car off, still drawing power?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=39114
Printed Date: July 03, 2025 at 8:40 AM
Topic: car off, still drawing power?
Posted By: /R7
Subject: car off, still drawing power?
Date Posted: September 14, 2004 at 12:20 AM
tonight i went over to a friends house to listen to him n his band play, while i was there i had to follow one of my friends back to his place so he could drop off his truck, after that my car sat, with the keys out of the ignition for about 30-40mins, we could say 1hr just to be cautious.
when we were leaving, the car wouldnt even turn over, headlights werent even on. so between getting a vehicle to boost me and sitting around, i completely disconnected my amp from any power (aside from EQ RCA's to the amp). after about 10mins before we got it boosted, i drove around w/ my friends noticing my headlights would flicker, note i had turned the music off, but the EQ is always on i believe (no power button). we went and chilled for a bit in park, and i had turned my lights on and off a few times after having sat with the car revving for over 5minutes, after trying to turn the headlights on for the third time, my car just died, quit, and when i tried to start it, it wouldnt even turn over. took another 15mins till i got home after calling for a boost,, and now its sitting in the driveway with the charger on it.
My question is, what could cause a constent draw from the battery after the car is off, any possibilities would suffice, i'll look into anything.
my only guess is, maybe, the EQ when the car is off, but even that kinda baffles me, unless one of the wires on the eq either fell off or isnt making a solid connection, but i would hope the installer last friday installed it securely.
BTW - i've had my car running on and off listening to alot of tunes (hours apon hours since its been installed), after killing the battery one night after drinking and forgetting to turn the headlights off, other than that the car hasnt showed any problems at all ;/
ideas and suggestions would be most welcome, thanks.
Replies:
Posted By: stevdart
Date Posted: September 14, 2004 at 12:40 AM
Not necessarily a power drain unless you've tested it. Could be that the battery is just shot. They lose a lot of (future) life when you let them go dead. Keep all the wiring hooked up as you had it...buy and install a new battery and test amp flow with everything off. There's a lotta drain on the car's electrical system when you put in a powerful sound system. So you pay when you leave the headlights burning.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: Ravendarat
Date Posted: September 14, 2004 at 12:48 AM
Could be a bad altenator as well, or at least a bad connection at the altenator that is causing it to not charge properly, I doubt its the stereo.
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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer
Posted By: /R7
Date Posted: September 14, 2004 at 7:55 AM
yeh im hoping its neither the alt (replaced it a year+ before even touching the cars stereo), or the battery, but if im willing to pay out the ass for sound equipment i best be ready to pay for the juice to keep the tunes goin too.
i've let the car sit overnight on the charger so if its shot to hell today i'll look @ a new battery and see if anything changes.
Thanks guys
Posted By: fuseblower
Date Posted: September 14, 2004 at 9:32 AM
If your car just died on you when you turned the lights on it sounds like you have a weak alternator. With your car running disconnect your negative battery post. Most of the time your car will kills if your alternator is weak since a car runs utilizing your alternator as well as your battery.
Posted By: chevyman26
Date Posted: September 14, 2004 at 11:11 AM
You could also just bring the battery and/or alt. to just about any parts store and have them test it for you. They'll be more than happy to if it means selling you a new part! BTW - How big is your alt. and how many watts is your system? ------------- You'd better get me out of this lord... or else you'll have me to deal with. -- Hunter S. Thompson "F.A.L.I.L.V."
Posted By: Alpine Guy
Date Posted: September 14, 2004 at 2:51 PM
that happend to me, , its what happends when your alt dies. You get a boost and your good to run for 15-20 min with no accessories on since it takes nothing to run the computer, , ,but once you turn the air, or the light on it takes everything left in the battery and leaves nothing for the computer so your car dies. I can almost guarantee that your stereo was too much for the little alt and it probably blew from heat. Don't do the pulling the (-) trick that fuseblower suggested, , you cannot do it on todays vehicles without 95% risk of damage to the computer system. It was a good trick back in the day before electronics ran out vehicles. If you said that to a mechanic nowadays he'd slap you silly, , , not to mention you'd prolly fry your deck, and amps in the process. Just simply bring your battery in to get checked, and bring your car in to get load tested. Those are you 2 least expensive avenues. Iv gone through it hundreds of times for customers and my vehicles. ------------- 2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
Posted By: forbidden
Date Posted: September 14, 2004 at 2:58 PM
Make sure the damn terminals are tight on the battery and the battery to chassis connection. If they are fine, my bet is a bad battery or an alternator on it's way to the old parts home in the sky.
