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        Discussion Let's talk power distribution

#1 iamsuperbleeder Aug 20, 2012 01:53 AM

Let's talk power distribution
 
For my quad's last setup I was just using 20a ESCs, so a HK power distribution board suited me well. Now I'm moving up to 30a ESCs, and the board isn't going to be up to handling the amp draw safely.

So I made a harness "squid" using 16 gauge and 10 gauge, but I don't think my main solder joints are very good; I don't think I got things hot enough to fully melt everything together using the method that I did (tieing the open tinned wire ends together with a single strand wire and then heating everything up and filling the solder in). The joint just looks like a big mess, lol. Feels strong, but I'm concerned about actually using it... Plus, I think the ends are just WAY too long, but that's easily fixed.

I'm going for a 10 gauge input wire splitting into four 16 gauge ESC wires, and I would like to use 2.5mm bullets on them to so ESC swaps will be easy it needed. I know using connectors add weight, but I think that little bit of weight should be negligible with this rig. I'm also trying to keep overall lengths down to keep from power fluctuations and killing ESCs.

I'm waiting on my motors to come in so I can mount them and the ESCs so I know just how long I need to make the wire leads, but in the mean time I'd like to see some home brewed ESC harnesses you guys have made and get some ideas. I've bounced around the RCG, Google, and YouTube and have gotten some ideas, but I'd like to see if there's another technique out there that would work good for my case.

Thanks! :popcorn:

#2 timecop Aug 20, 2012 02:04 AM

10 gauge? are you lifting a tank?
I think my quads are all 16 awg to battery.
but yes, your way of bundling wires together, tying with single strand and and then filling with solder works for me. Get a bigger soldering iron if you don't feel your current one melts good enough.

#3 iamsuperbleeder Aug 20, 2012 02:18 AM

Quote:

Originally Posted by timecop (Post 22495437)
10 gauge? are you lifting a tank?
I think my quads are all 16 awg to battery.
but yes, your way of bundling wires together, tying with single strand and and then filling with solder works for me. Get a bigger soldering iron if you don't feel your current one melts good enough.

lol, it might be 12, I'd have to look, 10 was a guess, but I know the ESC wire outputs are 16

#4 diakatche Aug 20, 2012 05:22 AM

2 Attachment(s)
Quote:

Originally Posted by iamsuperbleeder (Post 22495491)
lol, it might be 12, I'd have to look, 10 was a guess, but I know the ESC wire outputs are 16

I've run 16 and 12 with the ESCs all wired in series for my wethex design in the past. New builds wire them 3 in each chain instead of all six. Either way works flawlessly even though I had concerns of the higher current loads on the ESC power wires closest to the battery. Turns out there was no need to be concerned.

As for power distribution, I've use off the shelf and custom boards, bus strips, hard wiring, deans connectors soldered together, 3 x 4 way crimp connectors, and power posts. All works just depends on what your frame is made of (power posts require a wood of fiberglass mounting. Any metal or carbon is bad). and how much room you have to route power wires.

#5 vineet_p Aug 20, 2012 06:47 AM

I plan to use 18AWG between LiPo and ESC, draw will be around 20A per motor. Is it o.k?

#6 TS00 Aug 20, 2012 06:51 AM

Quote:

Originally Posted by vineet_p (Post 22496443)
I plan to use 18AWG between LiPo and ESC, draw will be around 20A per motor. Is it o.k?

You don't really draw 20A per motor. If you did, your 80A machine would fly for 1.5mins on a 2200mAh pack.

Your average draw per motor will me more like 4A. So your 18AWG battery wire will be absolutely fine (as long as it's soldered well).

OP - your method is spot on, but like TC says you need a bigger soldering iron. To do really big 4 > 1 bundles, you need a 50W iron with a big tip.

#7 vineet_p Aug 20, 2012 08:24 AM

Quote:

Originally Posted by TS00 (Post 22496461)
You don't really draw 20A per motor. If you did, your 80A machine would fly for 1.5mins on a 2200mAh pack.

Your average draw per motor will me more like 4A. So your 18AWG battery wire will be absolutely fine (as long as it's soldered well).

OP - your method is spot on, but like TC says you need a bigger soldering iron. To do really big 4 > 1 bundles, you need a 50W iron with a big tip.

Thanks TS00. Can i draw three 18awg wires thru a 10*10mm al square tube?

#8 TS00 Aug 20, 2012 09:44 AM

Quote:

Originally Posted by vineet_p (Post 22496969)
Thanks TS00. Can i draw three 18awg wires thru a 10*10mm al square tube?

There is enough space, but it will be very fiddly work. Lubricate with a bit of WD40 or silicone oil when pulling them through, and make sure they aren't rubbing on sharp edges.

#9 vineet_p Aug 20, 2012 10:12 AM

Thanks... :)

#10 iamsuperbleeder Aug 20, 2012 10:13 AM

Quote:

Originally Posted by TS00 (Post 22496461)
You don't really draw 20A per motor. If you did, your 80A machine would fly for 1.5mins on a 2200mAh pack.

Your average draw per motor will me more like 4A. So your 18AWG battery wire will be absolutely fine (as long as it's soldered well).

OP - your method is spot on, but like TC says you need a bigger soldering iron. To do really big 4 > 1 bundles, you need a 50W iron with a big tip.

I'm actually using a 60watt iron and a chisel tip, but it's a cheaper RadioShack adjustable one so its probably not really 60watts, lol. I really need to just put money down on a good Weller...

#11 Sad Sack Aug 20, 2012 04:25 PM

18awg wire is pretty much the quintessential standard for hobby grade multirotors.

Very suitable for LiPo to ESC cabling. ESC to motor can use even 20awg or so..


1. Silicon insulated 18awg cable.
2. Flux.
3. A powerful iron.
4. Profit???

#12 dutchcommando Aug 20, 2012 09:13 PM

don't know if it helps..
but here's my power distribution and harness:
http://i1106.photobucket.com/albums/...a/DSCF6618.jpg
http://i1106.photobucket.com/albums/...a/DSCF6615.jpg
(yups is heavier than some quads!)
10 AWG from lipo to power board, 10 AWG from powerboard to first split, 14AWG from split to esc, 12 AWG from first split to second split.

it's for a H shaped hexa that will become a very heavy lifter in the future. (now "just" 3KGs uaw) at the moment it has 6X 30A esc's, but that will become at least 60Amps per esc in the future. (the aim is to make a very fast and responsive H-hexa with auw of around 8-10KGs.
(money makes it "in the future" big esc's and big motors do cost plenty;) )

the power distriboard is "modded" and the tracks are 5MM wide and 3 mm thick..
it now has 2 lipo connectors and 2 strands of wire harness (ow and 4 small connectors for misc usage such as 5V bec feed for FC, 12V out bec feed for downlink and such shenanigans..


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