Daytime Lights

[NimbleYarisOwner]

OK so 55W*2=110 watts
with ~30% engine efficiency thats 366 watts or approx. 1/2 hp.
from there you can figure out your gas quantity to make that power.

[BailOut]

Originally Posted by NimbleYarisOwner

OK so 55W*2=110 watts
with ~30% engine efficiency thats 366 watts or approx. 1/2 hp.
from there you can figure out your gas quantity to make that power.

The engine's efficiency doesn't apply here as the alternator is capable of producing 20A while in its "idle" state. The only way you could make the alternator drag less would be to remove it from the vehicle. The 30% rule would only come in if you are drawing more than that 20A.

20A * 12V = 240W, so you have 240W to play with before the alternator clutches and really starts creating drag.

[bearda]

So it's 1/2 hp in the worst case, when the rest of the devices on the vehicle are collectively pulling 20A or more and the alternator is going to drag down an additional amount based on the DRL draw, right?

So you're looking at about around a .5 % increase in efficiency if you;'re constantly dragging down the alternator. Keep the DRL, the extra visibility is worth it.