Routine fight. Took off with battery at 61%. Flew for 2 min. Landed and took off a 2nd time battery at 52%. Flew for about 2 min 41 sec (battery at 33%.) At 2 min 42 sec the battery dropped to 8%. Warrning sounded. 5 seconds latter I realized the landing gear was coming down and Inspire was attempting to land at sea (7% battery.) I attempted to fight landing and bring Inspire back but was not succesfull. Lost at sea

I have 4 batteries that a routinely rotate. All batteries have been upgraded to most recent firmware. All batteries have been charged 9-10 times. The battery that failed had self discharged to 61% before failure.

Expensive and hard lesson.

Hi miketeel,

Very sorry to hear of your loss, hopefully DJI will determine it wasn't your fault and replace it.

We've heard about this a few times here on the forum.   The new rule is to never fly without a fully charged, 100% battery.
Seems like it only occurs in the situation you decsribed.   At least that's the conclusion I've come to.

Again, very sorry to hear about what happened.   Make sure you save your flight to the cloud in the app and report to DJI immediately.   Hopefully you'll be flying again soon!

Jim

NEVER, NEVER, NEVER launch without a fully charged battery.

There are too many reported cases like this where people have used half discharged batteries and hit the cliff edge voltage either losing their Inspire or coming close to it.  Even after reading all the warnings I recently took off with a battery at 65% (assuming it was fully charged) and 6 mins in I get a low battery warning (set to 30%) only to see 8% remaining.  I landed immediately with just 5% showing.  I was lucky.

Analysing my battery logs I last used and charged the battery 12 days earlier and had not carried out a full discharge/recharge cycle since it was new.  It had flown 18 times. This is not a fault with the Inspire 1 or the battery firmware.  It is a well known performance issue with the LiPo battery chemistry used.

Scotflieger Posted at 2015-6-22 06:26
NEVER, NEVER, NEVER launch without a fully charged battery.

There are too many reported cases like  ...

This was exactly what I was going to say!

I wonder if DJI will update the firmware of the Inspire 1 so you can't fly below a certain battery percentage i.e 80% . However, DJI are into making money so buying another Inspire 1 would keep there bank looking happy.

I have been told by two different DJI technicians that taking off with a partially charged battery is safe...However, you should not fly a battery that has been untouched for a period of time...That battery should be discharged and recharged in order to function properly...There is a big confusion with this. I used to think that I can only fly two times because I only have two batteries, but you can fly for one shot, land the Inspire and continue using the same battery without charging for another shot...Just make sure you don't use that same battery if it is too low...I wouldn't fly it if 30% was remaining just because of the RTH function.

This is expected with Lithium Ion batteries...not just DJI ones but any Lithium Ion batteries. They need to be cycled and the cells need to be exercised to remain functional.

You need to charge batteries to full capacity before every flight does not matter if is at 8o percent. The internal a of the batteries will give you inaccurate reading until it resets its self and gives correct reading and by then you have lost the bird

pidetectives@ya Posted at 2015-6-22 08:10
You need to charge batteries to full capacity before every flight does not matter if is at 8o percen ...

Did someone from DJI say this? Normally battery capacity is estimated based on cell voltage.

SimplePanda Posted at 2015-6-22 09:20
Did someone from DJI say this? Normally battery capacity is estimated based on cell voltage.

No one from DJI said this...DJI said it is SAFE to fly on partially charged batteries!

Scotflieger Posted at 2015-6-22 06:26
NEVER, NEVER, NEVER launch without a fully charged battery.

There are too many reported cases like  ...

I agree and that is our official position.  However, I would have OP contact DJI and send them the Flight Log.  There may be something that they can do to assist.

Tahoe_Ed Posted at 2015-6-22 11:33
I agree and that is our official position.  However, I would have OP contact DJI and send them the ...

Ed, is it okay to top up a battery if it's been unused for a while, or does it formally need to be discharged/recharged?   

And if so, what is the process for discharging a battery anyway?   Is this where you run the batt until the Inspire won't start up again?

Would be great to have a clear procedure in place so the rest of us can avoid the same fate.

Cheers!

Jim

I've been reading about this problem for weeks now, so when I got my brand new Inspire back from LA repairs this week, I decided to try flying it with a battery that had self discharged over the 8 weeks I was without an Inspire. The battery was at 43% charge when I powered up the Inspire.

