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Building UAVFutures USD99 Racing Quad
#61
(21-May-2017, 01:39 PM)unseen Wrote: Looking good Mr. A!

I can't help wondering about the logical disconnect with these 4-in-1 ESCs though...

The RacerStar 4-in-1 you are using is described as being able to deliver 20A constant and 25A burst per motor. So in theory, it's capable of pulling 80A constant current, yet the power wires are 18AWG - which is rated for 22A, maybe 45A burst. Then we have the PDB which is rated for 25A constant, 30A burst per ESC connection.

So, even though the components should, in theory, be able to handle 80A constant current, only connecting the 4-in-1 to one set of ESC pads would exceed the rated load for those pads by nearly three times. The fact that this would also exceed the current rating of the 4-in-1's power wires by nearly four times tells me that this configuration would never be able to pull anything over about 40A as a constant load.

I've not seen a 4-in-1 ESC yet which has power wires that are even close to supporting what the device might actually draw. If there was such a thing, it would have power wires which are at least 14AWG, backed up by PCB traces to match.

How do you know that it's only 18AWG? I can't find specs on the wires anywhere... I know it's thinner than 14 gauge because I noticed that it was thinner than the 14 gauge LiPo wires (which I used to extend some of my motor wires, but used leftover wire from the power to the ESC for the others) but I never really measured them and my wire strippers are the kind that just pinch the insulation off. 

Scary stuff though since I am using very similar ESCs to Aaron... I will definitely be checking the temperature of these wires on my next flight just to be certain. 

Maybe it's done via magic? Mystical faeries and all that?
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
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#62
(21-May-2017, 01:52 PM)Carl.Vegas Wrote: How do you know that it's only 18AWG? I can't find specs on the wires anywhere... I know it's thinner than 14 gauge because I noticed that it was thinner than the 14 gauge LiPo wires (which I used to extend some of my motor wires, but used leftover wire from the power to the ESC for the others) but I never really measured them and my wire strippers are the kind that just pinch the insulation off. 

Scary stuff though since I am using very similar ESCs to Aaron... I will definitely be checking the temperature of these wires on my next flight just to be certain. 

Maybe it's done via magic? Mystical faeries and all that?

How do I know? Like this:

[Image: IMG_20170521_150307_zpsrqitv4nu.jpg]

Big Grin
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#63
oh, you got the same ones! now that makes sense... lol... I almost forgot that you said you were going to use all-in-one ESCs on the new build.
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
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  • unseen
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#64
Unseen raises very valid points about the current rating of wire and various components.

For my part I agree with every he points out, however I'll throw in a very carefully couched "but".

If we kick around online for a bit we can find a reference table of wire gauge (AWG or mm^2) to current to length. This exists because all wire has a level of resistance, it's very low but ohms law and physics doesn't change just because things are small scale.

So if we have a high current running over a long wire it warms up, run a lot more current and it will eventually melt away the insulation, then melt itself.

So we need to use wire that has low resistance (thicker or a lower AWG number) because for longer runs at a set current draw.

Where it gets funny is for extremely short runs (like in miniquad) the current tables would indicate a constant short interval draw of 30+ amps is ok on gauges below about 20AWG. Naturally you want to be sure the wire insulation has a good temperature rating.

I'll find a table and post it up here when I'm not using a phone Smile

I suspect wire gauge hasn't been an issue in the hobby because quite often a poor solder joint with heat up (same reason) and melt away breaking the circuit before the wire goes up in smoke.
Builds: Mini-Quad  -  Tricopter 
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  • unseen
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#65
Grabbed a couple of 4S 1300mah batteries from Hobbyking in a 24-hour sale. AUD38 for the pair delivered which is reasonable.

Only Zippy Compacts with a 40/50C rating. Will be enough for my level of skill to try 4S (and I can use in my Cheap250 as well).
Builds: Mini-Quad  -  Tricopter 
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#66
That's an amazing price! I don't think I've seen batteries that cheap in the US.
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
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#67
I think they're some of my more expensive batteries, I have been buying cheap deals from Hobbyking whenever they come up. It's just nice having the Hobbyking Australian warehouse less than a 4 hour drive from my house (next business day courier delivery for all of AUD6.42)....
Builds: Mini-Quad  -  Tricopter 
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#68
Yeah, now that I search again I see that batteries can be gotten much cheaper that I am paying for them... I already have 10 which is just about right for me for now but eventually I'll have to replace for damage or wear out so I might look into cheaper batteries.
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
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#69
Another week passes and I found a bit of time to spend on the 210mm build.  

ESC Wiring (Front)
The first thing I knew I had to do was remove the wiring for the motors from the ESC and extend the motor wires ever so slightly.  In the original Youtube video UAVFutures does a simple "chop and splice" at the mid-point of the arms then wraps them with tape.  I'm not Stew.

               

Yeah I'm the kind of guy that makes 12 wires tinned and ready, cuts 12 pieces of heat shrink exactly the same and then makes the sections of braid and dual wall symmetrical side to end etc etc.

         

The idea is to have the front motor wiring all inside the frame behind the FPV cam coming square onto the ESC.

         

The braid is run right up to and over the existing heat shrink on the motor.  The other end of the braid is exactly on the wiring join point, leaving me with  about 20mm of separate leads for joining to the ESC.

[Image: TRrMoXCl.jpg]

Pretty happy with the symmetry.  The red bands are small cable-ties through the mounting holes that normally would be used be the stand-off landing legs.  They raise the wiring slight, grab firmly and best of all aren't tape!

I'm very happy with the "look" on the front.  The rear will be different, same principles but the routing will be different.
Builds: Mini-Quad  -  Tricopter 
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  • kaitylynn, unseen, sloscotty, Carl.Vegas
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#70
Very clean indeed.  Thumbs Up
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
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#71
Love the loomed wires! That looks like a super clean build! Will be interested to see how you mount your camera.
SoCal Kaity :D
OMG, no one told me it would be this much fun!  Addicted :)
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#72
The receiver finally arrived this morning. Will be able to make a super clean build given that I can pick up the PPM and battery telemetry from the FC mounted directly below in the stack.

Looking forward to having have build time and getting more pics Smile
Builds: Mini-Quad  -  Tricopter 
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#73
Popcorn
The Obsession IS Real!
My Youtube and Instagram links
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#74
ESC Wiring (Rear)
As per the front motors I wanted the rear to have that neat industrial look with braid.  It's a little harder on these 210mm frames because the FC actually sits slight rearward, making the routing "interesting".  Sure if you are happy just taping things down it's not actually an issue, but if you are using braid and want a neat finish it's a little harder.  

[Image: sS2z34Ql.jpg]

Initially at least I have made the braided section a little longer than the front motor wiring and used a nice gentle curve around the rear to bring the ESC ends longitudinally into the ESC to complete the termination there.  There's not exactly many mounting options for them so instead I've set up to make the termination neat and once they are done I'll be able to revisit the layout. 

As the ESC is on the bottom of my flight stack and the XT60 is a layflat their current route will pass below the XT60 on the PDB.
Builds: Mini-Quad  -  Tricopter 
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#75
perfection on the price conscious build is not going to happen :p I love that you are trying anyway.

TBH the biggest thing that I should never have done based on this video but did anyway was the motor swap. There is no reason to swap 3+4 since the cables to the FC are swapped as well Doh... that would have made mine a little cleaner.. but no where near as clean as yours is...

Keep in mind... it's already beautiful... if you have a few little things sticking out we wont notice... The key thing is that it flies like a champ!
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
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  • RENOV8R
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