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Top Secret, I can tell you but then my wife will kill me.
Posted By: Alpine Guy
Date Posted: September 14, 2004 at 4:10 PM
yup, always check the easy, things first, , there usually the dumb things you would never think of. If you battery has lots of powder around the terminals clean them up and put sum dielectric grease to prevent more corosion. ------------- 2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
Posted By: jeffchilcott
Date Posted: September 14, 2004 at 6:54 PM
if you have a dmm. you can check to see if your alt is putting out any juice at all
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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place
Posted By: /R7
Date Posted: September 14, 2004 at 7:18 PM
if it comes to a new battery, is it recommended to buy one of the 200$+ yellow top batteries, or will a battery from crappytire or a parts shop work fine?
and if its my alt, 120amp alt should work fine shouldnt it?
i plan on putting at 'most', one more amp into the car, it will be a class D amp, and for subs, but i dont know how many watts it will push or anything, but it will between 800-1200 watts
if the car dont start tonight after leaving it on a charger (found another one to use), then ima scrap the batt and hope thats my only problem :/
not ruling out alt though until a new battery shows the same problem.
Posted By: Ravendarat
Date Posted: September 14, 2004 at 7:29 PM
Before you get a new battery get the damn thing tested, like someone else said most parts source or other automotive shops can and will test the battery and altenator for free so utilize it. Why spend a couple hundred bucks on a battery when its the altenator that could be screwed. ------------- double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer
Posted By: Alpine Guy
Date Posted: September 14, 2004 at 8:54 PM
if you do get a new batt ( if thats what you need) get the new motomaster battery, , aparently its made by optima, , it looks just like it but black.
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2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
Posted By: thapimpfromchi
Date Posted: September 14, 2004 at 9:49 PM
damn, forbidden beat me to the battery terminals. anyways, u can also check the alt, if u dont have a dmm, with a screw driver, hammer, wrench, anything metal. turn the car on, find the alt, on the back half, (the side that does not have the belt going to it) place the metal tool there, if u feel any magnetic pull, ur alt is fine. if there is none, or very weak, ur alt is dying or dead.
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1990 Honda Civic HB:
Clarion DXZ545MP H.U.
2- 6.5" Power Acoustik interiors
Diamond Audio 600.1 amp
Diamond Audio 15" M6MKII
Pyramid PB881X 4 CH. Amp
Posted By: Ravendarat
Date Posted: September 14, 2004 at 9:51 PM
Thats a different trick, I have never heard of that one before
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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer
Posted By: /R7
Date Posted: September 15, 2004 at 12:03 AM
the alt was juicing my batt with 14.7 or .17 volts,
my dad (long time car mechanic, back in the day) did his various tests, i may not trust his judgement on car audio specifically but when it comes to the mechanics of it (i cant deny either, that his advice about what im putting in my car sounds very reasonable and makes me question what i do based on what i've read) i have dont deny it. i'll see if i can mention to him about picking up a specific one, if theres the selection where he'll prolly buy it at.
even if its not the battery,
- starting the car not jumped wont even get a response, aside from all electronics dimming.
- 3hrs of charging, didnt even change the result of the above.
kind of indicates the battery isnt doing its job, even if its not the real problem.
it seems like it refuses to charge at all.
anyways, i appreciate all the responses, i almost remember hearing that when i was younger, or having some instance of that happening in my life. but definitely never would have thought of it had i tried to think of a way. thanks for the tip :-)
Posted By: chevyman26
Date Posted: September 15, 2004 at 12:20 AM
/R7]if wrote:
it comes to a new battery, is it recommended to buy one of the 200$+ yellow top batteries, or will a battery from crappytire or a parts shop work fine?
and if its my alt, 120amp alt should work fine shouldnt it?
