I have already submitted all my information to the IRIS Hardware support forum, so I thought I'd share this video with my fellow IRIS owners. I had heard about the IRIS props just stopping but I thought I was immune since I have been having so many good flights. As you will see from the video, the IRIS went down from a pretty good height. Luckily into grass. The Tarot Gimbal does a good job of keeping the camera still even during the fall.
Looks like I'm out a Tarot Gimbal mount, one arm and 4 props because it cratered. The gimbal PCB and motors are all still good. Even the GoPro survived as you will see.
Now I have to figure out how to get my new parts.
Here's the video:
Replies
Watch out for the male XT60 connector pins making not a good contact with the female battery connector.
It just happened to me this morning as I was stuffing the cables and trying to shut the battery door, IRIS got a reset multiple times. I starting playing with the cable to find out pins on the male XT60 somehow crushed causing the resets. Could this be your problem?? Battery was a Turnigy 4S 2650mAh 20C.
Used a hex screw driver to expand the pins, see pict.
As a side note, I also tried a Zippy 4S 3000mAh 20C battery, its a bit tight fit, but its giving me about 12-13 mins throttle time depending how aggressive I fly. Just be careful stuffing the extra long battery cable and don't over heat the battery, otherwise it will be difficult to take it out ;-)
Hi Oliver,
You've done a great recap of notions that were covered during a drone piloting course I am taking. If you have no objections, I'll translate in French and adapt parts of your post for the blog I am writing for my classmates : http://blog.exodrone.com. I'll credit you as the source -
Best
Fred
Here is some very good information that was sent to my by Craig at 3D Robotics after the findings on the crash.
All You Need To Know About - LiPo's
INTRODUCTION
Lithium polymer batteries or LiPo batteries are currently the most
efficient power sources available with the highest possible specific
energy. This means that you get more power and capacity from a smaller and
lighter battery. To accomplish this, a different technology is used
compared to NiCd, NiMH, and Li-lon batteries; subsequently, slightly
different handling and charging applies. Please read the following safety
guidelines to familiarize yourself with the specifics of these batteries.
*TECHNICAL*
Some technical terms explained: Voltage and capacity
Because 1 Lithium element or cell has a (low) fixed voltage of 3.7 V. most
batteries or packs are built up from a number of Lithium cells in series.
The amount of Lithium cells in series is the indicated by the letter 's'
e.g. 3s battery. You can determine the total nominal voltage by multiplying
this number with 3.7V. In our example 3s battery gives 3 x 3.7V = 11.1 V.
this is an important value when It comes to choosing charger parameters,
the charger settings must match the LiPo. (See chapter Lithium polymer
batteries)
3.7V is the average voltage; LiPo can be charged up to 4.20V and discharged
down to 3.0V per cell, any lower or higher in voltage and the cell will
almost certainly be damaged and will become unstable which can be very
dangerous (fire risk).
The capacity of the battery is indicated with 'mAH' e.g. 1500 mAH. This
tells you how much energy it can contain. MAH is the abbreviation of milli
Ampere Hour or 1/1000th Ampere Hour. (1000 mAH = 1Ah)
The capacity tells you how long it takes to discharge a battery of 1500 mAH
can provide 15000 mA (milli-Ampere) or 1.5A during 1 hour, or twice as much
(3000 mA or 3A) during half an hour, ect. Because Lithium batteries come in
variety of capacities, the 'C' rating is used to determine the maximum
allowable current x C value e.g. 1500 mAh x 30C = 45000 mAh or 45 A.
Maximum allowable discharge current is usually between 10C and 50C, *maximum
charge current is always 1C*. (Whilst some LiPos can be charged at higher C ratings up to 5C, doing so will shorten the life of the battery, so it is
good practice never to exceed 1C)
In case of a 3s 1500 mAh battery with a 30C rating, the maximum
(continuous) discharge is 45A and the current is 45A and the charge current
is 1.5A (15000mAh x 1C = 15000 mA or 1.5A)
CHARGING LITHIUM POLYMER BATTERIES
As mentioned before: if the voltage of a single Lithium cell exceeds 4.20V,
it will become unstable. When this happens the cell will over heat, swell
up and rupture whereby the electrolyte can spill and catch fire! Because
the technology of the LiPo batteries is different from other batteries, you
must always use specialized LiPo charger. *Under no circumstances attempt
to charge a LiPo with a NiCd/NiMH charger.*
The charger parameters must match the LiPo and must be verified each time
before you start the charging process:
- The programmed number of cells must be the same as the LiPo or the nominal voltage must be equivalent. A 3s must be charged with 3s or 11.1V
setting etc.
- The charge current must never exceed 1C (for a 1500 mAh battery: 1.5A)
- A balancer must be used to balance the voltage of individual cells during charge. (See chapter: Balancing)
To further avoid fire risk always respect the following precautions:
- *Never charge the battery unattended*
- If you have a multifunction charger, thoroughly read the instructions and make sure it is in LiPo mode.
