where to get big wires..

[dinie]

hi guys i jus bought a 17.2Ah yuasa batt.. tried installing it jus now but i used thin wires so the result was below par as the resistance of the wire's too high(resistance of wire is inversely proportional to diameter of wire).. so i need thick wires to support the current.. i dunno if household wires can be used as household currents run up to 13A only.. i need a place to get the wires ASAP before tuesday nite cos im goin to malacca on wednesday and i wanna try the batt out in full force alongside my spotlights and headlight.. Sim Lim's closed for half-a-week.. boo hoo.

[Strong Eagle]

I think you need to post the wattage of the devices you want to run. For example, at a nominal 12 volts, a 10 amp draw is 120 watts... quite a lot of lighting.

 

If you were to run a 55 watt headlight and two 55 watt spots your total would be 165 watts. This is a draw of 14 at 12 volts.

 

From this web page:

 

http://www.epanorama.net/documents/wiring/...resistance.html

 

You can see that for short lengths in open air, a 14 guage wire will work fine. Your other option is to run two wires.

 

Really, need more info to give a more specific answer.

[Limsteel]

Get HiFi Monster cable.

 

Actually I don't think cable poses much resistance diff. at high current the wire tend to get hot... So if the wire is too thin it will melt, or melt the insulation (will result short circult, if coat is melted).

 

Once during my DIY project, thin copper wire insulation melted when I attached 2 light bulbs to my signal.

 

LIke what SE stated, find out the power consumption and buy the wire with the correct rating or higher if you want some safety factor (remember to install a fuse)

[dinie]

Originally posted by Strong Eagle@February 19, 2007 08:54 am

I think you need to post the wattage of the devices you want to run. For example, at a nominal 12 volts, a 10 amp draw is 120 watts... quite a lot of lighting.

 

If you were to run a 55 watt headlight and two 55 watt spots your total would be 165 watts. This is a draw of 14 at 12 volts.

 

From this web page:

 

http://www.epanorama.net/documents/wiring/...resistance.html

 

You can see that for short lengths in open air, a 14 guage wire will work fine. Your other option is to run two wires.

 

Really, need more info to give a more specific answer.

yeap u got tt right strong eagle sir... 55w headlight, and 55w x 2 spotlights.. plus stebel magnum horns... so like wad u said its 165w.. which is 13.75A. but i need some allowances for the current surge upon starting of lights and future installation of HID headlights.. which is y i got the 17.2Ah batt.. so to be safe i need to get and 18A cable.. i only have thin speaker wires(red/black) but tt cannot be used as its too thin and it gets hot at the joints(where the thin wires meet the original batt wires. big batt is in my box as its really big so i made an extension with the thin wires).. therefore i need to noe where i can get thicker wires with at least an 18A rating by tmr nite..

 

Actually I don't think cable poses much resistance diff. at high current the wire tend to get hot... So if the wire is too thin it will melt, or melt the insulation (will result short circult, if coat is melted).

 

Once during my DIY project, thin copper wire insulation melted when I attached 2 light bulbs to my signal.

 

LIke what SE stated, find out the power consumption and buy the wire with the correct rating or higher if you want some safety factor (remember to install a fuse)

 

exactly bro.. tts why i need thicker wires or i risk melting the thin ones.. my bike's main fuse is 20A so i dun think its much of a problem..

[Strong Eagle]

Originally posted by dinie@February 19, 2007 01:22 am

hi guys i jus bought a 17.2Ah yuasa batt.. tried installing it jus now but i used thin wires so the result was below par as the resistance of the wire's too high(resistance of wire is inversely proportional to diameter of wire).. so i need thick wires to support the current.. i dunno if household wires can be used as household currents run up to 13A only.. i need a place to get the wires ASAP before tuesday nite cos im goin to malacca on wednesday and i wanna try the batt out in full force alongside my spotlights and headlight.. Sim Lim's closed for half-a-week.. boo hoo.

You have mentioned a couple of times that you have bought a 17.2 amp hour battery. I am trying to understand how this ties in with your lighting questions.

 

What the 17.2 means is that if you draw 1 amp from the battery it will maintain its voltage for 17.2 hours. If you draw 10 amps from the battery it will do so for 1.72 hours (actually it will be less depending upon battery construction). And if you draw 1/10 amp it will deliver the current for 172 hours before the voltage drops to about 11.5 volts.

 

So, it is kind of irrelevant to talk about the amp hours of the battery unless you plan to use only the battery to run the lights... for 165 watts of lights it would only keep them lit for about an hour.

