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Re: Gauging wire

Posted: Tue Apr 19, 2011 3:37 am
by Neosophist
I should have put you need to work out the likely load before deciding on the cable :ugeek:

If you look at the battery specs youll find either CA or CCA (Cranking amps)

This is the maximum amount of juice the battery will throw to the starter motor for at least 30 seconds.

Your never ever likely to exceed this from the battery, even when starting with thickened oil on a cold day as these bikes dont really take a lot to kick over.

Lets look at the NC24.

This bike has a bigger batter than the NC30 as stock and will supply 80A Cold crank current (EN)

Manufactureres use the smallest possible wire gauge as copper is expensive.

You only have to look at the size of the wire from the Battery +ve to the starter motor solenoid to see how thin it is, granted it is a really short run. Cant you recycle some old starter motor cables? They carry the full battery load and are of a good length?

Looking at this chart 4 gauge would be idea as it is chunkey.

http://memcarnew.dev.archermalmo.com/su ... age-chart/


However, I would personally use some 8 gauge like this

http://cgi.ebay.co.uk/8-Gauge-AWG-10mm- ... 25606ac61f

10.00gbp for 5 meters, should be more than you need and isnt too chunky.

Its quite cheap and since your only likely to hit peak output when starting which isnt too long the continious power of the cable will be less.

Re: Gauging wire

Posted: Wed May 04, 2011 11:52 am
by Drunkn Munky
Sorry to drag this back up but just getting round to ordering the cable. That 8 gauge cable, 10mm2. Does that mean its 10mm thick? The cable will weigh more than the battery if i use that stuff :grin:

Re: Gauging wire

Posted: Wed May 04, 2011 11:57 am
by porndoguk
Drunkn Munky wrote:Sorry to drag this back up but just getting round to ordering the cable. That 8 gauge cable, 10mm2. Does that mean its 10mm thick? The cable will weigh more than the battery if i use that stuff :grin:
no 10mm2 which will equate to about 8mm diameter,

Re: Gauging wire

Posted: Wed May 04, 2011 12:05 pm
by Drunkn Munky
Ok 8mm square i can live with that but the connector i need to put the wire in only measures 7mm tops
DSC03857.JPG
God i sound like a right numpty dont i :grin:

Re: Gauging wire

Posted: Wed May 04, 2011 1:47 pm
by porndoguk
before you order ill go measure some 10mm2 6491X the type of cable youll find on your gas and water tap (domestic - main earth bonding)

Re: Gauging wire

Posted: Wed May 04, 2011 8:48 pm
by mruehl34
If i understand the question you need a 2,5mm² cable.

Michael

Re: Gauging wire

Posted: Wed May 04, 2011 10:59 pm
by porndoguk
porndoguk wrote:before you order ill go measure some 10mm2 6491X the type of cable youll find on your gas and water tap (domestic - main earth bonding)
right, 10mm2 cable measures 6mm dia.

you only need a cable for 40amp rating the fuse is rated at 30amp so its never going to pull more than 30amps without the fuse blowing,

the cables you sent me links too are OVERKILL

extra weighty too!

i dont think 2.5mm2 will be up to the job Micheal, in 230V 2.5mm is rated for 20amps ish, (depending on the method of installation) but thats at Higher voltage than 12V so in ohm law, means lower current

the science bit

higher voltage = lower current
lower voltage = higher current

id be inclined to say 6mm2 for 12V bike, 6mm2 equivillant in AWG
tony go to a chavvy car shop that sells the biggest badest stereos! and buy some 40amp amplifier cable, it will measure about 4mm dia, or get a amp wiring kit for a car

http://cgi.ebay.co.uk/250W-CAR-AMP-AMPL ... 3a60645c98

Re: Gauging wire

Posted: Thu May 05, 2011 12:03 am
by porndoguk
found this too
http://www.vaplastics.com/elec/referenc ... ctors.html

looks like whilst doing my research 10 AWG is the cable youll need (6mm2)

http://cgi.ebay.co.uk/POWER-CABLE-10AWG ... 587f8749af

Re: Gauging wire

Posted: Fri May 06, 2011 11:17 pm
by spanky
You just need cable rated higher than your fuse... If your fuse is 30A then you just need a cable rated higher, that way the fuse will blow before you get a chance to overload the cable. It doesn't matter what the battery can supply, or what the starter motor is rated at because the fuse is your limiting factor. Also, if you're running a couple of feet of high amperage cable from the front of the bike to the back then consider fusing it close to the battery to protect against mishaps...

Out of interest how much was the fancy-dan battery and what's the Ah rating?

Re: Gauging wire

Posted: Sat May 07, 2011 12:31 am
by Drunkn Munky
That makes sense to me, im considering moving the starter relay up front aswell to save on cable run and keep it all together.

It was about £140 i think with all the connectors, heres a link http://shop.durbahn.de/shop/en/products ... er-Durbahn
Mines a A123 LiFePower Pack 2.3 Ah