# [EVDL] chassis ground wiring



## EVDL List (Jul 27, 2007)

Considering the quanity of digital switching noise in the motor controller
and the DC/DC as well, the best alterntive is to run both (+) and (-) leads
to the battery which will act as a great filter device ad run two wires to
each acessory using 12 volts, also twist the two wires (+) and (-) together
a minimum of 3 twists per foot which minimises both absorbtion of noise from
other wiring and minimises inducing as much noise to other wiring as well.
But don't take my word for it I have only been licensed by the FCC since
1976. In a "normal" ICE Vehicle the noise generated is from the ignition
wiring. and a liittle from the alternator. Note do not add capacitors
indescriminately or a "Resonant circuit" may be formed and create
circulating currents sometimes more than 100 times normal current levels.
Just twisting the wires together (With good insulation) is effective and
simple to implement. Using the chassis or body for the negative conductor is
penny pinching it is better to only connect (-) to frame at the battery only
and no where else. Also, brake lights and turn signals if tungsten fillament
bulbs, are noise immune, but be careful with power feeds to electronic solid
state systems, digital circuitry will ignore noise up to a certain level but
above that it goes nuts!
Regards,
*Dennis Lee Miles* (Director) *E.V.T.I. inc*.
*www.E-V-T-I-Inc.COM <http://www.e-v-t-i-inc.com/> *(Adviser)*
EVTI-EVAEducation Chapter
*
++++++++++++++++++++++++++++++++
The "Stone Age" didn't end because they ran out of Stones;
It ended because they started using their Brains !
+++++++++++++++++++++++++++++++++++++++++++++


> Brian Pikkula <[email protected]> wrote:
> 
> > Two quick questions.
> >
> ...


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## EVDL List (Jul 27, 2007)

Hi Dennis,

Is there any advantage to using screened cable a/ at all, b/ between 
DC-DC and 12v accessory battery or c/ between charger and traction 
pack as well as twisted pairs? If so, the only readily available (ie 
cheap), screened, medium to heavy gauge cable I can think of is SWA - 
would the 'screen' work effectively enough to warrant its use?

Regards, Martin Winlow
Herts, UK
http://www.evalbum.com/2092
www.winlow.co.uk




> Dennis Miles wrote:
> 
> > Considering the quanity of digital switching noise in the motor
> > controller
> ...


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## EVDL List (Jul 27, 2007)

Martin, (and others)
The use of screened (That is "Shielded" in the States) cable is not a
necessity at the frequencies involved. The "Faraday Shielding" of the screen
only blocks capacitive coupling, while the twisted wires provide a
cancellation of both capacitive and inductive coupling between other
conductors and the twisted pair of wires. Also the pricing of two high
amp-capacity wires is much lower than the price of screened wire with
suitable conductors for several dozen amperes of current carrying capacity.
(Even a heater fan motor draws over 10 amperes of current at 12 volts.)
More important than the charger wiring which is only at a fairly
mediocre current is the battery pack to motor controller and controller to
motor wiring; these should definitely be twisted pairs of (+) and (-) well
insulated and with proper sizing of the copper then twisted as neatly along
the length as possible at three to five twists per foot (10 to 15 twists
per meter) {Snicker LOL, I know you understand "Colonial English" but many
of my Countrymen do not comprehend the "King's English..."}
Regards,
*Dennis Lee Miles* (Director) *E.V.T.I. inc*.
*www.E-V-T-I-Inc.COM <http://www.e-v-t-i-inc.com/> *(Adviser)*
EVTI-EVAEducation Chapter
*
++++++++++++++++++++++++++++++++
The "Stone Age" didn't end because they ran out of Stones;
It ended because they started using their Brains !
+++++++++++++++++++++++++++++++++++++++++++++


> Martin WINLOW <[email protected]>wrote:
> 
> > Hi Dennis,
> >
> ...


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## EVDL List (Jul 27, 2007)

> Martin WINLOW wrote:
> > Is there any advantage to using screened cable a/ at all, b/ between
> > DC-DC and 12v accessory battery or c/ between charger and traction
> > pack as well as twisted pairs?
> ...


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## EVDL List (Jul 27, 2007)

> Dennis Miles wrote:
> > the pricing of two high
> > amp-capacity wires is much lower than the price of screened wire with
> > suitable conductors for several dozen amperes of current carrying capacity.
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> > Martin WINLOW wrote:
> >> Is there any advantage to using screened cable a/ at all, b/ between
> ...


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