Battery performance in cold weather

[BaldEagle]

Just a few minutes ago, I flew for a bit. The temperature was 20 degree F, winds about 3mph (ground speed), sunny. I was flying low altitude, between 60-100 feet when battery warning came on at 30%. Started my descent ( bird was very close to GTH position) and I watched the battery percentage go from 30% to 1% within 3 minutes. When I landed, with motor off, it remained at 1%. Felt **** lucky I landed!

It seems like an awfully rapid decrease in battery reserve to go from 30% to 1% in 3 minutes. I am wondering if the cold had anything to do with it. I have also only been through one charging cycle.

For all of you highly experienced ones out there, please don't jump on me if it's an obvious issue. I'm in learning mode and sharing, hoping to learn and share experience.

I'm recharging and then hope to review the data. Any thoughts would be appreciated.

Thanks.

 

[Ultra310x]

I've seen a rapid decrease in battery as well i think the estimates are off

 

[shockwave199]

How off? If you can't trust remaining battery life you can't do anything much but fly it around for a little bit close by. Accurate battery life is a must or else you risk imminent crash.

 

[Diirk]

I had exactly the same issue today! I went from 20% to 0% in a matter of seconds! I almost crashed my inspire in the sea because of it. It was about 3 degrees celcius outside. This is a pretty major issue for me.

 

[Anticipate]

I made sure I put on the foam stickers they gave and it helped a lot. Only getting about 12 min in -5 C but no weird drops. And I have found the flight time estimate is totally inaccurate. It may be the time until the unit shuts off, but not the time you can actually fly. It will land well short of that.

 

[Helnet]

I noticed that the batteries I use in low temperature have an average loss of about 30%. Batteries are much more effective at 100% to 30%.

Also new batteries have a shorter duration.

It is better not to go lower than 30% without load. Otherwise the battery will degrade faster.

 

[shockwave199]

I understand that. But an inaccurate reading is a major thing. Either that, or it's need clarifying how this is correctly interpreted by the pilot.

 

[Paul K]

I usually fly in cold weather, and I didn't notice any drastic difference in battery duration. It depends how much current is drowned from a battery; if there is only a low current drawn from the battery, the battery stays cold and drains must faster, unless it is insulated or has some kind of heat jacket; a high current drawn from the battery warms itself up and doesn't drain as quickly. Other factors that need to be taken into consideration are, if the battery is warm during the transportation and how long it takes to warm up the craft and take off.

Could you confirm - did you use a fully charged battery and use it for that particular flight until it indicated that the batter was low?
- did you make a flight prior to the one, when the battery went low, without removing it from the craft?
- did you make a flight prior to the one, when the battery went low, remove and reinsert it into the craft, and make a second flight?

 

[Quadpilot]

Cold weather has a major effect on battery performance. As you are flying in cold weather, and assuming you plugged in a warm battery to start flying, that battery internal temperature gets colder as you fly through the air, decreasing it's performance and rapidly dropping the percentage of usable flying time. "Intelligent Battery" is an optimistic assessment, if not a misnomer, since it can only calculate based on the current conditions, and those change rapidly in an environment that is different than its initial state (i.e., temperature).

In addition, since it is most likely a new battery you are flying with, it has yet to be conditioned for optimum performance. Most lipos don't reach peak performance until they have been fully charged, then discharged to a fairly low state number of times. Please read the battery guidelines to find out more.

 

[Paul K]

My flight time in could wether (-5C) is only 15% shorter than in normal wether.The biggest loss is during the craft set-up initialization and beginning of the flight. My point is if the battery is drawing lots of current it gets warm by it self (you did notice yourself when you removed the battery after the flight it is warm/hot) As the photographer on another hand if I don't keep my camera in a worm place the battery will last only 50% of it own capacity.

 

[BaldEagle]

Could you confirm - did you use a fully charged battery and use it for that particular flight until it indicated that the batter was low?
- did you make a flight prior to the one, when the battery went low, without removing it from the craft?
- did you make a flight prior to the one, when the battery went low, remove and reinsert it into the craft, and make a second flight?

I started the flight at 69%. I had flown a bit earlier in the day and came back inside for a few hours. I assume the battery and craft were at room temperature when I went back out. But I do recall that when I started, the battery temperature read at 19 degrees.

I had only charged the battery once through (charged it when received it, discharged it flying, and charged it once again).
Maybe if I have waited a few more charge cycles before trying a fresh battery in the cold, I might not have experienced this.
It's 24 degrees today. I will be trying again later today. I'm going to hover the aircraft a few feet above ground level and see how long it will stay aloft.

 

[Funnone]

Just hovering is not going to be a good measurement of real time flying

 

[Mike Meyer]

This forum is great. I have yet to receive my Inspire...I have Phantom Vision Plus and Phantom/GoPro/Futaba kit as well...I am learning so many subtle and not-so-subtle tips about the Inspire that would never be included in any manual. Thanks to all.

 

[BaldEagle]

Just hovering is not going to be a good measurement of real time flying

I know. But I'm a little nervous. I just want to see if, coming to 30% battery life, I get a similar experience again with a nonlinear (in time) decrease in battery life. If I do not, I will graduate myself upwards to more realistic flying experiences. During this time, with only one battery, I am also conditioning the battery so I may solve the problem that way. Not a randomized controlled trial, but with $3000 in the air and being a bit of a worry-wort, I'm going to take it slow until I feel more confident. We have 3 more months of cold weather out here. Want to feel confident in the cold.

 

[Paul K]

BoldEagle this is the answer I was expecting:
With Phantom 1 the issue wasn't present, but with the P2 (smart battery) the following happened to me.
First I noticed it when flying for about 3 min and noticed strong wind gusts, for safety I terminated the flight with about 95% of power left .
I removed the battery and when I got back home ,I tried to charge it ,but the charger didn't engage.Next day I went for a short flight and I used the same battery(95% capacity left) , when I took off, a telemetry was indicating 94% , luckily I was watching battery level closely and 30 seconds later it showed 10.7V and low battery warning (I just had enough time to land safely).
I did several more tests with previously removed and reinstalled battery with the same results.
My conclusion is, that the problem is not the battery itself ,but the electronics controlling the battery levels.

My solution to this is to fully charge the battery just before flight ,and I also bought a "SINE WAVE" inverter ,and if unable to charge the battery at home ,I can charge it (or finish charging) while driving to the location...