- Verify that the total voltage in the pack never exceeds the amount of cells the amount of cells in the pack may never exceed (5 x 4.20V =) 21.00V
- Put the charger and battery on a non-flammable surface, like a ceramic tile, during charge and make sure no flammable objects are within a radius of 1m.
- If possible, put the battery inside a special LiPo bag or in a
fireproof container during charge.
- Never charge inside a car, clubhouse or garage and if possible, keep a dry extinguisher or fire blanket ready. Never charge the battery while it
is in the model.
- Stop charging immediately if the battery gets warm or swells, disconnect the pack and put it in a safe place for observation for a few
hours.
- Never charge or recover a battery pack that damaged/bad/swollen cells, or cells that are below 3.0V
- Use properly insulated connectors and charge leads at all time.
BALANCING
Because the charger only measures the total voltage of the pack during the
charge, the individual cells must all have the same voltage at all time.
Otherwise the total pack voltage might be correct, but some individual
cells might already exceeded 4.20V. E.g. a 2s pack that has reached 8.4V is
fully charged, but if one cell has a voltage of 4.10V, the other cell will
be at 4.30V and will overheat. To avoid this situation, specialized
balancing circuits or balancers are available or are built into the
charger. Make sure that the connector type of your balancer match the
battery and always check if all cells are recognized. (The indicated number
of cells on the balancer must match the number of cells in the pack.)
*Always use a balancer during charging *and preferably use a charger with integrated balancer. If a separate unit is used, always use an active
balancer that has the ability to interrupt the charging process if
necessary.
*USING LITHIUM POLYMER BATTERIES*
Lithium Polymer batteries can store a tremendous amount of energy and
therefore must be handled with care. A fire risk exists and precautions
should be taken to minimize this risk. There are two main factors that can
possibly cause a fire during use:
- Physical damage: one or more cells are punctured, deformed or exposed
to extreme conditions
- Internal damage: one or more cells are punctured, deformed or exposed
to extreme conditions.
- Internal damage: one or more cells are discharged too fast or too deep.
To avoid this please respect following guidelines at all time:
- Never expose LiPo batteries to extreme heat (heater, fire, flame, exhaust, sun); never leave them inside a car for a long time.
- Never puncture a LiPo cell, as it will immediately catch fire. When installed in the model, make sure it cannot touch protruding screws, or
sharp metal parts. Make sure the battery is well protected in the case the
model should crash.
- Never put a LiPo in your pocket, as key chains or other objects may
puncture it.
- Do not deform the battery. If it should have deformed during a crash or transport, never try to force it back into its original shape but
dispose of it safely. (See chapter: disposal)
- Always transport LiPo batteries in a fireproof case where it cannot come in contact with other objects.
- After a crash, put the battery in a safe (fireproof) place for observation for 24 hours before using it again. It might have suffered
internal damage, which might cause a delayed reaction.
- When one or more cells have swollen, dispose of the battery pack immediately, do not try to recover it or recuperate separate cells.
Reassembling packs from different cells is dangerous if not done by
professionals. Furthermore all factory assembled packs are composed of
matched cells, when random cells are used to compose a battery packs, the
different characteristics of the cells will affect performance adversely
and this can be dangerous.
- Don't let the LiPo cells come in contact with water, if this should happen; dry them quickly with a towel.
- *Never exceed the maximum stated discharge rate. (e.g. 30C)*
- Never allow the battery to short circuit. Use properly insulated connectors and isolate them additionally during transport if necessary.
- Never allow a battery to exceed 60°C (140°F) at any time.
- Never allow the pack to be discharged below 3.0V per cell; preferably use an ESC with LiPo low voltage safety cut-off. Over discharging causes
permanent damage to the cell.
- When one or more cells are below 3.0V after use, don't try to recharge
them.
- Stop driving as soon as you notice a drop in power. However tempting it may be to continue, you will almost certainly discharge one or more
cells in the pack.
- *After use, let the battery pack cool down completely before
recharging.* Failure to do this will result in the rapid deterioration of your battery pack and can be dangerous!
- When the battery consistently gets very hot after use, check the gearing and make adjustments if possible. Discharging batteries at maximum
discharge rate for prolonged times will shorten the life of the battery
considerably.
- Disconnect the battery from the ESC or load after use avoid slow over
discharge.
- Make sure the battery is well ventilated in the model to avoid heat
build-up or thermal runaway.
- Don't let children handle these batteries without adult supervision.
STORAGE OF LITHIUM BATTERIES
For long time storage it is recommended to
discharge/charge the batteries to 50-40% of their capacity (or 3.8V per
cell). Never store LiPo batteries fully charged, not even for a week, the
performance will degrade noticeably. Keep the LiPo batteries stored in a
fireproof location at room temperature.DAMAGED LITHIUM BATTERIES AND
DISPOSAL Please take great care when a battery has been involved in a crash:
there might be visible and/or invisible damage to the cells, which may
cause a violent (delayed) chemical reaction. If possible, remove the
battery from the model as soon as possible and put it in a fireproof
location for at least 1 hour for observation. Be careful as the cells may
be very hot and they might be leaking electolyte; wash your hands with soap
immediately. Should you get the electrolyte in your eyes, flush generously
with water during 10 minutes and seek medical attention. Wait at least
24hours and inspect thoroughly before reusing the battery.If the battery should catch fire immediately after the crash, don't attempt to remove it
from the model, use a fire extinguisher!