i plan on putting at 'most', one more amp into the car, it will be a class D amp, and for subs, but i dont know how many watts it will push or anything, but it will between 800-1200 watts
O.k. - if I'm not mistaken the yellow tops are deep cycle, so you wouldn't want to use that as the car's main batt. If you go that route, go with a red top, but any decent "regular" batt. should be fine. Next: 800-1200 RMS for the one amp? Then how many watts for the other amps? You more than likely need a much larger alt. Of that 120 amps your car probably uses about 70-75 of those during normal operation leaving around 45 for your stereo. 45 amps at best could run about 600 watts of stereo. So if I were you I'd be looking for around a 240 or 260 amp alt. when you add that class D. Finally: As said before - connections, connections, connections. Double and triple check all your connections. Clean the posts and terminals even if they don't look like they need it. If it's top post, measure any resistance between the post and the back end of the terminal. The resistance should be absolutely minimal. You can also check if there is a drain on your batt. when the car is off by disconnecting one of the terminals (most mechanics do the pos. for this test, but it really doesn't matter) and place a DMM set to amps or any ammeter in series between the batt. and the disconnected terminal. A draw of .5-.7 amps is normal because of clocks and other memory holding devices, but anything higher is abnormal. If you see a high draw, start disconnecting stereo equipment one by one and re-checking. O.k - one more thing - just a thought - is the car an older (early 90's and back) Ford with an external voltage regulator? It would be a little black and silver (or the color of the dust in your area, lol) box with a dozen or so wires running into it mounted on the driver side wheelwell under the hood, probably says "motorcraft" on top. When these go out they will kill your batt. real quick when the car is off, among other strange things. If it is you will see a minimum of 7 amp draw on the batt. using the above test. If it's not a Ford, then just nevermind this.. Sorry for the long post - just got off work and I'm still in "explain it" mode. I've been thinkin' about this one all day... ------------- You'd better get me out of this lord... or else you'll have me to deal with. -- Hunter S. Thompson "F.A.L.I.L.V."
Posted By: /R7
Date Posted: September 15, 2004 at 12:36 AM
thats kool man, a person learns more when someone actually has the time to explain things.
anyways, my dad tested the car with everything supposed to be off, and using a tester light (screw driver/light tool), no draw was being shown while the hood was down, pulling the hood up caused a draw, thats another thing he did.
Posted By: chevyman26
Date Posted: September 15, 2004 at 12:36 AM
Sorry - couple more things - As Alpine said: Do not do the (-) disconnect trick unless the car is at least older than like an '81. And if you do the amp draw test and disconnecting the stereo doesn't get rid of the draw - open up the fusebox and start pulling fuses 1 by 1 untill the draw is gone, then check your manual to see what is all on that fuse. ------------- You'd better get me out of this lord... or else you'll have me to deal with. -- Hunter S. Thompson "F.A.L.I.L.V."
Posted By: chevyman26
Date Posted: September 15, 2004 at 12:42 AM
Ok, well, I didn't see your reply before I finished typing. Anyways good luck and if any thing else comes up let us know. BTW - what kind of car is it?
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You'd better get me out of this lord... or else you'll have me to deal with. -- Hunter S. Thompson "F.A.L.I.L.V."
Posted By: mobile E
Date Posted: September 15, 2004 at 1:08 AM
i had this happen to me like 3 or 4 times ... it happens if something moves around in youre trunk and the remote turn on wire touches the neg ground wire.... this runs the amp ..until the amp runs the battery dry... Make shure that that positive remote turn on lead stays away from the neg... 
------------- everything stolen :(
Workin on a new system :)
Peace in the middle east
Posted By: fuseblower
Date Posted: September 15, 2004 at 8:44 AM
Alpine, I didn't think about the possibility of messing up the cars computer but good catch. I started to think about different scenarios that could take place under your hood. So, I did a little research. Here is an article I found. And when you think about it, removing the batteries post is just like a battery dieing out. https://www.mmxpress.com/technical/electsys.htm
Posted By: Alpine Guy
Date Posted: September 15, 2004 at 10:33 AM
Yup, , when you remove then positive post then its not that bad, , but in your first post you said remove the negative, which would be horrible.
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2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
Posted By: /R7
Date Posted: September 15, 2004 at 1:14 PM
@ mobile E, that is a possibility, i had removed my amps power connections, and had them spread out on the trunk without having taped them over, wasnt for too long, maybe 10minutes of moving things around, but even in that time period i dont know if anything touched.
Been waiting to get my battery into my car, its sitting in the back of my dads truck and i cant find him. we'll see if its connections or battery or something else once i get the battery in.
@Chevy, should have answered this in my last post, my car fortunately isnt a ford, its a 91 buick, thanks though :-)
Posted By: fuseblower
Date Posted: September 15, 2004 at 1:33 PM
Thanks for bringing that up Alpine Guy. Hate to have messed up someone's car by ignorance... 
