that function, but what am I looking for?  (What units is it measured in, what is a good range, when is it getting old?)


  • How do you do that?
    • +1 for Erik's question.

      I haven't responded here before, but I have been learning a lot from this discussion. Thanks everyone (minus flamers). I have developed a routine that I follow with batteries, more luck than wisdom:

      1. I always recharge all used batteries after all flying sessions, I have a total of five. And I always use a fire safe bag in a fire safe location.

      2. I use a fine point Sharpie permanent marker to place a mark on each battery every time it is charged.

      3. I select batteries for use based on fewest charges, and I check total voltage and balance on every battery before placing it in my IRIS+.

      I use one of these for the check:

    • Good ideas except for recharging after flights if you mean fully recharging.  Better for safety and battery longevity to store them at an intermediate storage voltage... some chargers even have a setting for that.

  • Between this and another thread on DIY Drones I'm learning a crap load about batteries. I think I need to start tracking usage of each battery from now on.
    • I'm so used to flying gas powered fixed wings that this transition to battery powered drones and aircraft has been a learning curve. With gas powered you could have some left in the tank all the way down to zero where with batteries if you have some left in the tank but can't maintain voltage, your coming down hard. Def been a learning curve. 

      That being said I love my Phantom but the price for all the add on is just a little but much for me. That's why I fell in love with my Iris+ right out of the box. She was stable, responsive, and didn't cost me upwards of $1500 for a drone with a gimbal and tablet based ground system. Oh well, back to the phantom for awhile. I'm either taking this lost and getting a Iris+ again and being super cautious this time or going to custom build my own system. I want to be able to fly my 5D Mark III for video buttttttt I don't have thousands to shell out on a freaking beast of a system. That being said I'm looking at two Iris+'s so maybe I should just bite the bullet hahaha. Kidding my lesson was learned on this one! 

  • Hello again everybody!

    Sorry I just began a new position and have been busy adjusting to a new work life. I went out the next 2 days after I lost the aircraft to try and recover to no avail :( She is a goner. I was initially more upset about the loss, but I have lost aircraft before that took months if not years to complete fully so I've gotten over an easily replaceable quad pretty quick.

    By now we all know the voltage was the cause of the crash and I do agree that's what brought this baby down. I read someones post (sorry I cant remember who I just skimmed the replies real quick) that suggest I mixed up the batteries and I know with 100% I pulled this one off the charger with indication that it was full. That's why I have been so puzzled as to why I had such a quick drop. I've had batteries go bad on me before, but that not <50 flights quick. 

    I've already begun looking at what to replace this copter with. So any suggestions I'll take it! Thanks for all the feedback, and don't worry I can handle a few assuming jerks using personal attacks! I may seem new but I have just never posted here because I've never needed to! Looking to become a valuable member in the future though! 

    Thanks again!

    EDIT: Read some more and I was stupid and just trusted this battery off the charger and didn't check it with the HobbyKing checker I have. Since the battery and quad were still relatively new I didn't even think to double check.

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