Question for all you bright sparks

[Steffan]

I have fitted a new alternator to the Black beast (bullet 500). It is a 120Watt item; now I want to change the two wires between this and the Reg/Rec but being the cautious person I am I wanted to double check my logic as the wire I bought looks awfully light.

120W/12V = 10Amp
Therefore I have bought 16.5Amp wire (allowing a margin)

So all you bright spark and engineering types, have I got it right or wrong?

Steffan

[guest40]

As a boy from Oz you should know that anything less than fencing wire is a waste of time and money, a bit of old inner tube or garden hose would suffice as insulation too. Besides the rest of the fencing wire can be used as the conventional Ozzie spare parts kit.

[Steffan]

Mate, I once towed a boat across Queensland from Morven to Camooweal with the tow bar lashed to the car with wire, later we used cable and a D bolt but intially it was fencing wire. Actually it was an old XB Falcon stationwagon (Estate) and the tow bar in these cars was connected to the bumper (back when cars had bumpers) but the bumper fixings had rusted through so the drivers side had given way and dragged on the ground. Thus we lashed the bumper back to the car with the wire and then put the boat back on the hitch. Took three days to drive it and you never forgot it was there. Cos you kept expecting to see it disappearing in the rear vision mirror

Steffan

PS not a big help mind mate.

[guest40]

 55 watt (headlamp)+plus 21watt (Brake )+ 7 watt (Tail) +10 watt (3 small globes instruments) +42 watt (2xindicators) + horn ? watts + running amps,   thats over 120watt, at night while braking towards a turn and warning that pedestrian, but your battery will act as an accumulator for the temporary loads.     
You would probably only be pulling 80 watts at night. Thats about 7 amps.                                                                 
 16 amp should be adequate to run to the battery to keep it charged.
Thicker wire does work better as there is less resistance. I sometimes use the 240 volt copper stuff for my main leads as not so much energy is lost in resistance and heat . 
Manufacturers use the thinnest (bad) shortest wire (good) they can to keep costs down.

[guest146]

And it wont be charging to its full amount for much of its time.Should be fine.

Ken