Severe battery % loss during flight

TAMedia · Feb 26, 2015

Hello, last night I decided to attempt some night pictures. It was 14 degrees, fairly calm wild conditions, and i was 9 mixtures into the flight. Everything was working correctly and i was getting some great pics until the battery got to 41%. It suddenly went from 41% to 8% in 2 seconds, the landing gear started to lower and my heart rate jumped, lol. I was over 200 ft high and a few hundred feet out. I was able to get it back and land it, so theres nothing happened to the bird, but would just flying in the cold create that dramatic % drop?

Method007 · Feb 26, 2015

Yes, it can. Lipo's are quite sensitive to temperature.

Funnone · Feb 26, 2015

yeah I had the same thing happened about a month ago was at 34% decided to come in to land, about 6 feet off the ground low battery warning ⚠ 30% no big deal, 3 seconds later, critical battery warning 5%. landed without incident temperature outside around 29 degrees with a 8 mph wind.
Like meth said “Lipo's are quite sensitive to temperature.”
I see your in toledo also.

TAMedia · Feb 26, 2015

Ya I knew they were sensitive to cold, but I've never had a % drop like that before, pretty crazy. Thx for the replies guys

catware · Feb 26, 2015

I had a similar drop with one of my Phantom 2 batteries, from 25% to 4% in a couple seconds, but this was in 75 deg weather. The next flight with this battery, when it reached 85% (from a full charge) it dropped down to 10% in just a few seconds. I determined it was a faulty battery and I had it replaced under warranty. The battery had 27 flights on it at the time.

So maybe it's related to the cold, but I'm surprised that it dropped so quickly nonetheless.

This is from an RC battery manufacturer's specs, "Lipo batteries will experience a 30% temporary decrease in capacity at temperatures below 32 deg F. Flying in extreme cold weather should be done with great care. Never expose them to temp. below -4 deg F."

jon b · Feb 26, 2015

Absolutely makes sense. The chemistry in Lipo batts are pretty sensitive to cold, especially if they are directly exposed. Phantoms actually fare better since their small lipos ride inside but still, when the temps drop down you have to be very careful. I took an S800 out the other day and saw the same kind of thing. A 10K MAH batt couldn't muster better than a few minutes in the air.

Heard talk of battery warmers on this forum and scoffed but maybe it's worth the draw to insulate the cells?

My fingers get too cold to get into much winter flying anyway

RossF · Feb 26, 2015

Has this happened before with the same batteries at the same temps? I have been flying a lot in 10 - 20 degrees fahrenheit weather in Chicago. Sometimes over a lake, I bring my inspire back around 30% always but have never experienced a battery drop. I was thinking I "trust"it now but I feel a little nervous again after reading this.

jon b · Feb 26, 2015

What I was posting was with my experience with a heavy lift rig. Haven't ventured out with the inspire at low temps yet

Oh and battery warmer... Looked again and don't see that helping much. Insulation is what's needed. Or better weather!

Kilrah · Feb 27, 2015

Again when you see that issue please look at the battery info page for total and cell voltages and if possible get a screenshot, while still in the air (obviously 5cm above ground just before landing).
Seen many reports of that issue but unfortunately absolutely nobody thought about looking at the rich data we have at hand to actually try and understand what the problem is.

The Editor · Feb 27, 2015

Kilrah said:
Again when you see that issue please look at the battery info page for total and cell voltages and if possible get a screenshot, while still in the air (obviously 5cm above ground just before landing).
Seen many reports of that issue but unfortunately absolutely nobody thought about looking at the rich data we have at hand to actually try and understand what the problem is.

+1

The Inspire App gives you good real time info on mAh left (and therefore consumed) as well as individual cell voltages down to 0.1v and battery temp. During flight I regularly flick into this page just for a visual indication of what's going on. You are able to see instantly whether there is a large imbalance between cells under load and therefore avert a potential problem.

As an aside... ALL Batteries no matter what their chemical makeup perform less efficiently in lower temperatures. If you are flying at below freezing temperatures expect your packs to perform at anything up to 50% less than in warm temperatures. Although in reality it may not be that severe a reduction it does not hurt to ere on the side of caution. This means if you usually get 15 minutes out of your pack, think about bringing the Inspire back to you (and certainly away from water) after about 7 or 8 minutes. Cold temperatures means your cells will not give up their charge as easily under load and may not perform as expected when a demand is put on them..... Be warned people.

Quadpilot · Feb 27, 2015

Echoing the above comments by @The Editor and @Kilrah, it's important to keep the batteries as warm as possible in flights when the temps are low. Keeping the batteries warm before flight is only half the battle. During flight, insulation is the only solution. I have five batteries and only one set of battery insulators provided by DJI, so I made replacements for the battery insulation out of 1/8 in neoprene sheets with a sticky adhesive. I also made a battery compartment wrap with 1/4 in neoprene sticky that wraps around the outside of the battery compartment. I have had good results in 0-10 deg F (minus 18- minus 12 C), with the battery temp at app 20 C at the end of a 10 minute flight. Speed and altitude (and wind) have some bearing on the temp loss during flight, obviously.The attached images show my stickies and wrap (just use the supplied battery stickies from DJI as a template).