 

Your charging system is more important. What is the rated output of your alternator? This is what matters. You can see from the diagram that my Valk alternator puts out 546 watts at 3500 RPM, and at 2000 RPM the output is about 36 amps or 504 watts (14 volts charging voltage of alternator).

 

All alternators exhibit similar curves so if you know the maximum output and the RPM you can pretty much figure how much current you will put out at various RPM's.

 

http://www.herbhost.com/miscimg/altout.jpg

[dinie]

tt is correct sir. according to my manual it says its generates 0.188kW=188W=15A. right now im using a 3Ah batt.. when i switch on both my spotlights and my headlight with the 3Ah batt, my lights go dim and the batt gets weak within 20mins.. so i can only use either the headlight or spotlights at one time. which sucks. thus i cld either get a bigger alternator which can provide me with spare 'on the fly' wattage or, i cld buy a bigger battery to give me 'stored' wattage which is cheaper i assume.

 

with everything on, the setup consumes almost 14A leaving me with only 3A(15A+3A-14A) for the spark plugs and charging of battery which is definitely not enuff.. therefore i need a higher surplus of current to offload some from the alternator. so with a 17.2Ah batt, i get 32.2A of current in one hour which leaves me a surplus of more than 18A which allows me to use the full lighting set up.

 

same goes if u wanna install a sound system for ur bike(which i seriously am not interested in). a 3Ah batt wont suffice. u need a bigger one.

 

ur right in a sense tt i'll use up the 17.2A in slightly more than an hour.. but then agn my bike is continually charging the batt and i wldnt be using the spotlights 24/7 so i guess it'll be fine.

 

to summarise,

 

current setup = 3A batt plus 15A alternator = batt goes flat within 20mins. no $$$ for a bigger alternator

 

intended setup = 17.2A batt plus 15A alternator = very good. but no thick wires to carry the big current to the original battery connector wires from my box. thus energy is wasted due to resistance in thin wires.

 

if u still dun get me, i wldnt mind meetin up to explain myself. it would be a pleasure to meet u..

 

anyways, tried goin Home-FIX to get 13A wires and run two of them each along each battery terminal according to ur suggestion the it's closed after 6pm. CNY for me is miserable man.. everything's closed. leaving for malacca soon.. so i guess i'll have to test the setup another time. darn.

[Strong Eagle]

OK... This makes much more sense and is the only way to go without a bigger alternator.

 

Just making some calculations on the back of an envelope:

 

Let's say that you don't always run at the max RPM that produces 15A, say 60 or 70 percent of it or so... then you get about 8 to 10 amps from the alternator... let's be conservative and make it 8 amps. (Actually, it is somewhat more complicated since you will generate 15 amps at higher RPM's and virtually nothing at idle while waiting for a light.

 

Let's also say that the entire electical system (your fancy lights, tail lights, ignition) draws 16 amps... could be a bit less. This means that you will need to draw 8 amps from the battery and that it will be fully discharged in about 2 hours of riding with lights on.

 

Then you will need to charge your battery. Let's say your turn off your two 55 watt spots. Your electrical load will drop by about 10 amps to 6 amps, giving you two amps (using 8 amp average alternator output) to charge the battery. At 2 amps it will take almost 8 hours to fully charge an 18 amp hour battery.

 

You might get a somewhat longer battery life if my estimate of alternator output is low or total current draw is high. You could play with the numbers some more.

 

For example, let's say that you get 12 amps on average, and use 16 amps for the load. Then, the battery will need to supply 4 amps and will last roughly 4 hours of riding. Turning of the spots (10 amps) now gives you a net charging amperage of 6 amps which will fully charge the battery in about 3 hours.

 

Either way I think you will also need a secondary charger to plug into the battery when the bike is parked because it will take too long to recharge the battery while riding with spots off.

 

Mustafa's and Carrefour are both open and both sell all kinds of electical wire including monster wire.

[gabriel06]

Originally posted by dinie@February 19, 2007 01:22 am

hi guys i jus bought a 17.2Ah yuasa batt.. tried installing it jus now but i used thin wires so the result was below par as the resistance of the wire's too high(resistance of wire is inversely proportional to diameter of wire).. so i need thick wires to support the current.. i dunno if household wires can be used as household currents run up to 13A only.. i need a place to get the wires ASAP before tuesday nite cos im goin to malacca on wednesday and i wanna try the batt out in full force alongside my spotlights and headlight.. Sim Lim's closed for half-a-week.. boo hoo.

hi bro.. be careful like u said ur wires are too thin.. do check ur bike manual.. your harness might not be able to take the load so take care bro..

 

u dont want to end up burning ur main electrical harness..

 

unless ur talking about wires for stand alone system of battery, relay, switch, your lights.. means u have to charge ur battery manually..