Posted By: ziggy8882
Date Posted: September 15, 2004 at 9:23 PM
you might need a high output alternator if you're running too much amperage from your system, 140-160 amp alternator would be good
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ziggles
Posted By: /R7
Date Posted: September 15, 2004 at 10:59 PM
new battery, works great :-)
i'll give it a week and if i see signs of death in this battery i'll start pluckin hairs from my head -_-
Posted By: Teken
Date Posted: September 15, 2004 at 11:12 PM
thapimpfromchi wrote:
if u feel any magnetic pull, ur alt is fine. if there is none, or very weak, ur alt is dying or dead.
That is wrong . . .
Posted By: Teken
Date Posted: September 15, 2004 at 11:15 PM
Alpine Guy wrote:
get the new motomaster battery, , aparently its made by optima, , it looks just like it but black.
That would be incorrect. The design is patented, and is being used by Excide with royalties being payed for said use.
It is not made, or manufactured by Optima or its parent company. Excide makes the batteries themselves.
Posted By: Teken
Date Posted: September 15, 2004 at 11:22 PM
chevyman26 wrote:
O.k. - if I'm not mistaken the yellow tops are deep cycle, so you wouldn't want to use that as the car's main batt.
That would be wrong . . . The Yellow top is designed to be a SLI battery. It is not made like a ordinary deep cycle battery which you see being sold by every John, Dick, and Harry . . .
If the vehicles electrical will see extreme depeletions of the batteries cells at any given point. The Red Top will die like any other SLI battery.
It is not intended or designed to endure prolonged, or deep cycles.
End of story . . .
Posted By: Teken
Date Posted: September 15, 2004 at 11:27 PM
Ravendarat wrote:
Before you get a new battery get the damn thing tested, like someone else said most parts source or other automotive shops can and will test the battery and altenator for free so utilize it. Why spend a couple hundred bucks on a battery when its the altenator that could be screwed.
This is the only sound advice I have read thus far, other than from Forbidden.
People are simply guessing, or relying on part knowledge of how to trouble shoot this.
An AVR test using a Midtronics tool, along with a Avalanch diode check will tell you 100% as to the current state of your electrical system.
There will not be any guessing as to what part is dead, failing or faulty.
Get it done, and move on . . . Otherwise you are wasting your time, and precious money that I am sure you do not have .
The End . . .
EVIL Teken . . .
Posted By: Teken
Date Posted: September 15, 2004 at 11:36 PM
/R7]an wrote:
using a tester light (screw driver/light tool), no draw was being shown while the hood was down, pulling the hood up caused a draw, thats another thing he did.
That would not tell you the current draw, that would simply tell you that there is voltage being dropped.
A DMM is required to measure the parasitic load current being drawn down, a test light cannot tell you this with any numerical value to have reference to.
Just because the light comes on or off, does this tell you how much voltage / current is being consumed / dropped??
EVIL Teken . . .
Posted By: Alpine Guy
Date Posted: September 16, 2004 at 11:36 PM
wow, , just rippen it up eh
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2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
Posted By: /R7
Date Posted: September 17, 2004 at 1:44 AM
teken before you jump all over me, i simply said we used it to test if current was still being drained he wanted to know if a ground was elsewhere, or something, im no mechanic but it helped him in some way. the amount or value it held was not important, hence the use of the light, we could have simply used either one of our dmms to figure what we needed. im not saying your incorrect, but your feeling to rip at me was no more important than the self written signature "EVIL Teken . . ."
kool
Posted By: Teken
Date Posted: September 17, 2004 at 4:33 PM
/R7] t wrote:
ken before you jump all over me
I was not jumping on you or anyone for that matter, if that came across that way I apologise.
/R7]bu wrote:
your feeling to rip at me was no more important than the self written signature "EVIL Teken . . ."
This is my call sign . . . It has been so, for over 25 years on almost all the forums I am a member, or moderator.
The bottom line is this, if I see information that is not accurate, I will take the time to address it, and clarify it for all members.
That is the whole point of this forum, to besotowe the facts, and not half truths, or misinformation.
Unlike others, I do not take anything on any forum personaly.
Why??? Because they *people* have no direct affect on me in the real world. That is what everyone should remember.
End Of story
EVIL Teken . . .
Posted By: thapimpfromchi
Date Posted: September 17, 2004 at 7:00 PM
hey teken, i dunno if its a typo or im just dumb, but what on earth is "besotowe"???
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1990 Honda Civic HB:
Clarion DXZ545MP H.U.
2- 6.5" Power Acoustik interiors
Diamond Audio 600.1 amp
Diamond Audio 15" M6MKII
Pyramid PB881X 4 CH. Amp
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