The neoprene sheets can be purchased on amazon: http://www.amazon.com/gp/product/B001GAD5G4/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Granted, I'll have enough neoprene that it'll last for years, but the stuff works for me.

jon b · Feb 27, 2015

Quadpilot said:
Echoing the above comments by @The Editor and @Kilrah, it's important to keep the batteries as warm as possible in flights when the temps are low. Keeping the batteries warm before flight is only half the battle. During flight, insulation is the only solution. I have five batteries and only one set of battery insulators provided by DJI, so I made replacements for the battery insulation out of 1/8 in neoprene sheets with a sticky adhesive. I also made a battery compartment wrap with 1/4 in neoprene sticky that wraps around the outside of the battery compartment. I have had good results in 0-10 deg F (minus 18- minus 12 C), with the battery temp at app 20 C at the end of a 10 minute flight. Speed and altitude (and wind) have some bearing on the temp loss during flight, obviously.The attached images show my stickies and wrap (just use the supplied battery stickies from DJI as a template).

The neoprene sheets can be purchased on amazon: http://www.amazon.com/gp/product/B001GAD5G4/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Granted, I'll have enough neoprene that it'll last for years, but the stuff works for me.
View attachment 610 View attachment 611

Yep, that's gonna help a lot and thanks for the source of sticky backed neoprene

Mazz · Feb 27, 2015

Ya I have been using the battery "covers" for temperature ever since I started flying my I1. It has repeatedly been in the negatives and despite knowing I probably shouldn't fly in -15 degree F sometimes you just have to (usually I just want to fly). I actually did experience a funny battery situation similar to this but that was around when I got the inspire in round 1. It will certainly fly cold though I can attest to that. No issues since then.

I'm curious, were your batteries room temp to start with? Were they very cold when you brought them in?

mechanicus · Nov 30, 2015

I experienced exactly the same problem. It was 7degrees above zero so not really cold. I did not make any strange move. The inspire was hanging still in the air when suddenly my power dropped from 51% to 4% within less than a second. I scared the hell out of me. Having the X5 hanging under the inspire this makes me insecure to fly. I returned the batteries to the dealer and I get a full replacement from DJI with the garanty that my problem is solved. In other words it's not going to happen again. Fingers crossed.

Check 1'58" for the magic to happen

The Editor · Nov 30, 2015

mechanicus said:
In other words it's not going to happen again.

It will if you start your flights without a fully charged pack each time!

mechanicus · Nov 30, 2015

So I can't fly move location and fly again if I don't charge up to a 100% in the meanwhile? That's bollux.

I charged a day before and somehow it dropped (within a night) to 63%
I say bad product (or at least firmware), in any case this should not be happening and makes the whole thing dangerous. You have to agree on that. Imagine trying to get the quad back and you don't make it home. The damage it could make!!

I purchase a pretty expensive machine, expensive lens and a few expensive batteries. I expect some guarantee I won't fall from the sky. At least not without me telling it too.

crashburn · Nov 30, 2015

mechanicus said:
I experienced exactly the same problem. It was 7degrees above zero so not really cold. I did not make any strange move. The inspire was hanging still in the air when suddenly my power dropped from 51% to 4% within less than a second. I scared the hell out of me. Having the X5 hanging under the inspire this makes me insecure to fly. I returned the batteries to the dealer and I get a full replacement from DJI with the garanty that my problem is solved. In other words it's not going to happen again. Fingers crossed.

Check 1'58" for the magic to happen

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I had sudden battery drop, from 45 to 1%, with a 100% charged battery, and autoland while about 800 feet from home, so BEWARE.

The Editor said:
It will if you start your flights without a fully charged pack each time!

Shemp · Feb 2, 2016

catware said:
I had a similar drop with one of my Phantom 2 batteries, from 25% to 4% in a couple seconds, but this was in 75 deg weather. The next flight with this battery, when it reached 85% (from a full charge) it dropped down to 10% in just a few seconds. I determined it was a faulty battery and I had it replaced under warranty. The battery had 27 flights on it at the time.

So maybe it's related to the cold, but I'm surprised that it dropped so quickly nonetheless.

This is from an RC battery manufacturer's specs, "Lipo batteries will experience a 30% temporary decrease in capacity at temperatures below 32 deg F. Flying in extreme cold weather should be done with great care. Never expose them to temp. below -4 deg F."

What's the warranty on the 47's?

creativedogmedia · Feb 2, 2016

Quadpilot said:
Echoing the above comments by @The Editor and @Kilrah, it's important to keep the batteries as warm as possible in flights when the temps are low. Keeping the batteries warm before flight is only half the battle. During flight, insulation is the only solution. I have five batteries and only one set of battery insulators provided by DJI, so I made replacements for the battery insulation out of 1/8 in neoprene sheets with a sticky adhesive. I also made a battery compartment wrap with 1/4 in neoprene sticky that wraps around the outside of the battery compartment. I have had good results in 0-10 deg F (minus 18- minus 12 C), with the battery temp at app 20 C at the end of a 10 minute flight. Speed and altitude (and wind) have some bearing on the temp loss during flight, obviously.The attached images show my stickies and wrap (just use the supplied battery stickies from DJI as a template).

The neoprene sheets can be purchased on amazon: Amazon.com: Sponge Neoprene With Adhesive 1/8" Thick X 54" Wide X 1': Home Improvement

Granted, I'll have enough neoprene that it'll last for years, but the stuff works for me.
View attachment 610 View attachment 611