Inspire 2 battery and duration tests

fredz · Jan 5, 2017

Did some I2 testing without cam/gimbal (not delivered yet)...

Some full throttle in GPS and Atti, some hovering, very little Sports mode.
Outside temp 4 deg Celsius.
Wind speed 5 m/s
20 m/s against wind, all modes
30 m/s atti and sports 26 m/s gps with the wind
Battery to 10%: 15:35
Second test, a bit warmer (8° C), but very windy (gusts of up to 50 mph): duration to 10% 20 minutes

Hovering test inside to 10% at 20 deg Celsius: 26:08 mins

Seems to me that because the batteries are "open to the air" at almost all sides, it performs very badly in cold weather.

15 or even 20 minutes flying doesn't seem long to me...

As for distance, 3 km without any problem.

The Editor · Jan 5, 2017

fredz said:
Did some I2 testing without cam/gimbal (not delivered yet)...

Some full throttle in GPS and Atti, some hovering, very little Sports mode.
Outside temp 4 deg Celsius.
Wind speed 5 m/s
20 m/s against wind, all modes
30 m/s atti and sports 26 m/s gps with the wind
Battery to 10%: 15:35
Second test, a bit warmer (8° C), but very windy (gusts of up to 50 mph): duration to 10% 20 minutes

Hovering test inside to 10% at 20 deg Celsius: 26:08 mins

Seems to me that because the batteries are "open to the air" at almost all sides, it performs very badly in cold weather.

15 or even 20 minutes flying doesn't seem long to me...

As for distance, 3 km without any problem.

I also wouldn't fly down to 10% (unless you want to lose your I2 prematurely)
Indicated 10% is very close to the plateau threshold where a Lipo will suddenly plummet.
As proved previously, DJI algorithms are not that great when it comes to fuel guage estimations so I would advise flying by cell/pack voltage which is absolute and not guesstimated by some Chinese software!
Your bird though, so your choice.

Quadpilot · Jan 5, 2017

Agree with The Editor, but for another reason. Flying new lipos down to 10 percent is a recipe for shorting their lifespan. DJI Forum Support recommends breaking in those lipos by flying them down to no lower than 50% for about the first 10 flights. This breaks them in gently and allows the circuitry to find a true 100% charge. YMMV

droneseyeview · Jan 5, 2017

Once the batteries have been cycled a few times you will notice longer flight times. Temperature is of course a factor but as long as the battery core temp is at least 20° C then the temperature won't be changing the flight time very noticeably.

Sent from my iPad using InspirePilots

Maverik · Jan 5, 2017

The Editor said:
I also wouldn't fly down to 10% (unless you want to lose your I2 prematurely)
Indicated 10% is very close to the plateau threshold where a Lipo will suddenly plummet.
As proved previously, DJI algorithms are not that great when it comes to fuel guage estimations so I would advise flying by cell/pack voltage which is absolute and not guesstimated by some Chinese software!
Your bird though, so your choice.

This is a good point.. What Cell Voltage would be appropriate then to end the flight? 3.6v?

Viper Pilot · Jan 5, 2017

That would work!

Florida Drone Supply · Jan 5, 2017

I have been waiting for some windy weather to do a real good wind performance test - and now its calm here in FL. The weekend looks like it will bring some wind, but I was curious to know how your I2 did in the 50mph gusts.

Thanks!

The Editor · Jan 6, 2017

Maverik said:
This is a good point.. What Cell Voltage would be appropriate then to end the flight? 3.6v?

3.5v per cell or even 3.45v is fine under load. Once landed, the pack will rebound 200mv or so to around 3.7v per cell which is fine.

Mark Taylor · Jan 6, 2017

Did you fit the battery insulation sheets that DJI supply in the box for cold weather flying?

Hellohogo · Jan 6, 2017

fredz said:
Did some I2 testing without cam/gimbal (not delivered yet)...

