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#21
29-02-2012
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WOW!!! I AM TOTALLY BRAIN DEAD!!!
after that post i am totally shocked... i think we got our expert!!! and being honest i never considered the voltage drop when looking at wires!!! and serious a drop in 1V... wow... and yea ill be honest... coming from NORTHERN ireland (sorry i just always like doing that) we tend to use the phrase 'that'll do rightly' basicly in proper english it translates to 'that will do...' (at least thats the way i roll !!!  )
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#22
01-03-2012
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I was actually expecting someone to crunch the numbers for the electrics in their car. CHILL guys!
Hey, I was going a little over the top with the numbers to make the point that it does matter which wires you use, just not for us mortals. For those wanting to know some real numbers, let's say: Copper wires: a=0.017 Length 20cm=0.2m Diameter=3mm Temperature=20°C R=(0.017*0.2*4)/(pi*3²)=0.0005Ohm Thus the voltage drop is actually 100A*0.0005Ohm=0.05V per wire. For a 4000kV motor that's 4000*0.05*3= 600rpm But still, for the top drivers, that is important. For us mortals and me as an amateur, I don't care. So if you shorten the wires to half the size, the loss is cut in half also. And don't forget, you probably loose most by using connectors. All that said, I never cut the wires and use connectors, just because I like to switch and this way is the easiest (be it messiest) way for me. But then again, it wouldn't matter anyway because my driving is, to say the least hilarious. 
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#23
01-03-2012
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Quote:
__________________
Team C TC02c - My son breaks it, I fix it.
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#25
01-03-2012
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Whilst your maths is correct, you do assume that 100A is being drawn continuously which is not the case. You'll get this draw in very small pulses but if you were really drawing 100A all the time most speed controller fet pcbs would have melted way before 100A was flowing.
Bottom line is any voltage drop seen would occur for a small period of time.
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#26
01-03-2012
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#27
01-03-2012
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I totally agree imull, but every time you gun the throtlle, you're drawing the amps, so in all you got more power to use coming out of the corner.
And as most corners have a few of those ... But as stated before 99.999% of us won't notice the difference.
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#28
01-03-2012
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Quote:
__________________
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#29
01-03-2012
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Quote:
bazinga
__________________
Mattys the driver,my names carl
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#31
01-03-2012
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I've got a degree in electronics and design stuff for a living and I had to go back to the text books to find references to the equations sleenad called up, as it's much more in the electrical domain. They really are separate subjects!
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#32
01-03-2012
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This is a funny hobby! Short wires, low resistance gold connectors and 90c batteries for absolute maximum power then choose a 6.5 turn motor because a 5.5 turn is too powerful. Spend a fortune on lightweight carbon fiber parts and then add a load of lead weight to weight it back down. Ceramic bearings to reduce resistance and then add a bit of drag brake on the Esc for some rolling resistance on track.
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#33
01-03-2012
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with how much power is available to us now and the capacity of modern batteries etc, it all really doesnt matter that much anymore, back in the eighties running 1200sc's and 1400 scr's, every millimetre of wire and every ounce of weight mattered if you wanted to get to the end of the race without dumping. oh it is so nice not to have to clean your brushes between races anymore, i bet you dont see many people charging thier 7.2's by dumping them across a 12V car battery any more either!!
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#34
02-03-2012
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and again am only partly through my degree... so looks like i still have a lot to learn...
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#35
02-03-2012
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And the more power you can deliver, the more heat you get. And as for weight, that's all about choice. Many racing cars (1:1) can be made to drop in well below their classes lower weight limit. So they play with weight distribution/ballast (where its allowed) to improve handling. So its not just this hobby, its anything that goes forwards under power. They even spend millions making sure your 1.0L econobox commuter car has minimal losses/optimum heat rejection and good weight distribution. (well, in most cases.......)
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#36
02-03-2012
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This is A Level physics stuff. For homework I would like you all to read through this page and attempt the problems at the bottom
http://en.wikibooks.org/wiki/A-level...d_Conductivity (Teaching physics is what I do!)
__________________
Team C TC02c - My son breaks it, I fix it.
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#38
06-03-2012
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I guess that comes down to if you've taken your eye off the car for a second. In that second your car could exist in both states..........
Normally the sound of crunching carbon fibre tells me which state my car is in though.
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#39
06-03-2012
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Quote:
 Wise words
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