Forced landing due to "critically low battery"... At 46%!

Pescatoral Pursuit · Sep 16, 2016

Intended to fly about 2 weeks ago so charged my 5 batteries. Didn't happen and 2 weeks went by before an opportunity to fly again. In the meantime some batteries had begin to self discharge. No biggie. I was on the beach with the kids, and put the least charged battery in first, a tb47 with 39 charge cycles. Booted up and it came up around 60% which I figure is enough to reaquaint and dial in the camera.

Fly around close a little bit then do a run down the beach parallel to stretch her legs a bit. Barely into that and I get a "motility" warning which I iregard as because the winds are up around 15-20. Make a uturn to do a run past my girls who are walking along the shoreline and get a RTH warning immediately followed by a notification of a forced landing imminent so I dial the camera 90 deg down, adjust to miss a shrub and put down in the dune. camera shuts off and I walk the 100 yds to where the drone is. cant remember if i turned the battery back on but app is reading 46% so i pick it up, restart the motors, and launch it again. it flys w no other issues besides i think another low battery warning well above the 25% that i have programmed. Land it with about 20-22%. Although i have litchi, i used the dji go app to be a little more "secure." WTH!? i often fly, and could've very easily been over water and wouldve had drowned bird.

Any ideas on the problem? software? After an issue this past july 4th where the software saved the aircraft from a mishap well out over water, giving me supreme confidence in its survivability, that has all been taken away and will now have to be reestablished.

Edit: each cell within .01 voltage.

PortCanaveralFlorida · Sep 16, 2016

Pescatoral Pursuit said:
Intended to fly about 2 weeks ago so charged my 5 batteries. Didn't happen and 2 weeks went by before an opportunity to fly again. In the meantime some batteries had begin to self discharge. No biggie. I was on the beach with the kids, and put the least charged battery in first, a tb47 with 39 charge cycles. Booted up and it came up around 60% which I figure is enough to reaquaint and dial in the camera.

Fly around close a little bit then do a run down the beach parallel to stretch her legs a bit. Barely into that and I get a "motility" warning which I iregard as because the winds are up around 15-20. Make a uturn to do a run past my girls who are walking along the shoreline and get a RTH warning immediately followed by a notification of a forced landing imminent so I dial the camera 90 deg down, adjust to miss a shrub and put down in the dune. camera shuts off and I walk the 100 yds to where the drone is. cant remember if i turned the battery back on but app is reading 46% so i pick it up, restart the motors, and launch it again. it flys w no other issues besides i think another low battery warning well above the 25% that i have programmed. Land it with about 20-22%. Although i have litchi, i used the dji go app to be a little more "secure." WTH!? i often fly, and could've very easily been over water and wouldve had drowned bird.

Any ideas on the problem? software? After an issue this past july 4th where the software saved the aircraft from a mishap well out over water, giving me supreme confidence in its survivability, that has all been taken away and will now have to be reestablished.

Edit: each cell within .01 voltage.

Sup Otown!

I've had ONE flight like that. Lucky I didn't crap in my shorts

. From then on, I've always use my batteries within 24hrs after charging. Never flew on a 60, 50 precent batter at all, that sucker's going back on charge! A huge percentage of my flights are over water (long range) and I'm hopefull I'll not be coming here and saying... crap, my aircraft is at the bottom of the ocean!!!

AeroMirage · Sep 16, 2016

The longest I will let batteries set in my case is 2-3 days. After that, back into the smart powercharger they go for touchup.
I have read of many other's having close calls and even crashes from sudden voltage drop due to 'stale' batteries.

PortCanaveralFlorida · Sep 16, 2016

AeroMirage said:
The longest I will let batteries set in my case is 2-3 days. After that, back into the smart powercharger they go for touchup.
I have read of many other's having close calls and even crashes from sudden voltage drop due to 'stale' batteries.

Great word, "stale" batteries

Mad_angler1 · Sep 16, 2016

Simply never ever fly a battery that's began to self discharge or has been sitting for more than a 4-5 days, TBH over 48 is a absolute no no for me.

These packs don't reacts well when capacity is not 100% when they have been sitting, they loose their punch after a few days and if self discharge kicks in your into real danger zone.

