Some things still are connected in the START mode but like you stated, there are a number of accessories that are cut off.

But doesn't the antenna motor pulling the antenna down use as at least as much energy/battery as leaving the radio on?

 

Better to turn it - and lights and windshield wipers and heater fans - off when you turn off the car, or at least make sure they're off before you start the car, no?

But doesn't the antenna motor pulling the antenna down use as at least as much energy/battery as leaving the radio on?

 

Better to turn it - and lights and windshield wipers and heater fans - off when you turn off the car, or at least make sure they're off before you start the car, no?

 

it's a little like your weight. if you have been gaining 2-3 pounds a year for the last 10 years and now you can't touch your toes then an exercise program may be in order. but if you can still wear the suit you got married in then, well, no problem.

 

if the car starts, then all is good. if it doesn't, well then maybe you need to to start an exercise program.

 

.

john, your clever reply is a little too cryptic for me. I don't have a weight problem, but I did have a question about battery drain...

john, your clever reply is a little too cryptic for me. I don't have a weight problem, but I did have a question about battery drain...

 

in general these cars start fine with everything on, they are designed to. if you have a starting problem it is not simply because you have everything on. it's something else. turning things off before you start the car may get you home but it is not a long term solution to a starting problem.

in general these cars start fine with everything on, they are designed to. if you have a starting problem it is not simply because you have everything on. it's something else. turning things off before you start the car may get you home but it is not a long term solution to a starting problem.

 

So in the absence of a "starting problem" you see no advantage to preventing a big drain on the battery each time you start it up by having headlights, wipers, AC and radio already turned on?

 

Wouldn't it prolong battery life to NOT do this?

No, it won't prolong battery life to turn everything off. The reason is that when the key is in the start position, the accessory circuit is disconnected. So in the start position, there are really only 3 things drawing power. They are the starter, the ignition coil(s) and the ECM/TCM/BCM. Headlights go off, AC clutch disengages (or rather it just doesn't engage as it is magnetic and has to be energized to engage in the first place), radio goes off, blower motor goes off, rear defrost goes off, etc.

a hammer can dissable DRL too.. or if your not willing to use a hammer..maybe a bat?

No, it won't prolong battery life to turn everything off. The reason is that when the key is in the start position, the accessory circuit is disconnected. So in the start position, there are really only 3 things drawing power. They are the starter, the ignition coil(s) and the ECM/TCM/BCM. Headlights go off, AC clutch disengages (or rather it just doesn't engage as it is magnetic and has to be energized to engage in the first place), radio goes off, blower motor goes off, rear defrost goes off, etc.

 

I'm almost ready to stop flogging this dead horse , but don't some of these things USE power from the battery while they're powering down, such as the power antenna?

 

And finally, when you turn the key to the ON position but not yet to the START position, all of the accessories you left on when you turned off the car come back to life, don't they? Isn't that a big (unnecessary) drain just before you make another big draw by turning the key to Start?

I'm almost ready to stop flogging this dead horse , but don't some of these things USE power from the battery while they're powering down, such as the power antenna?

 

And finally, when you turn the key to the ON position but not yet to the START position, all of the accessories you left on when you turned off the car come back to life, don't they? Isn't that a big (unnecessary) drain just before you make another big draw by turning the key to Start?

 

The drain, even with lots left on, would be small compared to the starter current. If it were to make a difference for that start, or to the batteries life, the battery would already be so far down the path to needing replacement that it's going to fail soon in any case.

 

I wonder if applying a smaller current before the big current might actually be good for a lead-acid battery? There's some interesting chemistry that goes on in those things.

 

 

Dave

So actually, one SHOULD leave lots of accessories on, sort of as an early-warning system that their battery is about to fail! ;-)

So that they won't be stranded at a trailhead somewhere after having parked their car in the middle of nowhere while they backpacked for a week...

The best thing you can do to prevent an unexpected electrical problem while on the road or the car is parked is to make sure the charging system and battery are in good shape and the connections to the battery are clean and sealed. Have the system load tested if you think there is a problem and check for parasitic current drains. If the current drain on the battery is more than 50 milliamps (typical is about 25 ma.) while parked then you should look for a problem. If things are ok there then you can park your car for a month and still have plenty of starting capacity.

 

Worrying about what accessories are on while starting the car isn't necessary. If the capacity of the battery is so low that they make a difference you have trouble regardless.

Obviously there are no military members in this forum. When approaching the Gatehouse of a military installation, the rule is to turn off your lights, if for no other reason than aiding the Guard in identifying you. Automakers have seen to it that this rule is impossible to enforce. YES, there should be a way to turn DRLs off, even if restricted to a very slow speed or very short distance. Some automakers have already realized the need for such a feature.

Obviously there are no military members in this forum. When approaching the Gatehouse of a military installation, the rule is to turn off your lights, if for no other reason than aiding the Guard in identifying you. Automakers have seen to it that this rule is impossible to enforce. YES, there should be a way to turn DRLs off, even if restricted to a very slow speed or very short distance. Some automakers have already realized the need for such a feature.

 

You can pull up slightly on the E-brake, as soon as it comes off the stop the DRLs turn off on most models.

 

Dave