Dji F550 with aero craft gimbal drawing too much current.

[ROVguy]

Hey guys, maidened the hexa today. Didn't go well. The hexa was drawing way too much current. 30A @ half throttle. The independent lipo voltage alarm was going off as well. I've since checked the lipo it read 16v and 75% capacity! I was in the air less than a minute.

I'm running stock dji motors, esc's, 8" props and 4S 5000 mah lipo.
The gimbal servos are savox sh-0257mg connected direct to the Naza and the Naza is set to 400 hz. I'm assuming that is ok?

I really need some help with this.

 

[OneStopRC]

I had read somewhere this is not a good idea, some have said to use controllers for the servos. Some servos can overload the Naza and cause it to fail.... I am not 100% sure on this, but I am sure someone can pipe in and say.

 

[kloner]

im not sure those servos are 400hz...

if the gimble isn't balanced real well it'll run harder. But why do you think it's the gimbal. a rig as heavy as yours should be 30 amp hover. I'd try the 10" on 4s and i'd try to put a bec to power the gimbal

the early battery alarm indicates the pack has damage. what kinda charger you have? is the pack holding 4.20 a cell after charging?

 

[ROVguy]

I had read somewhere this is not a good idea, some have said to use controllers for the servos. Some servos can overload the Naza and cause it to fail.... I am not 100% sure on this, but I am sure someone can pipe in and say.

I've read this too, I'm looking to power the servos off a bec and just have the control signals coming from the Naza.

 

[ROVguy]

im not sure those servos are 400hz...

if the gimble isn't balanced real well it'll run harder. But why do you think it's the gimbal. a rig as heavy as yours should be 30 amp hover. I'd try the 10" on 4s and i'd try to put a bec to power the gimbal

the early battery alarm indicates the pack has damage. what kinda charger you have? is the pack holding 4.20 a cell after charging?

Hey kroner, I'm not sure about the frequency of the servos either I've not been able to find any detailed information on them. The gimbal does seem balanced, I will stick a pic of it up. I will give the lipos a full balanced charge and see how they look. View attachment 9740

 

[ROVguy]

Well I feel a fool. Ive now realised I had the EZOSD incorrectly set, I had it set to ALARM at 14.8V which given thats the 4S on load voltage isnt very good. The quick blast I gave it sunday was about 2 mins in the air and I used about 20-25% of the lipo on 8" props. Tonight I gingerly tested the Hexa on the table, IVe set the EZOSD to voltage monitor to AUTO and I held it down whilst giving it a blast in manual mode and monitored the voltage, at nearly max chat it dropped to about 14V and was drawing +35A. Im hoping to give it another go tomorrow and see how it fairs. Ive since ordered 10" props and 2x Gens Ace 3S 5500mah lipos.

Heres a vid of the HExa and Gimbal in action. The settings need tweaking.

http://www.youtube.com/watch?v=hBfp0AYYpXY

 

[ROVguy]

Here's another flight with 550 and gimbal

http://www.youtube.com/watch?v=wE_xP9r4rsc&sns=em

 

[ROVguy]

im not sure those servos are 400hz...

if the gimble isn't balanced real well it'll run harder. But why do you think it's the gimbal. a rig as heavy as yours should be 30 amp hover. I'd try the 10" on 4s and i'd try to put a bec to power the gimbal

the early battery alarm indicates the pack has damage. what kinda charger you have? is the pack holding 4.20 a cell after charging?

Hey kloner,

I've since found out the servos can run at 200Hz.




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[kloner]

i found out 333 is the max. i tried posting it, but lost this post.

 

[ROVguy]

Oh, nice one! Thanks Kloner. I'm all set up for 200hz and away out tomorrow for a flight, weather depending. Will change it after.

I'm looking forward to seeing if there's much of a difference switching over to 3S and 10" props.


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[ROVguy]

Well, that my test flight postponed for 4 weeks, it's been chucking it down all day and I'm back to work tomorrow :-(


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[AEA737]

Well I feel a fool. Ive now realised I had the EZOSD incorrectly set, I had it set to ALARM at 14.8V which given thats the 4S on load voltage isnt very good. The quick blast I gave it sunday was about 2 mins in the air and I used about 20-25% of the lipo on 8" props. Tonight I gingerly tested the Hexa on the table, IVe set the EZOSD to voltage monitor to AUTO and I held it down whilst giving it a blast in manual mode and monitored the voltage, at nearly max chat it dropped to about 14V and was drawing +35A. Im hoping to give it another go tomorrow and see how it fairs. Ive since ordered 10" props and 2x Gens Ace 3S 5500mah lipos.

I have also a heavy F550 with the same landing gear and gimbal plus FPV equipment. My experience is that it does not fly well on 3S lipos and the 10" Graupner props. It was running at +80% throttle just to hover, with very little room for error in case you need some extra power to save your hexa. It flies much better on 4S, more power to spare.

Javier