pixhawk 2.1 with jeti spin pro 300 and tmotor u15 no spin up

Hi all, I am new to the forum and about 2 months into a rather large x8 copter. I flew a flamewheel quad to get myself familiar with the mission planner and general drone flying, as i am a fixed wing pilot of 20+ years. Has anyone run a large jeti spin pro (mine is a 300 mated to a T-Motor U-15) esc through a pixhawk 2? I can arm the flight controller but cant get any reaction from motors. No initial beeping or anything. I did calibrate the esc's individually with the recomended radio style calibration, and it all worked fine. Once plugged into the PH2, nothing. Only running 4 motors just to test spin motors for now. Planning to start a small scale version to configure x8 in PH, but I would like to figure out this issue quickly, trying to fly the big guy in a couple of weeks when the fuse is completed. Wondering if i need the jeti box to configure esc's properly to work with PH2, or some other setup is wrong. I do have a pretty long run of wire from the PH2 to the esc (4' to front 6' to rear), wondering if i need (or can) step up signal voltage to esc due to voltage drop. I am running 14awg servo leads to try to combat this. Any help would be appreciated as i am a wrench user instead of a keyboard user (no programming experience). Thanks in advance.

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More info...

 -running two 16000mah 6s packs in series for test flying on each esc/motor combo. so 12s

 -40" T-Motor props

 -spektrum dx6 gen2 radio for now, dx8 gen2 in the works

 -using a satelite rx for now, will end up with telemetry system, and fly without a rc transmitter at some point

 -separate power supply for PH2

Have you disabled pre-armed checks ? also what firmwear is your ESC running yes you will need to configure your ESC properly? 

Thanks for the reply OG, but we figured it out last night. Rereading setup, and some other blogs, the servo rail isnt powered... the jeti esc's need to see 5 volts to run. Everything is running like it should now, and boy what a noise these big motors make! Now my question is, what is the best (most reliable) way to power the rail? We just pugged a BEC'd lead into the rail. I will need a all 8 outputs monday when I run all 8 motors...


If the pixhawk 2.1 is the same as the original pixhawk, then all you should need is a single BEC plugged into any spot on the servo rail in order to power the opto-isolators on the ESCs. If I remember correctly, the main difference between the 1 and 2.1 is that on the pixhawk 1 powering the servo rail will also act as a backup power supply to the autopilot, while on the 2.1 the servo rail is not connected to the auto pilot's power supply. If that is the case, then I would look at using 2 mauch modules to power the auto pilot, and another high quality BEC to power the servo rail and ESC opto isolators.

Out of curiosity, what payload are you flying that uses a 40" prop? I have an X8 with 30" props that we use for aerial spraying, and it is quite a beast, I can only imagine what a 40" prop must be like!



Thanks Brian,
I will be powering the autopilot with 2 separate battery packs, and now that I know about the servo rail, a separate pack for that. I cant go into the details of the x8 we are building yet, but soon I may be able to. I will just say that it will carry around 200lbs. Should be putting power to the props within a week, should be interesting!

Sounds like quite a monster. I would love to see pictures if you are able to share.



Wow, that will be a monster machine. Are you talking about a 200 lb. payload or gross vehicle weight? If you are talking 200 lb. payload it will be under powered. I figure your motors ,esc's, and 12 s battery for each motor will weigh ~ 100 lbs. 300 lbs. puts you at ~ 70% power and we haven't even included the frame weight. Any thing above 70% hover power is dangerous because there is not enough reserve for maneuvering and accelerating. If the total gross weight is 200 lbs. it will hover at 55% power and will have enough reserve to still fly if you loose a motor.

Thanks for the input fellas. We are still in development of the craft, I will post some pics and video when appropriate with our timeline. However we did finally get props on her and spooled the motors today. Empty she wants to lift with almost no throttle input... its suprisingly quiet, T-Motor did a good job on motors and props.

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