Hi everyone.  Fairly new to the hobby and have been focused on larger aerial video multirotors, but have also done a couple cheap 250 builds.  But as the local drone racing scene has been rapidly growing, I thought I'd put together something raceworthy.  Here's a rundown:
Space One Formula 220X frame
Aikon 20 amp  ESCs flashed with BLHeli_S 16.4
Emax RS 2205 2300kv motors
SPRacing F3 Evo
Tattu 3S 75C 1300mah lipo

Now to the problem.  1st flight using DAL 5045 3-blade props, the quad lifts no problem and hovers solid, but the second I give it the least amount of throttle, it just drops out of the sky.  I doesn't disarm and the second it touches the ground, it's ready to take off again so I think I can eliminate any kind of signal issue

My first thought was just setup, but I've also tried F3 Mini, Naze32 and CC3D, all with exactly the same results so I think I can narrow it down to a power issue.

So I switched from the DAL 5045 3-blades to flimsy Genfam 5X3 two-blades and low and behold, problem solved nice and smooth even on full throttle punchouts.

I'd like to use at least 5040 3-blades, so I guess what I'm asking from the more experienced, is what in this setup is causing this. I know 4S is what 99% use and I've got some on the way, but even with these, ecalc shows that I won't be able to go above 5X3 props.  I guess what I'm trying to figure out what component is causing the issue as I'm assuming the redbottoms are just pulling too much current draw.  Yes I'm using 20amp ESCs but have 30amps coming.  Just hoping to get a little input like - hey, that setup should work, you need to check all your connections or on the flipside - your problem is ___ and you need to change____.  I'll post a pic of the wiring so you can see the setup, but it's pretty straight-forward.  Thanks

how are you powering your FC?

(10-Nov-2016, 06:14 PM)Oscar Wrote: how are you powering your FC?

Sorry, should have mentioned that.  Filtered 5V from PDB to motor #5 pins on the F3. And I've poked around on different pads on the board, always get 4.98V-5V

(10-Nov-2016, 06:37 PM)RENOV8R Wrote:    
Sorry, should have mentioned that.  Filtered 5V from PDB to motor #5 pins on the F3. And I've poked around on different pads on the board, always get 4.98V-5V

I just noticed the photo in the OP is extremely small

FYI, your 20A escs should be fine with 4s and 5045 tri blade. Remember that the current draw in the air is almost 30% less than static thrust tests.

(10-Nov-2016, 07:54 PM)oyvinla Wrote: FYI, your 20A escs should be fine with 4s and 5045 tri blade. Remember that the current draw in the air is almost 30% less than static thrust tests.

This is what I assumed, but if I test in ecalc it tells me I need to increase the amps.

Also, it's OK if I try 5X3 props.  As soon as I change to 4.5 pitch it wans that there's a risk of VRS and loss of control.

What receiver are you using? Could it be a short failsafe kicking in?

I suspect the pdb's 5V is not stable enough under load. Caps on pdb?

Did you try logging w/ SPRF3 or CC3D?

(10-Nov-2016, 08:45 PM)fftunes Wrote: What receiver are you using? Could it be a short failsafe kicking in?

I suspect the pdb's 5V is not stable enough under load. Caps on pdb?

Did you try logging w/ SPRF3 or CC3D?

Hmmm, never thought of that. I'm using a Radiolink AT9S and the R9DS receiver was too big so I switched to a much smaller R6DS.  I'm using this PDB.
https://www.spaceonefpv.com/collections/...1541108678

I don't know any of these components so really can't say wether there's any "usual suspects".

But looking at it from the other end: What flightcontroller firmware are you using, and did you adjust PID etc. when switching props?

I had something similar on a small quad where i had to lower PID significantly. Imagine a kind of superfast invisible oscillation which just burns a lot of power even when only hovering.

EDIT: Other reasons for too much power drain could be a short (conductive carbon) or bad solder joints.

(10-Nov-2016, 10:35 PM)fftunes Wrote: I don't know any of these components so really can't say wether there's any "usual suspects".

But looking at it from the other end: What flightcontroller firmware are you using, and did you adjust PID etc. when switching props?

I had something similar on a small quad where i had to lower PID significantly. Imagine a kind of superfast invisible oscillation which just burns a lot of power even when only hovering.

EDIT: Other reasons for too much power drain could be a short (conductive carbon) or bad solder joints.

I think I'll rule out a problem with faulty PDB as it did the same with the F3 Mini which has it's own internal 5V BEC.  Firmware is BF 3.0 with default settings.  I think I'll just put this aside until the new ESCs arrive, no use checking and resoldering everything and having to do it all over again when I change them.