lighting relay question

[newmexTR3]

Hey guys,

This is probably a stupid question, but I don't know the answer. I have two driving lights with 55w bulbs that I want to install. I bought a relay rated at 40A/12VDC.

Will this relay work with those lights? I'm not sure how much current they draw.

Thanks,
Gavin

 

[Twosheds]

Ohm's Law for power. I=P/E

P=55W x 2 = 110W

I=?

E = 14V I use 14V instead of 12V because that's what the generator puts out.

110W/14V = about 8 Amps.

Well within the relay rating.

 

[TR6oldtimer]

On the relay, just make sure it is a constant duty relay thus capable of staying energized all the time. If it is an intermittent relay, like a horn relay, there is a possibility the relay coils could overheat, and poof, gone.