Re: Power Draw

["Marc en Wendy" <marcmethorst-at-zonnet.nl>]

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.
>