When a Lithium battery pack is damaged or needs to be disposed of, proceed
as follows:
- Submerse the battery into a container filled with about 10L of salt water. (Add a cup of salt per 10L)
- Leave the battery submerged for 2 weeks; this will slowly and safely discharge the battery until the voltage has dropped to 0V, which eliminates
the risk of any chemical reaction.
- After 2 weeks, place the battery in the trash.
Mark,
When you are looking at your logs, are you downloading them from the IRIS with Mission Planner or are you physically taking them from the SDCard inside the PixHawk? If you download them from Mission Planner, it will appear that they just stop, but in reality the logs are getting truncated. That was my exact situation.
You get a much better reading of your logs when you get the .bin files right off of your SD Card. That's why they sent that SDCard adapter with the IRIS.
I discovered the hard way that when LIPO batteries experience too many deep discharges they suddenly drop in voltage like "off a cliff" instead of slowly discharging.
So, here is what I take from this. I HAVE to be watching the droid planner to keep an eye on my voltage levels while flying. At first, I thought that the Droid Planner was just a thing you would use if you want to fly autonomously. It appears that flying with the gimbal will require me to NOT be able to rely on the battery failsafe, or I should set the failsafe to a higher voltage than 10.5VDC, maybe 10.75 (unless someone else has a recommendation). The reason is because sometimes I have the IRIS at such a height that it draws down so much current just to maintain the automatic descent.
These are my recommendations to everyone who flies with the gimbal, take it or leave it.
Ken,
do like I did, get a $2 battery monitor/alarm and disable the battery failsafe on IRIS.. These little external devices work perfectly, you will have enough juice to land as soon as you hear the low battery alarm.
I personally think failsafe doesn't work properly, after loosing my APM2.6 (radio signal out of range failsafe was active) and experiencing intermittent low battery failsafe performance on my IRIS, I disabled it completely and have been using the external monitor/alarm on the IRIS and have a piece of mind.
I also experienced that Mission Planner/ IRIS does NOT calculate battery consumption properly - for example after the external battery alarm goes off, Mission planner still displayes around ~20-25% juice left, so don't rely on that either (yes my fully charged battery size and reserve limits are set properly on MP)
Well when it comes to customer service, I called them once and told them I was disappointed with IRIS and wanted to return it. He said "did you read the fine print at the bottom of our web site"
I kept the IRIS, upgraded the FW to RC5, it made a difference.
I also find it very difficult to fasten the props w/o being able to hold the motor body. I have been using a pliers to grab the bottom of the prop shaft - so IRIS fliers make sure your props are fastened properly.
Well sorry for venting here but I hope these will help you and many other IRIS fliers out there.
Joe, thanks for the advice. I've made a determination that despite the simple instructions that are provided to us on how to charge, plug in and watch for "puffy" batteries, I need to become an expert on LIPO battery maintenance - and get all the necessary tools to do so. This charger doesn't seem to be all that is necessary to do it. Like finding a good internal resistance tester, and investing in a better charger than the one that is provided with the IRIS.
Simply looking for a "puffy" battery pack is apparently NOT the only indication apparently that your battery is damaged, as mine are still the same thickness that they were when I bought them, and I'm talking within a 16th of an inch.
So, what do you use for your batteries?
Well, after 3DR reviewed the logs, the battery and the IRIS, it has come to this. It was pilot error. The exact terminology was:
After 5 flights completely discharging the battery to levels that will
damage the battery Flight 19 was a normal discharge
Flight 20 was the final one where the vehicle crashed:
You can see at the beginning that the battery was not fully charged and
that by the end the battery was dipping to the 10.5 low voltage cuttoff.
At that point the battery was so low it was taking 80% throttle to hover
You commanded full throttle for a 11 m/s horizontal velocity and a 1.5 m/s
climb rate
at which point the battery voltage collapsed such that the power supply
could not maintain the required minimum input voltage to the Pixhawk and it
browned out and terminated the log.
Findings as to cause:
- The pilot commanded full output power from the vehicle late in theflight causing an almost fully discharged battery to fully collapse to a level where the power supply to the autopilot could not be sustained. The autopilot and motors subsequently turned off in mid air.
Contributing Factors
- The pilot commenced the flight with a battery that was not fully
charged.
- There is a history of a battery or multiple batteries being damaged by deep discharging on several previous flights.
- The pilot may have been using a battery that had previously sustained
damage from deep discharging.
Called up 3DR, and the good people on the support line say I won't have to worry about the replacement parts. I'll be getting them in the mail soon. Whew! I'm glad I selected a 3DRobotics product.
the 3DR response to your crash is precisely why I chose to buy the IRIS instead of say a DJI phantom or others.
Support!
HZL
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