Both of my TB47's are circa January '15, and I had previoulsy flown them partially charged on my two older Inspires without issue. So my theory was that if I experience the problem, then it must be due to firmware and/or a newer generation Inspire.

So up my Inspire went. Knowing I could experience a drop at any moment, I kept it close by, and after about 2 minutes, the battery charge suddenly dropped from about 30% to 7% and automatically lowered the landing gear and began to land itself. Although I half expected it to happen, it was still disturbing to actually see it with my own eyes. So yes -- this does actually happen with partially charged batteries. And it does not appear to be a battery issue since it never happened before with these batteries on older firmware and older Inspires. All signs point to new firmware and/or newer generation Inspires.

What I don't know and didn't try is whether the result will be the same with a battery that discharged itself over time and a battery that discharged from recent use.

Abe Posted at 2015-6-22 12:14
What I don't know and didn't try is whether the result will be the same with a battery that discharged itself over time and a battery that discharged from recent use.

I don't know either, but I DO know some of the stories involve starting with a 100% charge, flying, landing, hiking a bit or otherwise delaying a bit (minutes, not days) and going up again with the same battery (now at 66% charge instead of 100%) and having the same sudden-power-drop issue.

This is not proof of anything, but certainly cause for extreme caution.

PeteGould Posted at 2015-6-22 13:56
I don't know either, but I DO know some of the stories involve starting with a 100% charge, flying, ...

I agree with Pete.   

My new approach is single fully charged battery = single long flight  as I don't want to take any chances.

jimhare Posted at 2015-6-22 11:35
Ed, is it okay to top up a battery if it's been unused for a while, or does it formally need to be  ...

No need to do the discharge.

Just connect the battery to the powersupply but as the battery might be over 95% you need to turn the battery ON to make the charging process start!

jimhare Posted at 2015-6-22 11:35
Ed, is it okay to top up a battery if it's been unused for a while, or does it formally need to be  ...

No need to do the discharge.

Just connect the battery to the powersupply but as the battery might be over 95% you need to turn the battery ON to make the charging process start!

I started a related thread yesterday: Battery Readings  I've noticed that, if I land the battery at 30% and let the battery sit turned off overnight, it's at 0%-4% and approx. 3.75-3.78V the very next morning.  This happens with all my batteries.  Looks like it is discharging automatically overnight.  Is this be design?  All of my batteries hold a full charge for at least a few days when charged (I haven't gone more than a few days without flying so far).

GravityStorm Posted at 2015-6-22 21:19
I started a related thread yesterday: Battery Readings  I've noticed that, if I land the battery at  ...

Both my TB47 batteries experience the same discharging effect that you described. Since i don't like having my lipos discharge down to critical levels and stored, except for calibration, what i do is that after i finish my flights and the batteries have cooled down, when i get home, i charge them back up to around 50-60% level. I then leave them as is and top them up to 100% before i take them out for next flight.

frank320 Posted at 2015-6-22 21:29
Both my TB47 batteries experience the same discharging effect that you described. Since i don't li ...

That's great advice, thanks.  I think I'll start doing the same.  Miketeel: I'm sorry about the loss of your Inspire in the bay.  That must have been painful to watch.  Hopefully you recovered it and can submit the logs to DJI.
EDIT:  I haven't seen them drop below 3.75V per cell so far at 0% so hopefully that's a good sign.

jimhare Posted at 2015-6-22 11:35
Ed, is it okay to top up a battery if it's been unused for a while, or does it formally need to be  ...

Jim,

The manual infers that you can re-charge without fully discharging, as the procedure is to switch on the battery if over 95% charge remains.

I have asked this question also in  the past and no doubt you like me have read many posts on the forum about this subject.  I think it is definitely wise to just use battery down as low as possible then re-charge, my question is if the manual says 5% as the benchmark if the battery is 1% or anything below the 5% is this enough to accept the percentage as being fully discharged, or does like many have said on the forum and also mentioned in the manual, it needs to physically switch itself off.

At the minute reading the manual both options are a valid and it seems valid to simply recharge the battery if not at 100% pre-flight and just do a full discharge after the 10 cycles.

