Flight time with 4000mah and vision props?

[npalen]

I'm flying the FC40 which, as you probably know, is the 5.X MHz version of the 1.1.1. Have installed 2D gimbal with GoPro and genuine DJI Vision props. Mounted the 4000mah crosswise about mid ship. How much flying time should I expect from this setup? Will post what I'm getting later but don't want to influence estimates. Thanks in advance for any help and suggestions.

Edit: Would appreciate recommendations on gain settings also

 

[Ozzyguy]

I would estimate somewhere around the 17-20 mark. I get 17 mins from my stock 1.1.1 with no camera or anythhing else onboard.

 

[npalen]

What size battery and props?
Edit: I see you said "stock" so I would assume 2200mah and 8" props?

 

[Ozzyguy]

Battery is in my signature a 2700. Props are DJI 9 inch

 

[npalen]

Sorry, I missed that. Are you running prop guards?

 

[Ozzyguy]

No prop guards. I hand catch mine every flight as i was prone tipping on landing.

 

[ElGuano]

Hi npalen,

The biggest question is what is your AUW with the 4000 installed?

With an H3-2D and gopro and a typical 115-120mm long 4000mah, you're probably at around 1300-1325g? That combination should yield 13-15min flight time.

With 4400mah @ 1175g, I was getting about 16-17 minutes with the 9443.

 

[npalen]

OP here.
I was getting only about 8 minutes of flight with the 4000mah and P2 9" props. So I balanced them today (were not too badly out of balance) and removed the prop guards which were undersized for the larger props.
A test flight this evening gave 8 minutes to first warning and then the Phantom auto landed at about 11 minutes. Next step is go adjust the gains but needing some advice.
I did notice that the battery was not very warm upon landing so perhaps I need to readjust the alarm settings? Forgot to check the voltage after landing.

 

[npalen]

Hi npalen,

The biggest question is what is your AUW with the 4000 installed?

With an H3-2D and gopro and a typical 115-120mm long 4000mah, you're probably at around 1300-1325g? That combination should yield 13-15min flight time.

With 4400mah @ 1175g, I was getting about 16-17 minutes with the 9443.

I checked the AUW this evening and shows 1195 grams including the 300 gram battery weight. Something that might account for the low flight time I'm getting--when changing the battery connector to an XT60 I accidentally shorted the leads for a split second. Wondering if this may have damaged the battery? It charges up to 12.6 volts but I noticed that one cell was 0.03 volts lower than the other two which were 4.20 volts. Also, the green light on the charger never does come on even when fully charged. It alternates with the red light instead. Any way to "fix" this issue?

 

[ElGuano]

Hi npalen,

The biggest question is what is your AUW with the 4000 installed?

With an H3-2D and gopro and a typical 115-120mm long 4000mah, you're probably at around 1300-1325g? That combination should yield 13-15min flight time.

With 4400mah @ 1175g, I was getting about 16-17 minutes with the 9443.

I checked the AUW this evening and shows 1195 grams including the 300 gram battery weight. Something that might account for the low flight time I'm getting--when changing the battery connector to an XT60 I accidentally shorted the leads for a split second. Wondering if this may have damaged the battery? It charges up to 12.6 volts but I noticed that one cell was 0.03 volts lower than the other two which were 4.20 volts. Also, the green light on the charger never does come on even when fully charged. It alternates with the red light instead. Any way to "fix" this issue?

That's a good weight! The battery is lighter than I thought it would be. Back when I surveyed Hobbyking, there were no 4000mah batteries lighter than my 320g 3S2P. Nice to see things are changing.1200g @ 4000mah should get you in the ballpark of 15 minutes, depending on altitude, temperature, flying style, battery health, etc.

Shorting a battery is never good, even momentarily. I wouldn't worry too much about the 0.03v difference, especially with the cheapo DJI charger, but I would watch the cell voltages carefully for the next few flights, and make sure that it doesn't get any worse. People who have measured cells have reported consistently that even momentary shorts have resulted in measurable increases in the internal resistance of the battery (indicating they're damaged/have shorter life). That said, I've made quite a few batteries for my Phantom and the ones I've accidentally shorted are doing no worse than my "perfect" ones. They're all about 70-80 cycles in.

 

[Ozzyguy]

To maximize my flight time I use a cell checker/alarm attached to the outside of the battery door. My alarm is set to go off at 3.5 volts per cell.

 

[npalen]

I have one also and need to start using it again. Thanks for the reminder.

 

[npalen]

And thanks for all the input, guys. It's very much appreciated.

 

[BladHaund]

OP here.
I was getting only about 8 minutes of flight with the 4000mah and P2 9" props. So I balanced them today (were not too badly out of balance) and removed the prop guards which were undersized for the larger props.
A test flight this evening gave 8 minutes to first warning and then the Phantom auto landed at about 11 minutes. Next step is go adjust the gains but needing some advice.

The 4000 mAh is not doing the job you are expecting, if you get these times. I get the same times with a 2700 mAh, 9" XOXO knock-off props, gimbal and GoPro. And the lipo fits right in the compartment, no more modding necessary.

Also, if your bird is stable, you don't need to adjust the gains.