RE: Power Draw

["Bill Harris" <trollstomper-at-tds.net>]

http://science.howstuffworks.com/question260.htm

There's a link for wire gages...

Multi strand wire is more of a "braided wire" rather than having one solid
core running under the insulation.

> -----Original Message-----
> From: tanks-admin-at-rctankcombat.com [mailto:tanks-admin-at-rctankcombat.com]
> On Behalf Of Marc en Wendy
> Sent: Sunday, September 19, 2004 2:46 PM
> To: tanks-at-rctankcombat.com
> Subject: Re: Power Draw
> 
> For us Dutch, being on the metric side, can you tell about the gauge
> system?
> Our wiring standard is mm2, meaning the area of the crossection of the
> copper. Would there be a converting table for this?
> And I wonder what you mean by 'stranded wire'.
> 
> Marc 'habla poco Anglese Miester' Methorst
> 
> ----- Original Message -----
> From: "Frank Pittelli" <frank-at-rctankcombat.com>
> To: <tanks-at-rctankcombat.com>
> Sent: Sunday, September 19, 2004 4:21 AM
> Subject: Re: Power Draw
> 
> 
> > randall b reynolds wrote:
> > >
> > > HI everyone, I'm at the point in construction where I'm starting to
> > > think of wiring and a speed controller. I checked a book out of the
> > > library called "complete combat Robots". It has some formulas to
> figure
> > > out Wire size , Amount of amp. draw from a dead stop and running draw.
> > > Has anyone done this on their Elec. system, or have you used past
> > > experience, maybe ?  Any help would be appreciated.
> > >
> >
> > When it comes to wiring, you can't make the main power lines too heavy.
> >   Ev Warriors can pull over 70 amps -at- 12v when stalled, which is a very
> > large current draw.  During normal operations, however, the total
> > current draw is less than 30 amps, but that is still worthy of
> > heavy-duty wiring.  For that reason, I have doubled up my battery wires,
> > using two pairs of 10 gauge, stranded wire. (Stranded wire carries DC
> > current much better than solid wire.)  Alternatively, you can use 10
> > gauge wire that has twice as many strands as standard stranded wire.
> > They sell such wire for high-power audio systems, I think they call it
> > monster wire.  If I remember correctly, it has over 40 strands, whereas
> > standard wire has less than 20. I also run separate supply wires to each
> > side of my speed controller to reduce the current through each wire.
> >
> > With large current draws, you also need to consider how all the wires
> > are connected.  Conventional in-line power connectors, such as the ones
> > used on batteries, are usually not rated for such loads, so you have to
> > either double them up or connect the wire directly to a terminal strip.
> >     Direct connections are best from a power perspective, but whenever
> > you change batteries it is easy to hook them up backwards, which can
> > lead to some nasty surprises.  For that reason, I use polarized,
> > double-up connectors for all batteries and I use large spade terminals
> > and terminal strips for the rest of the wiring.
> >
> > You'll also need to get a cut-off switch that is capable of handling the
> > max current draw.  I use a 100 amp key switch that is normally used in
> > cars to disable the starter battery.  They are very durable and the key
> > is a nice bright orange so that you can easily spot it on the outside of
> > the tank.
> >
> > Finally, you'll want to include a high-amp, slow-blow fuse somewhere
> > between the batteries and everything else.  I use an 80 amp fuse that is
> > used for high-powered car stereos.  They come in different shapes and
> > mounting fixtures, but they all do a good job of safely shutting things
> > down if you short something.
> >
> > Frank P.
> >