I purchased one of these for my phantom 3 and my inspire when I had it.     If I plan on any water routes, I secure it to the landing gear.      http://www.amazon.com/gp/product ... _detailpage_o04_s00
at least I'd be able to find something if the water is less than 100 feet.

Interesting.

My guess here is that DJI is doing something in the battery to count the mah being burned during flights and that the partial flights are breaking / glitching the mah accumulation. With typical FPV / telemetry you'd just use the voltage. On a 6s battery you want to be hitting the ground when the unloaded battery voltage is about 22.8v.

jimhare Posted at 2015-6-22 11:35
Ed, is it okay to top up a battery if it's been unused for a while, or does it formally need to be  ...

I do.  Sometimes my Inspire in Tahoe will sit for 2-3 weeks depending on my schedule in Las Vegas.  I pull the batteries out and top them off before I fly.  Now I have flow for a time, powered down to play with the App and then 10-15 minutes later taken off and flown again.  Note that my first level warning is at 30%.  When that happens I start to bring the Inspire in close to me.  That way I can land if there is an issue.  Also note that in weather lower than 32F/0C the batteries can discharge quite dramatically.  I don't know about if you were to fly and then wait an hour or more and want to fly on the same pack.  If  you are going to do that, I would not fly out over water or areas that I could not easily retrieve my craft if it did a forced landing.

Here's my experience with rechargables.    They often stay strong until the very last and then drop very rapidly.   I run them in game cameras and when they go, they go quick.   So when it comes to flying an RC aircraft.  Charge them up, run them to 30% and land.  If you are in a pinch and need to go lower, then make sure it's over land.  And be prepared to land quickly when they do plummit.    I head back at 40% and land at 30%.  That way, you are probably pretty safe.     What the expire needs and probably should be added to future builds is a battery reserve.    Have two on board or make the packs with a 5 minute failsafe.    I'd like to see the expire 2 with payload capabilities and extra battery.

InspirelessAggi Posted at 2015-6-22 22:06
I purchased one of these for my phantom 3 and my inspire when I had it.     If I plan on any water r ...

Missing the point of this, once its has submerged in the salt water I am assuming all is lost, except maybe the micro sd card.

Help me out, what value is in the salvage?

Tahoe_Ed Posted at 2015-6-22 11:33
I agree and that is our official position.  However, I would have OP contact DJI and send them the ...

Submitted a Support case yesterday, and received confirmation of receipt but no response yet asking to send flight log.

Heard back from DJI Support. They said they were sorry about my experience and encouraged me to call support staff to discuss options.

Hoping for some for some relief on replacement.

miketeel Posted at 2015-6-23 11:04
Missing the point of this, once its has submerged in the salt water I am assuming all is lost, exc ...

Not much salt water in Texas.  Regardless.  I want to find it.  I paid for it
Why would you take off over water with 52% battery?  That's what I'm missing

miketeel Posted at 2015-6-23 11:35
Heard back from DJI Support. They said they were sorry about my experience and encouraged me to call ...

I wish you luck.

InspirelessAggi Posted at 2015-6-23 06:42
Here's my experience with rechargables.    They often stay strong until the very last and then drop  ...

I completely agree that it be a great idea for the Inspire to have an option to add a small 500Mah or so reserve battery, so that if the main battery or any of the 6  cells drop to below critical, there is at least a back up power option. At this point, there are just a lot of unknowns about Lipo battery packs, not just DJI - look at Boeing's 787 Dreamliner's battery issues. The  company that best seems to have a good management on these batteries seem to be Tesla, the all electric car company. But even that is not without issues. It's just that too many variables could affect the performance of these lipo batteries - age, discharge rate, cold or hot weather environment, previous charge levels, calibration, operating temperature at start/middle/end of flight, etc...

Whoever can come up with a attachment backup battery solution that the public can purchase to attach to their Inspire/Phantoms/800/900/1000 series could stand to make a lot of money... unless of course DJI then sees the demand for the backup power supply and starts providing the solution for 1/2 the price.

InspirelessAggi Posted at 2015-6-22 22:06
I purchased one of these for my phantom 3 and my inspire when I had it.     If I plan on any water r ...

This seems like a fantastic idea !  Thanks.

Sorry for your loss.   That has got to be an agonizing moment.  One I wish to never experience.
But thanks to your post and others...
When I purchase my drone, I have learned from all my reading to......

