Small 12v headlight relays?
Discussion
andyiley said:
Power = current x voltage, therefore
40 amp relay will therefore allow the relay to power a circuit using 480 watts assuming 100% efficiency.
I don't think you have headlights of over 400 watts!
Assuming you are switching 1 x standard halogen headlight you will only need to supply less than 6 amps, 2 will need less than 12 amps.
You can therefore use smaller relays with no issues at all.
Thanks. Yes, I do know the equation for power.40 amp relay will therefore allow the relay to power a circuit using 480 watts assuming 100% efficiency.
I don't think you have headlights of over 400 watts!
Assuming you are switching 1 x standard halogen headlight you will only need to supply less than 6 amps, 2 will need less than 12 amps.
You can therefore use smaller relays with no issues at all.
I have twin headlights:
2 x dual filament H4s. On flash, with all filaments (assuming 65W bulbs, although they will probably be 55W) it will be closer to 20A, albeit for short periods.
The automotive relays I do have are all labelled as 40A.
Mr2Mike said:
You'll need one relay for dip and another for main beam, so the current through each relay will only be half that.
Quite right! I know this, but stupidly thought and wrote it wrong. Oops. I'm trying to fit 2 relays in, which is the point of using smaller ones.
Lower current ones should do.
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