Fly a freshly charged battery with in 24 hours only, if it's been sitting a few days put in in the craft for 10 minutes on the ground get a few % off it then put it back into charge to top it off again.

Alternatively just put it back into charge and turn the pack on but I prefer to take a few % out of it.

IrishSights · Sep 17, 2016

Pescatoral Pursuit said:
Intended to fly about 2 weeks ago so charged my 5 batteries. Didn't happen and 2 weeks went by before an opportunity to fly again. In the meantime some batteries had begin to self discharge. No biggie. I was on the beach with the kids, and put the least charged battery in first, a tb47 with 39 charge cycles. Booted up and it came up around 60% which I figure is enough to reaquaint and dial in the camera.

Fly around close a little bit then do a run down the beach parallel to stretch her legs a bit. Barely into that and I get a "motility" warning which I iregard as because the winds are up around 15-20. Make a uturn to do a run past my girls who are walking along the shoreline and get a RTH warning immediately followed by a notification of a forced landing imminent so I dial the camera 90 deg down, adjust to miss a shrub and put down in the dune. camera shuts off and I walk the 100 yds to where the drone is. cant remember if i turned the battery back on but app is reading 46% so i pick it up, restart the motors, and launch it again. it flys w no other issues besides i think another low battery warning well above the 25% that i have programmed. Land it with about 20-22%. Although i have litchi, i used the dji go app to be a little more "secure." WTH!? i often fly, and could've very easily been over water and wouldve had drowned bird.

Any ideas on the problem? software? After an issue this past july 4th where the software saved the aircraft from a mishap well out over water, giving me supreme confidence in its survivability, that has all been taken away and will now have to be reestablished.

Edit: each cell within .01 voltage.

So just that I understand this right...you flew with partially self discharged batteries, got a motility warning, which you ignored, flew close to your kids in that state, went through a forced landing, restarted the the Inspire and flew some more!! You then get another low battery warning and continue to fly to 22% or so. And you ask for ideas to the problem?

PFAW Holder
BNUC-S Qualified

Aviator · Sep 17, 2016

I always, always, always charge my batteries immediately before flying them!
Even if they have recently been fully charged, if I put them back on charge and no lights come on, I switch the battery on to force a recharge.

The Editor · Sep 17, 2016

Aviator said:
I always, always, always charge my batteries immediately before flying them!
Even if they have recently been fully charged, if I put them back on charge and no lights come on, I switch the battery on to force a recharge.

That could be me saying that! ^^^^^^^

Mad_angler1 · Sep 17, 2016

IrishSights said:
So just that I understand this right...you flew with partially self discharged batteries, got a motility warning, which you ignored, flew close to your kids in that state, went through a forced landing, restarted the the Inspire and flew some more!! You then get another low battery warning and continue to fly to 22% or so. And you ask for ideas to the problem?

PFAW Holder
BNUC-S Qualified

I was trying not to be critical lol but that's what I wrote the first time pretty much.

Pescatoral Pursuit · Sep 17, 2016

IrishSights said:
So just that I understand this right...you flew with partially self discharged batteries, got a motility warning, which you ignored, flew close to your kids in that state, went through a forced landing, restarted the the Inspire and flew some more!! You then get another low battery warning and continue to fly to 22% or so. And you ask for ideas to the problem?

PFAW Holder
BNUC-S Qualified

I would say "don't be a horse's ***" but that is clearly your intention.

Mad_angler1 said:
I was trying not to be critical lol but that's what I wrote the first time pretty much.

Uh no, you offered sound advice directly related to the situation the "first time" and I appreciate it, it makes sense, and I'll heed to it. That's what these forums are for though there are some who use them to bolster their self esteem by twisting what is posted because it's the only way they can feel good about themselves. There's always more than a few in every crowd.

IrishSights · Sep 17, 2016

You should read the forum rules about name calling. I'm not the one who ignored the warnings and put your kids in danger. Enough said.

PFAW Holder
BNUC-S Qualified

Pescatoral Pursuit · Sep 17, 2016

IrishSights said:
You should read the forum rules about name calling. I'm not the one who ignored the warnings and put your kids in danger. Enough said.

PFAW Holder
BNUC-S Qualified

I didn't ignore any warnings and no one was in danger at any time, but if the horseshoe fits...