1). I will ALWAYS launch only with a fully charged battery pack (100%) or less than 8 minutes flight time on the battery.

2). I will not fly over water if my battery pack falls to 60% during flight.

Cessna172 Posted at 2015-6-23 22:55
Sorry for your loss.   That has got to be an agonizing moment.  One I wish to never experience.
But  ...

I look to the experts; the designers of the equipment and when they say it is ok to fly it should be ok. A sudden drop from 33% to 8% is not ok nor is it normal

I get flying over water is the users risk.

miketeel- Sir, I'm sorry to hear about the drowned bird.

I'm originally from the Bay Area, actually a bit north, in Napa. I can only imagine how cool of a view you might get from the top of Diablo or, the other side the GG in Sausalito. Perhaps a quick launch off ol' Mt. Tamaulipas and head toward the coast line at sunset with the fog rolling...man, I must admit, I miss it sometimes. Anyhoo...

I couldn't agree with you more concerning "experts and designers". This thing never ceases to amaze me with it's issues. What cracks me up is, it's okay to fly over a lava field but, the sensors on the bottom get freaked out over water, flooring patterns, mismatched draperies, Donald Trumps hair, yadda, yadda, yadda. Perhaps there are too many features and simply, an unregisted static discharge within the camera assembly contacts, causes a false positive? Honestly, I don't know. But what I do know, $4k for a glitchy, yet supposedly, top of the food chain ariel platform, is a bit much.

Keep us posted, sir. I hope all works out in your favor.

-S.N.

Scotflieger Posted at 2015-6-21 18:26
NEVER, NEVER, NEVER launch without a fully charged battery.

There are too many reported cases like  ...

Does the advise to never fly without a full charge mean that one should either fly until a low charge warning or fully recharge the battery before using it again if a brief flight used only 10 t0 50% of the fully charged capacity? I understand the recommendation to always start with a fully charged battery and fully charge my batteries no more than 24 hours before I’ll use them. What I don’t understand is am I placing my Inspire 1 at risk by starting out with a fully charged battery, flying it briefly, landing with at least 50% of the charge and then take off again and flying until I get a low power warning. I have been doing this but I have never experience the sudden drop in power that others have experienced. Thanks folks.

Sorry for your loss Miketeel. I hope it all works out in the end.
A lot of good info on this thread.

PhillyFlyer Posted at 2015-8-28 18:47
Does the advise to never fly without a full charge mean that one should either fly until a low cha ...

The latter scenario will work provided that the battery starts with a fresh full charge provided there is not a great time gap between the short flights.  The problem comes when a couple of days have lapsed since the battery was charged.

I have had one scary experience where the battery was charged several days earlier. When inserted it had 97% charge, immediately after launch that dropped unnoticed to 65%, I flew for 6 mins and got the 30% low battery warning which dropped immediately to 8% (critical). Having read the reports from others I land quickly from 35m and landed with 5% left.

miketeel Posted at 2015-6-26 14:21
I look to the experts; the designers of the equipment and when they say it is ok to fly it should  ...

Little to no salvage value, except you have flight data and an I1 to send back to DJI.  If you are a diver or know one, you may be able to locate your downed I1 based on the flight record on your tablet.  Most likely you will be told even if you recover it that the failure was a battery error and the battery should have been fully charged before flight and calibrated regularly.  Failure to do so would lead to this issue - pilot error.   

If you have square trade from Amazon, they would replace it if you have something to send in.  

I was more interested why your profile picture was taken in the produce aisle of a grocery store, but I get easily distracted by such things.  

Scotflieger Posted at 2015-8-28 16:37
The latter scenario will work provided that the battery starts with a fresh full charge provided t ...

Thanks Scotflieger, that helped me a lot to understand what I can do to avoid experiencing that sudden and unexpected drop in remaining power.

mixmaven Posted at 2015-8-29 21:50
Little to no salvage value, except you have flight data and an I1 to send back to DJI.  If you are  ...

I run a grocery chain in N. CA.
PS: DJI helped me out with a discount on a new machine.

jimhare Posted at 2015-6-21 22:35
Ed, is it okay to top up a battery if it's been unused for a while, or does it formally need to be  ...

I agree with Jim. What is the best method to discharge the battery?