I will admit, I don't even change my own oil! Not really "mechanically inclined" (just ask Jesse and Randy, my motorcycle guys!). So when a co-worker told me it's always a good idea in this cold weather to turn your headlights on for about 15 seconds before starting it to give your battery a "little kick" I decided to look into it. From all the different "experts" I found on the web or talked to, here is what I found..and I will let you decide for yourselves. Here is a small sample of answers I got during my search:
"Nope, turning on the head lights would be the last thing you would want to do, all it does is draw current and capacity from the battery. "
"Most fuel injected cars can be aided by leaving the ignition on for 3-5 seconds before turning the key on to the start position."
"Turning on the headlights will increase the current flow in a battery, it also consumes valuable capacity that could be used to start the cold engine; therefore, this is not recommended. For cold temperatures, externally powered temperature compensated battery "float" chargers, warmers or blankets, and engine block heaters are highly recommended if the vehicle can not be parked in a heated garage."
" A battery that's been warmed up can provide more juice than a cold battery - and having current flow warms up a battery. Whether or not switching on the lights before starting (and presumably, turning them off while starting) works, I can't say - I'd guess not, but it would depend on how long you left the light on and how much current you were drawing out of the battery.
" So, I am guessing (because again, I'm not a mechanic!) DON'T DO IT!!! Hope this helps!