Some full throttle in GPS and Atti, some hovering, very little Sports mode.
Outside temp 4 deg Celsius.
Wind speed 5 m/s
20 m/s against wind, all modes
30 m/s atti and sports 26 m/s gps with the wind
Battery to 10%: 15:35
Second test, a bit warmer (8° C), but very windy (gusts of up to 50 mph): duration to 10% 20 minutes

Hovering test inside to 10% at 20 deg Celsius: 26:08 mins

Seems to me that because the batteries are "open to the air" at almost all sides, it performs very badly in cold weather.

15 or even 20 minutes flying doesn't seem long to me...

As for distance, 3 km without any problem.

Did you activate the warming feature or no?

arcticdronepilot · Mar 8, 2017

I've been flying above the Arctic Circle in Alaska, ambient air temp -15 to -20F, wind averaging 10-15 mph. I have seen flight times up as high as 18 minutes, and that is running the battery down no lower than 25%. No major maneuvers or high speed flying.

I tried the DJI "battery insulator" but they were a joke, I've sense designed my own clip on battery covers that make a big difference in temp. Will post a photo if anyone is interested.

My question - The landing gear consistently freezes and won't operate below even 15F sometimes warmer. Has anyone else experienced this? I wonder if the grease could be swapped for something low temp rated.

EDDSkitz · Mar 8, 2017

arcticdronepilot said:
I've been flying above the Arctic Circle in Alaska, ambient air temp -15 to -20F, wind averaging 10-15 mph. I have seen flight times up as high as 18 minutes, and that is running the battery down no lower than 25%. No major maneuvers or high speed flying.

I tried the DJI "battery insulator" but they were a joke, I've sense designed my own clip on battery covers that make a big difference in temp. Will post a photo if anyone is interested.

My question - The landing gear consistently freezes and won't operate below even 15F sometimes warmer. Has anyone else experienced this? I wonder if the grease could be swapped for something low temp rated.

I'd like to see that setup...

And not sure it would be the grease holding you up there, but you could absolutely change it so long as it's plastic safe.

The motor for the gear is actually all the way on the bottom and totally exposed, wonder if taping a hand warmer below it would help...

arcticdronepilot · Mar 8, 2017

EDDSkitz said:
I'd like to see that setup...

And not sure it would be the grease holding you up there, but you could absolutely change it so long as it's plastic safe.

The motor for the gear is actually all the way on the bottom and totally exposed, wonder if taping a hand warmer below it would help...

I'll post a picture when i'm back in civilization. And look closer at the motor to see if it can be shielded.

Florida Drone Supply · Mar 9, 2017

arcticdronepilot said:
I've been flying above the Arctic Circle in Alaska, ambient air temp -15 to -20F, wind averaging 10-15 mph. I have seen flight times up as high as 18 minutes, and that is running the battery down no lower than 25%. No major maneuvers or high speed flying.

I tried the DJI "battery insulator" but they were a joke, I've sense designed my own clip on battery covers that make a big difference in temp. Will post a photo if anyone is interested.

My question - The landing gear consistently freezes and won't operate below even 15F sometimes warmer. Has anyone else experienced this? I wonder if the grease could be swapped for something low temp rated.

+1 for being interested in seeing a photo when you have a chance.

Thanks!

arcticdronepilot · Mar 14, 2017

Here's a photo showing the battery covers in use. This was actually a test to show the difference with/without, ambient air temperature was relatively high around 20f. I've done about two dozen flights with them now and they work great. As I said I was getting 15-18minute flights at -20 to -30 while flying in a 10-15 mph wind. After flights the batteries were even warm to the touch when I removed the covers so they did a good job of holding in heat.

If you are interested in the covers I've just made them available at www.cinetulz.com.

For the iPad this is the first design of a cover/holder that provides space for 2x hand warmers and clips even more securely into the remote control. Testing this week.

And the final bit is landing gear - mine freezes up and refuses to work at about 10f and below. The drive motor is exposed so another test will happen with this cover design.