IRIS+ Battery Issue

Hey all,

I have been having a ball with my IRIS+ that I got as a Christmas gift (from myself :wink: ) and up until now I have had no issues. It’s been fun learning to fly as this is my first aerial rc vehicle and have no complaints. It is SOOO easy to fly!

Yesterday, however I had my first crash. This was a heart stopping experience, but I did have my GoPro on the gimbal so I got great footage, that’s a plus right? I ran over and luckily I found no damage to anything and just had to clean off some mud. I just had a chance to download the logs and I’m a little confused at what I am seeing so I was hoping if someone could verify me.

It seems that the battery voltage dropped very rapidly, from full charge to under 7 volts in this 58 second flight. I am confused at the fact that I had just got this battery off of the charger. It had the green LED and had been on the charger for about 4 hours so I assumed that it had to be fully charged.

A few minutes ago I plugged the battery back into the IRIS+ and, using Mission Planner, watched the battery voltage start at 11 volts and drop to about 6.5 in a minute. I put it back on the charger but the charger LED stayed green, indicating full charge. I put my spare battery on to charge and it immediately changed the LED to red. I thought it was a fluke thing so I put the first battery back on and the LED went to green. I put my spare back on and it has been a red LED for about 30 minutes now.

I’m thinking that the first battery might have something wrong with it but I wanted someone to verify my findings. I attached every file that came with the log in a zip file.

Forgive me, as you will see that the crash was basically my fault. You will see an RTL that I forced it out of because it looked like it was about to hit a power line. I did this because I saw the yellow LED blinking on the back of the IRIS+, thought it lost GPS and panicked. I didn’t want it to try to RTL without GPS and possibly hit the power line so I flipped it to AltHold to try to recover. It did not and now I have an up-close video of my front lawn.

If you’re still with me after my long explanation/rant please take a look at the log and tell me if the battery dropped off quickly and might have something wrong or I did something wrong or anything else that might have happened.

Thanks in advance,

Not good, The battery should start off at 12.6 volts and drop from there. Each cell should not go below 3 volts ever.
So 3 X 3 = 9 volts. Yours shows 7 volts at the end and only 10.7 at the start.

Most chargers will refuse to charge a battery below those levels and the battery may have a bad cell. Don’t know what charger you have but I think you need a new battery. Should be under warrantee.

You may want to pickup one of these guys as it will tell you about each cell: … S_8S_.html

Don’t know why 3DR doesn’t sell one of these. I used a voltage meter from Radio Shack and then I upgraded my charger so that I would not have to wait 4 hours to fly. It also has a storage charge mode and tells my about each cell too.


I wish the people at 3DR would put a larger door on the IRIS+ to better accommodate the wire & connector. Getting the door closed, you have to have your mouth held just right and know that every successful closure is one closure closer to damaging the door or the light or both. Yes, I do have duct tape inside to “protect” the wire and light, but it doesn’t make me feel that much better.

There’s got to be a better way to insure the battery does not shift then to rely on the door, the light, and it’s wire to keep every thing compressed into place.


I have the stock charger that comes with the IRIS+. I tried to plug it back into the charger one more time and I was surprised that the LED changed to red. But then I noticed that is had the 2S instead of the 3S light blinking, so I’m going to assume you are correct that there is a bad cell. I did order that meter you suggested from hobbyking, thanks for that. I guess my next step is to call 3DR.


Just to let everyone know, I had a confession from my younger brother earlier today. It seems that he had took a joy ride with my IRIS+ before I got home on the day of my crash. He said he flew it for about 10 minutes and then took the battery back in to put it on charge. When he went to plug in the balancing plug he said it sparked on one of the pins. He saw that he had the plug upside down, so he flipped it over and plugged it in. He was had already left by the time I came home and my wife, being the wonderful person that she is (still haven’t figured out what she wanted), had the IRIS+ already setup to fly and I just had to plug the battery in.

I’m going to assume that the spark he saw was one of the cells discharging completely because of the wrong polarity when he tried to plug the balancing cable in upside down. I plugged the battery back into my charger and let it set for 8 hours and it finally started charging correctly. I took it out and flew it (very close to the ground) for a full 10 minutes and currently its back on charge with all the correct LEDs indicating correctly.

I think it was a perfect storm of problems that led to my crash and not a bad battery but I do thank you for your advice. I do have another question however. Upon further inspection, I noticed that the top two mounting plates of the gimbal are broken. I’m talking about the one that actually attaches to the IRIS+ with the two allen head screws and the one on top of the shock absorbing rubber balls. Does 3DR sell parts for the gimbal or could someone point me in the direct of where to get parts. It looks like it will be fairly easy to fix if I can get the parts. I attached a picture of the broken parts just to be clear.


Looks out of stock right now though. Time to hide the batteries. Sorry about the problems.