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  #1  
Old 12-20-2011, 04:11 PM
Johnny L.A. Johnny L.A. is offline
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Car battery, interior light. How long?

I replaced the battery in my Jeep. Last week I had a new ignition switch put in, as well as had other maintenance performed. The roomie was going to use the Jeep today, and it was dead.

I put the charger on, and she said one of the interior lights was lit. I think she used the Jeep Sunday. Or maybe it was Saturday. I don't remember. Apparently she'd turned on one of the overhead lights and forgot to turn it off.

Would that really run down the battery between then and now? Or is it possible I have a 'leak' somewhere?
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  #2  
Old 12-20-2011, 04:26 PM
LSLGuy LSLGuy is offline
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I've drained the healthy battery of a daily driver car all the way down to dead over just a single night with the interior cab lights on.

These new-fangled cars where the interior lights stay on for a couple minutes after you get out are not always helpful; they camoflage the fact you've left the dome lights on.

Last edited by LSLGuy; 12-20-2011 at 04:28 PM..
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  #3  
Old 12-20-2011, 04:28 PM
dolphinboy dolphinboy is offline
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Quote:
Originally Posted by LSLGuy View Post
I've drained the healthy battery of a daily driver car all the way down to dead over just a single night with the interior cab lights on.
I have seen that too, but it depends at least to some extent on the strength of the battery.
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Old 12-20-2011, 04:30 PM
engineer_comp_geek engineer_comp_geek is offline
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Oh yeah, that will kill it.

Figure maybe 50 amp-hours for the battery and maybe a 1 amp drain and that's enough to completely drain the battery flat in 2 days.

A bigger battery may have a bit more capacity than that, and your particular light may have more or less of a current draw than that, but generally speaking, most cars will have their battery killed in one to three days if the overhead light is left on.
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  #5  
Old 12-20-2011, 04:32 PM
blondebear blondebear is offline
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I've had my cabin light on in my Mazda 3 overnight a couple of times and it still started up fine in the morning.
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  #6  
Old 12-20-2011, 06:09 PM
jz78817 jz78817 is offline
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Originally Posted by blondebear View Post
I've had my cabin light on in my Mazda 3 overnight a couple of times and it still started up fine in the morning.
You sure it was actually on all night? Lots of cars will kill the lights if left on for more than about 10 minutes.
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  #7  
Old 12-20-2011, 06:20 PM
Johnny L.A. Johnny L.A. is offline
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The Jeep is a '99, and I don't think it's smart enough to turn its lights off.

I just started it. It will start, but you have to keep the accelerator pressed or it will die. I'll keep the charger on for another 4-1/2 or 5 hours, and button it up before I go to bed.
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  #8  
Old 12-20-2011, 07:01 PM
aceplace57 aceplace57 is online now
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Interior lights on cars are just plain evil. They'll drain a charged battery easily within four hours. Headlights will drain a battery in under 2 hours.

I've gotten burned so many times leaving my interior light on. I've made a firm policy to never turn them on with the switch. I always open a door. It's just too easy to forget and not turn the switch off.

Last edited by aceplace57; 12-20-2011 at 07:02 PM..
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  #9  
Old 12-21-2011, 06:59 AM
Pine Fresh Scent Pine Fresh Scent is offline
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Just wanted to add that I learned the hard way to pull the circuit breaker to the interior light before taking the doors off my Jeep. There's a little push-button sensor on the door frame to tell the Jeep when the door's closed and to turn off the dome light.

"Why won't this stupid battery hold a charge? Oooh, that's why"
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  #10  
Old 12-21-2011, 08:28 AM
Soylent Juicy Soylent Juicy is offline
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I have a 2000 Jeep TJ and when I first got it a couple of times the battery drained after not being driven for a couple of days (like if I was away on vacation.) Long story short, I finally realized (with the help of the Jeepkings message board) that I was turning the key all the way to the "ACC" position when turning off the ignition and the key was still pulling out. No wonder the radio would always pop back on.

It took about 2 days of not being driven (to recharge the battery I guess) until the battery fully died.
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  #11  
Old 12-21-2011, 10:48 AM
Lightnin' Lightnin' is offline
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Quote:
Originally Posted by aceplace57 View Post
Interior lights on cars are just plain evil. They'll drain a charged battery easily within four hours.
I replaced all of the dome and interior lights in my Honda Element with LEDs. They're much more energy efficient, last longer, and are much brighter. I love 'em.
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  #12  
Old 12-21-2011, 11:11 AM
Really Not All That Bright Really Not All That Bright is offline
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Quote:
Originally Posted by Johnny L.A. View Post
I replaced the battery in my Jeep. Last week I had a new ignition switch put in, as well as had other maintenance performed. The roomie was going to use the Jeep today, and it was dead.
When did you replace the battery? You might not have driven it enough since to fully charge the new one.
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  #13  
Old 12-21-2011, 12:38 PM
Earl Snake-Hips Tucker Earl Snake-Hips Tucker is offline
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Quote:
Originally Posted by LSLGuy View Post
I've drained the healthy battery of a daily driver car all the way down to dead over just a single night with the interior cab lights on.
And, similarly, I've left one on all night with no ill effects.
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  #14  
Old 12-21-2011, 02:59 PM
Rachellelogram Rachellelogram is offline
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Around 2005ish, I parked my 198x Celica at a family member's wedding and left the dome light on. A mere 2 hours later, I needed a jump. I suppose it depends on the battery--that car was an old piece of crap. I still have no idea how old the battery was.
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  #15  
Old 12-21-2011, 03:06 PM
Skald the Rhymer Skald the Rhymer is offline
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Quote:
Originally Posted by aceplace57 View Post
Interior lights on cars are just plain evil. They'll drain a charged battery easily within four hours. Headlights will drain a battery in under 2 hours.

