Spot Lamp Electrical Loads

[NylonAdmiral]

I'm thinking of getting some spotlights for the truck and wanted to check what the load load limitations are.

I'm sure I remember someone who knows about this sort of thing telling me about some simple calculation to determine the number of lamps, and what wattage, it is safe to run.

Unfortunately this isn't really my strong point so wondered if anyone thinks this sounds familiar?

Thanks

[Jordi]

I could do with that info too.

[Hodgie812]

Not sure on all proper electrical bumff, but you can use led or smd bulbs in the lamps. They draw hardly any power/current and are bright as hell.

Just be careful on which bulbs you buy as I've had experiences of them not fitting through the hole in the reflector.

[kiwizook]

the size of the lights you can run depend on the size of the cable you run, and the free load available on your alternator, ie, your total power draw must be within the capabilities of your alternator, or else you will drain your battery. at 12 volts, every 12watts will draw a single amp, so this can be used to calculate the current draw of a set of lights.

Hope this helps a little

[NylonAdmiral]

Thanks Kiwizook,

So if I assume that my head lights are both running 55W bulbs then that's drawing about 9.2 amps?

I have no idea what a running engine draws but some people online are speculating at somewhere around 40amps?

So basically if I assumed my engine running with the headlights on was something like 50amps, then I just need to know what output the alternator is. If it's something like 55 amps (which I've seen a few Vitara alternators rated at) then that would leave me with 5w "spare" which would only give me about 60w to play with?

Am I heading in the right direction here or have I got it completely wrong

Hodgie, thanks I'm looking at LED options too. Just need to make sure I know what I'm doing first

[turbo-tom]

I have standard vit alternator. 5x55watt driving lights 2 extra side lights a pair of extra flashers and some led flashlight lights and it all seamsto cope fine.

[NylonAdmiral]

LOL, thanks Tom, well that kind of makes my approximations well wrong then!

Well I'm reckoning that 1-4 extra 55w lamps should be OK then...

[turbo-tom]

Lol just remember to use fuses and relays.

[NylonAdmiral]

Thanks Tom, will do. I'm not too bad at doing the actual wiring etc, I'm just definitely bad at working it all out!

[Darrell]

Kiwizook is correct

Watts divided by voltage = Amps