Electrickery

slim jim · Mar 17, 2009

I spent today wiring up for two work lamps that Im waiting for(ebay) This is the first time Iv tried my hand at wiring apart from changing a fuse or bulb and with out landyzone advice I would not have tried to. Anyway Iv wired both the dash switch and the lamps direct to the battery and Iv 4 earths all to the chassy one for each lamp, the switch and the relay. Iv used 8 amp wire from the relay to the lamps (they are each 55 watt) and the same wire for the earths. The only fuse is a 20 amp between the battery and relay. I got two 100 watt spot lights fited three week ago so I think a voltmeter might be the next mod. Iv read on another foram that wiring a voltmeter direct to the battery will drain it in no time. So will my work lamps or switch not do the same thing or when the switch is off is everything off. Oh yeah the realy and wire to the battery came as a kit with the fuse and fuse holder already made up. Well do ye think it will work or I have I made an obvious mistake I wont know for sure until I get the lamps

dannyboy 270781 · Mar 17, 2009

If the switch is open then no power can reach the consumer.

It's a good idea to remember that the switch does not carry load, if it did it would soon burn out. It mearly switches the relay. The relay supplys the current demanded by the consumer (in this case the spot lamps) from the battery. If the switch is open the relay is open hence no circuit and no consumption.

If you are planning to install a volt meter i think you would be best installing a switch in the circuit. I believe you can buy them with switches built in so when pressed the battery voltage is displayed.

Once you have finished you installation you can check the current consumption with everything turned off by connecting an ameter between the negative lead and the negative pole of the battery. The reading doesn't want anything higher than 0.4 amps, although the effects of this reading depends on the AH (amp hour) rating of you battery.

For example: if you a 74AH battery and you have a current consumption of 1 amp then it will take 74 hours to completely discharge the battery. Having said that the point at which it will no longer start the vehicle may be far less.

Best of luck!!

slim jim · Mar 17, 2009

Cheers dannyboy Iv more confidence in it now

boydy1989 · Mar 18, 2009

only thing... you've used 8 amp wire with a 20 amp fuse... this means the wire will melt before the fuse blows, not what you want! You need to use much thicker wire, especially with that much current going through it you will experience a voltage drop along the length of the wire, so reducing the efficiency of the system.

Hope this makes sense!
Boydy

slim jim · Mar 18, 2009

This makes sense. The wire between the battery and relay (where the fuse is )came as a kit so this wire should be ok. When looking for wire 5 amp was rated to a max of 60 watt so just to be safe because it has a long way to travel I got 8 amp and that was the biggest they had. It took ages to fish it all through a conduit, what wire should I get then? A smaller fuse is out of the question I soppose

The Mad Hat Man · Mar 18, 2009

You are using thin wall automotive wire, arent you?

boydy1989 · Mar 18, 2009

if you'e run two wires, one from each lamp to the relay thatll b OK, but put a 10 amp fuse in it.

you should only have 3 eaarths though, one for each lamp, and one from the coil of the relay.

WHere is your fourth? Even with a 3 position switch this isn't required.

slim jim · Mar 18, 2009

Yes its the right wire. Ill change the fuse then and the third pin on the switch has ground printed on it so thats why I earthed it. Thanks for all your help

Sean · Mar 18, 2009

slim jim said:
Yes its the right wire. Ill change the fuse then and the third pin on the switch has ground printed on it so thats why I earthed it. Thanks for all your help

is it an illuminated switch ?

The Mad Hat Man · Mar 18, 2009

:nopics:

slim jim · Mar 18, 2009

Sean said:
is it an illuminated switch ?

Yes in case I forget to switch it off. Its the red one in the pic

The Mad Hat Man · Mar 18, 2009

in that case - it may well need an earth for the warning light.

slim jim · Mar 19, 2009

Got the lamps today but with no instructions and I cannot make them work. The switch in the cab lights up ok and Iv rang wipac, they told my that they are doing a stock and would call back. Anyway heres a pic any sparky out there able to tell me what connects to the bulb,earth and live?

Pikey · Mar 19, 2009

well they'll only have 2 connections an earth and a live? so if they don't work.

Check for voltage on the live supply wire? if you've got 12v then it goes to the wire supplying the bulb & you need an earth to the other connector.

slim jim · Mar 19, 2009

So the wire goes to the bulb then, there is also a wire coming from the bulb with spade connector on it

Pikey · Mar 19, 2009

boydy1989 said:
if you'e run two wires, one from each lamp to the relay thatll b OK, but put a 10 amp fuse in it.

you should only have 3 eaarths though, one for each lamp, and one from the coil of the relay.

WHere is your fourth? Even with a 3 position switch this isn't required.

4x55W = 18.5 amp so a 20amp fuse is the correct one to fit. and it should sit between the battery & the relay. If he then runs each lamp on a seperate feed after the relay it won't cause any problems. My self personally I prefer to run a 4mm wire to the last lamp in the circuit and for the other 3 lamps I cut away the insulation and Solder a side branch to each lamp onto the main feed wire.

so you end up with something that looks like this

I--Lamp 4
I
I----Lamp3
I
I----Lamp2
I
I----lamp1
I
I
I____Relay____20amp Fuse____Battery

Pikey · Mar 19, 2009

slim jim said:
So the wire goes to the bulb then, there is also a wire coming from the bulb with spade connector on it

NO the live goes to the wire coming from the Bulb. If theres a spare wire coming form the bulb This is designed to allow you to loop onto the next lamp.

slim jim · Mar 19, 2009

Im on the way out to buy a volt meter then Ill try again

The Mad Hat Man · Mar 19, 2009

yu obviously dont knoe wot yu are doing - so just take it to an auto electrician. Its cheaper than telling the insurance company its on fire.

slim jim · Mar 19, 2009

The Mad Hat Man said:
yu obviously dont knoe wot yu are doing - so just take it to an auto electrician. Its cheaper than telling the insurance company its on fire.

Cant argue with that. Its called the school of hard knocks

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