I've gotten burned so many times leaving my interior light on. I've made a firm policy to never turn them on with the switch. I always open a door. It's just too easy to forget and not turn the switch off.
I think (but am not sure and cannot check) that my 2000 Saturn SW would not alert me with a double beep if I tried to lock it via remote and the interior light was on.
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  #16  
Old 12-21-2011, 08:38 PM
Johnny L.A. Johnny L.A. is offline
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Quote:
Originally Posted by Really Not All That Bright View Post
When did you replace the battery? You might not have driven it enough since to fully charge the new one.
I replaced it over Thanksgiving, I think. And no, the Jeep hadn't been driven much. But the battery was fully charged when I bought it. (I asked several times.)
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  #17  
Old 12-21-2011, 10:32 PM
Fubaya Fubaya is offline
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I've had cars with the dome lights on all night be fine, and I've had cars go dead in less than an hour while I was cleaning or working on them and left the doors open.

Quote:
Originally Posted by Pine Fresh Scent View Post
Just wanted to add that I learned the hard way to pull the circuit breaker to the interior light before taking the doors off my Jeep. There's a little push-button sensor on the door frame to tell the Jeep when the door's closed and to turn off the dome light.

"Why won't this stupid battery hold a charge? Oooh, that's why"
Fuse #3? I laugh my butt off because they actually sell little $20 doo-dads to hold the sensor down when you take the doors off, or you can pull the fuse in even less time for free.

edit: just noticed this:

Quote:
Originally Posted by Johnny L.A. View Post
I just started it. It will start, but you have to keep the accelerator pressed or it will die. I'll keep the charger on for another 4-1/2 or 5 hours, and button it up before I go to bed.
It may not charge. A drained battery should stay running, having to keep the gas pressed is a symptom of a bad battery. I've had that happen twice in my Jeep.

Last edited by Fubaya; 12-21-2011 at 10:37 PM..
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  #18  
Old 12-22-2011, 12:47 AM
Hail Ants Hail Ants is offline
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Quote:
Originally Posted by LSLGuy View Post
These new-fangled cars where the interior lights stay on for a couple minutes after you get out are not always helpful; they camoflage the fact you've left the dome lights on.
But the thing is most of these 'new-fangled' cars also turn any & all interior lights off after about 15 minutes from the time the key gets pulled out. They'll even do it if you're sitting there with the door open (it obviously doesn't know you're there, just that the door might be ajar). My last two, '95 & '04 Pathfinders, do this.

Oh, and yes, leaving just the dome light on overnight can kill a car's battery.

Last edited by Hail Ants; 12-22-2011 at 12:48 AM..
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  #19  
Old 12-22-2011, 11:15 AM
LSLGuy LSLGuy is offline
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Quote:
Originally Posted by Hail Ants View Post
Quote:
Originally Posted by LSLGuy View Post
These new-fangled cars where the interior lights stay on for a couple minutes after you get out are not always helpful; they camoflage the fact you've left the dome lights on.
But the thing is most of these 'new-fangled' cars also turn any & all interior lights off after about 15 minutes from the time the key gets pulled out. They'll even do it if you're sitting there with the door open (it obviously doesn't know you're there, just that the door might be ajar). My last two, '95 & '04 Pathfinders, do this.
...
And my wife's '04 Jeep Liberty doesn't do this. Ask me how I know ;-)

I agree that some cars are smart enough to do that. But not all & it's not obvious which are which. Hence my caveat "... are not always helpful".

Jeep makes a bit of a fetish of not including all the latest & greatest convenience fetures in their products. As the OP is (re-)discovering.
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  #20  
Old 12-22-2011, 04:08 PM
Hail Ants Hail Ants is offline
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It's a pretty stupid thing for the car makers not to do, because it's all controlled via the car's computer, having the dome light stay on after you get in, having it slowly dim-off, having it come on when you press the keyless entry to unlock etc. Which means it's just a matter of some software code to make it always time-out and not kill your battery...
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  #21  
Old 12-23-2011, 08:24 AM
Johnny L.A. Johnny L.A. is offline
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My Prius does that. I think the Jeep's headlights will go off after an interval when the engine is turned off, but I'm not sure. But not the interior lights.

It was instilled in me early on that all electricals are turned off before shutting off the engine. My first car didn't have an accessory position on the switch, so the radio was wired such that it could be turned on without the key. Dad's Skyhawk didn't have an avionics master switch, so I'd go 'Off, off, off, off, off, [mixture idle cut-off], mags, master' when I shut down. (The plane I've been flying does have a master avionics switch, and it always seems I'm forgetting something when I shut down even though I'm not.) So I don't know if the Jeep shuts its headlights off. I should try it sometime.
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