why diesel van goes slightly slower with headlights on?

2017-07-17T14:11:27Z

why does my van go ever so slightly slower when i swithc them on?i notice this when im just rolling along in 2nd hardly any throttle.

M.2017-07-21T06:53:29Z

Favorite Answer

746 watts per 1 horsepower.

Headlights, taillights, other lights?
How many watts total?
75? That's 1/10 horsepower.
150? That's 1/5 horsepower.

boy boy2017-07-17T15:14:03Z

your imagining it ..and so are you guys who say its the alternator ...the loading on an alternator does not change ...its output might ..but not its loading ...stop staring at the light!!

Philomel2017-07-17T15:10:53Z

With the headlights on the generator is loaded up and the idle is slower so the car moves slower.

?2017-07-17T15:05:49Z

The alternator has to work a bit harder to power up those headlights, and since the alternator is belt driven by the engine, when it works harder, the engine also has to work a bit harder, hence the slight engine power drop.

Anonymous2017-07-17T14:16:08Z

idk