Wire Lengths???

[dethow]

Hey Guys,
I'm getting ready to start electrical work on my builds. I know wire length is best kept short. But my question... is it important to keep wires equal lengths?

Example of question. On my cat, the esc is mounted to one side and a have a 2S battery on each side. Can the wire coming off the battery on the same side as the esc be shorter then the one coming from the other side of the boat?

Also, same question from esc to motor. There wouldn't be major differences like the battery situation but I could make things look neater if wire were slightly different lengths.

Thanks in advance for any input.

[Make-a-Wake]

It will obviously work at different lengths but would be an "nth" of a degree less in overall efficiency I would imagine. Some folks need that extra efficiency when racing. I'm sure some of my wires are 1/4" off if I really measured them accurately.

[dethow]

Yeah... I can't imagine 1/4" would make much of a difference. But I'm talking about a couple inches difference with one battery having 3" wires to esc and the other being in the 6" area. I assume this will effect resistance but didn't know if its that's big of a deal.

[NativePaul]

I can't imagine it making any noticeable or even measurable difference either way but are the batteries in series or parallel?

If they are in series then even theoretically it doesn't matter if they are different lengths, shorter overall is better, even if 1 pack has a connectors soldered directly to the tabs and the other needs 8 inches of wire, any reduction to either packs wires is just reducing the total battery resistance.

If they are in parallel then theoretically the one with the shorter wire will have less resistance and have a higher voltage at the end of it's wires thus supplying more of the current and draining down lower than the other, in practice manufacturing variances will probably have more significance to start off with than a couple of inches of wire, and as one drains down lower, the one with the higher voltage will supply more current so they are self levelling to some extent.

[tlandauer]

What about ESC to motor? I thought they need to be the same length, could somebody chime in?

[NativePaul]

Motor wires should be the same length, and I do keep mine the same length, but then again with the wires coming from the pretty much the same place and going to the same place normally it should only take a few mm difference to make them lay neatly, and with electromagnetic waves travelling at over half the speed of light I cant see that affecting the timing too badly.

Those that have taken the newer Castle ESCs apart will have noticed that the wires are connected in a row laterally down the middle off the ESCs with the wires on a 200A version having about 2 inches between the longest and shortest, a way bigger difference than you would need to lay the wires neatly with most ESCs, I don't know whether the internal paths or circuitry of the ESCs compensate for that in some way.

[Fluid]

What about ESC to motor? I thought they need to be the same length, could somebody chime in?No, exact motor wire length is unimportant. Yes, the Castle ESC motor wires differ in length inside the wrapping. Using those Castles I've spun motors over 40,000 rpm in SAW racing, worked just great and set plenty of records doing it. So have many others. Bottom line - don't worry about a minor difference in motor wire length.



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[dethow]

Thanks for the input guys...
So... it sounds like it's always nice/best to keep as equal length as possible but not the end of the world or catastrophic failure if they're not.

[tlandauer]

Motor wires should be the same length, and I do keep mine the same length, but then again with the wires coming from the pretty much the same place and going to the same place normally it should only take a few mm difference to make them lay neatly, and with electromagnetic waves travelling at over half the speed of light I cant see that affecting the timing too badly.

Those that have taken the newer Castle ESCs apart will have noticed that the wires are connected in a row laterally down the middle off the ESCs with the wires on a 200A version having about 2 inches between the longest and shortest, a way bigger difference than you would need to lay the wires neatly with most ESCs, I don't know whether the internal paths or circuitry of the ESCs compensate for that in some way.
Thank you, sir!

[tlandauer]

No, exact motor wire length is unimportant. Yes, the Castle ESC motor wires differ in length inside the wrapping. Using those Castles I've spun motors over 40,000 rpm in SAW racing, worked just great and set plenty of records doing it. So have many others. Bottom line - don't worry about a minor difference in motor wire length.



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Thanks, Fluid, as always!