You should volunteer for a charity so you don't have to fabricate stories that denigrate others in order to bolster your self esteem...

lake_flyer · Sep 17, 2016

Pescatoral Pursuit said:
I would say "don't be a horse's ***" but that is clearly your intention.

I understand Irish Sights completely. It sounds hard but he's right. It's difficult to hold back and not to write what he wrote. I was thinking about writing that down when I noticed he already did.

But don't blame us, the certified ones, we run in fact an aviation company, nothing less.

It's exactly what professional UAV training does to any person. You become extremely aware of any probability of risk. It's all about mitigation. If you were mitigating the possible risks you wouldn't have flown in the first place.

Still, good to discuss this. You will never do that again and I hope others reading this will learn from it.
Good that you shared it. For that you deserve a thump up. Although it has been discussed many times, it still is the no1 reason Inspires fall out of the sky or autoland in the ocean.

That's why I made floats

(literally, my heart beat is a lot slower now when flying over the water)

Pescatoral Pursuit · Sep 17, 2016

lake_flyer said:
I understand Irish Sights completely. It sounds hard but he's right. It's difficult to hold back and not to write what he wrote. I was thinking about writing that down when I noticed he already did.

Oh look another one right on que... Soon dennis r will be along to make a false accusation that I was doing it for profit. You guys must travel in packs but then circle-jerks require that, no?

Pescatoral Pursuit · Sep 17, 2016

Sincere thanks to the guys who make this forum a benefit to the community by simply offering proper advice directly related to the scenario, rather than taking the opportunity to engage in schoolgirl drama.

lake_flyer · Sep 17, 2016

Pescatoral Pursuit said:
Oh look another one right on que... Soon dennis r will be along to make a false accusation that I was doing it for profit. You guys must travel in packs but then circle-jerks require that, no?

What exactly is a circle-jerk? I could name you a couple a really good Dutch names but that would be pointless I guess.

Ah wait, found it:

circle jerk
1.) When a group of males sit in a circle, ......fill in the rest.

Disgusting, click the link, only if you're not easily offended. We have no words for that kind of behaviour in the Netherlands. Perhaps because we seldom sit in circles here

Some American friends use an amazing vocabulary, derived from the gutter.

But I trust you meant the 3rd definition given there........

Wow, how can I get rid of that image in my head now

Pescatoral Pursuit · Sep 17, 2016

lake_flyer said:
Wow, how can I get rid of that image in my head now

Wrong circle jerk but you get the point. You would better serve yourself and this forum by not engaging in it.

lake_flyer · Sep 17, 2016

Pescatoral Pursuit said:
Wrong circle jerk but you get the point. You would better serve yourself and this forum by not engaging in it.

Get yourself another hobby pal. Your not up to it.

IrishSights · Sep 17, 2016

Personal attacks on here are not tolerated. All the personal jibs don't change the facts. I was relaying the facts in the OP. Based on what you have told us, the is no hardware or software problem. It is pure pilot error, hard I know that is to swallow. We have all made pilot errors, even certified operators. It's about learning so everyone can benefit from the OP. It's a bit sad when advice is asked for as in the OP and it is not received but instead turns to name calling.

Time to end this post I think Mr @Editor

Holder of CAA PFAW
BNUS-S Certified Pilot

Pescatoral Pursuit · Sep 17, 2016

So it would seem that without any recent activity, (charging, discharging,) that the voltage reading is for a "resting" battery and it is incapable of providing any significant demand regardless of stated capacity until the "juices start flowing" again by stimulating (energizing) the battery compound via charging/ discharging. This would explain the difference in battery reading and output. So now I can assume that the battery does not actually contain, or able to readily supply, the amount of available energy shown, unless it has been activated or energized by recent current fluctuation either way, and the concensus appears to be 24 to 48 hours until the battery compound begins to "rest" again. This would explain why, 5 or so minutes after the forced landing due to an inability to extract the energy from a battery that clearly listed an ample amount, that it started up, and flew again for the remainder of the cycle, though admittedly not as much demand was placed on it afterwards as it was "walked" back to the launch point.

There were 2 other batteries in a state of self-discharge that were used afterwards with only "light" control inputs and flew/ hovered without incident or warning.