Hello,
I was wondering how to reduce the wire thickness in auto headlight system.
I am using 2 of 100W bulbs, 12V battery and 2.5mm² wire of 2 meters.
I want to use 1.5mm² wire instead of 2.5mm²... I saw in many cars 1.5mm² wire is used but i cannot figure it out how they do it to control wire heating and damaging...
It would be great if anyone can help me in that...
Thank You!
Hi,
I am not exactly sure what you are doing there so i'll just provide some general information.
If you are running two bulbs with wire that has cross sectional area A, then you can run one bulb with a wire that has cross sectional area A/2. This means if you drive each bulb individually you can use a smaller wire.
Shorter runs of wire can use smaller wire. Number 14 gauge wire is a standard for 15 amps, but over shorter runs you might get away with 16 gauge, and you might be able to squeeze 17 amps out of it for a short run. What you should do is test it and see if it gets hot.
You also need to check for voltage drop. If the voltage drop is too high you'll loose power getting to the bulb(s) and that makes them quite a bit dimmer.
There's no way to make a wire that is already getting hot get cooler without some means of cooling such as fans.
Also, the wire insulation has something to do with it too. If the wire insulation of one wire is rated at a higher temperature than another wire, that wire will be able to pass more current before it starts to melt the insulation.
If you really need to use smaller wire then perhaps you can run each bulb separately, or even just parallel two sections of the thinner wire and drive them both. Two wires that each have area A make a wire that has area 2*A which can handle about twice the current.