Battery Charge Question

02'TrueBlue · January 29th, 2011, 02:26 PM

I'm getting tired of having to charge my car pretty much every time it sits for a couple days. I went and bought a 1 amp slow charge from autozone a while back the first time the car died so I could charge it once for cheap and forget about it but the problem is happening often now. So my question is do you think I could leave this charger on permanently when I'm not using the car or would I have to go and get a new charger with controls to stop it from over charging? The car has a viper alarm and other electronics so I'm not sure if that would help it from not over charging.. Thanks guys.

tbirdscwd · January 29th, 2011, 02:31 PM

You need to find out what is draining your battery. Your car should be able to sit for roughly a month without draining the battery..... That is of course if your battery isn't on it's last little leg

02'TrueBlue · January 29th, 2011, 02:35 PM

Well I had it tested at autozone a few weeks ago and they said it was good, just needed to be charged, and they even charged it with their charger to 100%, and it went in less than a week after that. I would start by pointing the finger at my alarm but I'm not quite sure. when I DD'd the car, it never died like this

tbirdscwd · January 29th, 2011, 04:25 PM

Well, a fully charged battery should definitely last longer than your is lasting. Culprits could be

1. Battery isn't actually able to hold a full charge
2. Alternator is not putting out as much amperage and voltage to fully charge the battery during the times you do drive it.
3. You have some sort of parasitic draw that is present with the key off

02'TrueBlue · January 29th, 2011, 04:44 PM

Well a little background:
I have an 800 Watt Amp and a 900 Watt Amp, powering subs and speakers.
I have the stock alternator, which was repaired when the diodes broke a while back and sent the camshaft sensor crazy.
I have an in-dash navigation.
I have footwell neons ran to a switch.
Annnndddd that's about it for extra electronics I can think of that could be parasitic.
The only issue is that I've had all those for a long time, and like I said, it was fine DD'd, but september I stopped driving it a lot and started having this problem. Any way I can test these things?

tbirdscwd · January 29th, 2011, 04:51 PM

You need a multi meter to start testing the stuff. All those extras are fine and should cause the problem you are having unless you wired them all directly without any switches. I'm assuming that you have the stereo stuff wired to a key on source which won't affect the car when the key is off. The neons won't be drawing any amperage with their switch off. And the in dash navigation should also be wired to come on with the key on. Do you have anything plugged into your 12v cigarette lighters/power outlets?

02'TrueBlue · January 29th, 2011, 04:59 PM

The amps are wired directly to the battery but they won't turn on without a key, would they? I had everything professionally installed, so I'd imagine it's all done right..
With a multimeter, I'd just go over wires and see if anything's getting power while the car is off, right?

02'TrueBlue · January 29th, 2011, 05:00 PM

oh and the cigarette lighter doesn't have anything in it

tbirdscwd · January 29th, 2011, 07:49 PM

Originally Posted by 02'TrueBlue

The amps are wired directly to the battery but they won't turn on without a key, would they? I had everything professionally installed, so I'd imagine it's all done right..
With a multimeter, I'd just go over wires and see if anything's getting power while the car is off, right?

Your amps are wired directly to the battery, but they shouldn't be draing any power without the car on....if they are, then that is your problem. But it sounds like you have had them in there for a while and this problem is pretty new. Have you had your new alternator tested?

casper gt · January 29th, 2011, 08:56 PM

have your battery & alt checked again, then IMO start looking at the aftermarket alarm, they are well known for causing all kinds of electrial problems & disasters.

02'TrueBlue · January 29th, 2011, 09:05 PM

Yeah I'll have the alt and battery re-tested...the only reason I ruled them out was because autozone said my battery was good when they checked and charged it (plus now that I think of it, it sat outside of the car for like 2 weeks and started right up), and the alternator was repaired over the summer. But i'll have them re-tested. The only problem with the alarm is that the shop that installed it is now gone (didn't go under, just retired after 20 something years..Classic Audio in Woodbridge, NJ) but I'm sure my new shop would have no problem checking into the problem. I was thinking about getting my auto-start bypassed by them anyway. The thing makes me set it everytime I stop the car if I want to use it. Pain in the ass!

casper gt · January 29th, 2011, 09:12 PM

Originally Posted by 02'TrueBlue

Yeah I'll have the alt and battery re-tested...the only reason I ruled them out was because autozone said my battery was good when they checked and charged it (plus now that I think of it, it sat outside of the car for like 2 weeks and started right up), and the alternator was repaired over the summer. But i'll have them re-tested. The only problem with the alarm is that the shop that installed it is now gone (didn't go under, just retired after 20 something years..Classic Audio in Woodbridge, NJ) but I'm sure my new shop would have no problem checking into the problem. I was thinking about getting my auto-start bypassed by them anyway. The thing makes me set it everytime I stop the car if I want to use it. Pain in the ass!

IMO I'd have the whole aftermarket alarm removed & tossed in the trash.

the OE Ford system is pretty much undefeatable & is easy to troubleshoot if it gives you problems.

bottom line if someone wants your car bad enough, they will just hook it up with a tow truck/etc.

tbirdscwd · January 29th, 2011, 09:17 PM

Originally Posted by 02'TrueBlue

Yeah I'll have the alt and battery re-tested...the only reason I ruled them out was because autozone said my battery was good when they checked and charged it (plus now that I think of it, it sat outside of the car for like 2 weeks and started right up), and the alternator was repaired over the summer. But i'll have them re-tested. The only problem with the alarm is that the shop that installed it is now gone (didn't go under, just retired after 20 something years..Classic Audio in Woodbridge, NJ) but I'm sure my new shop would have no problem checking into the problem. I was thinking about getting my auto-start bypassed by them anyway. The thing makes me set it everytime I stop the car if I want to use it. Pain in the ass!

BTW, who took your alternator apart and replaced your diodes? That is not exactly common practice for an auto shop anymore.

I'd have the alt tested again along with the battery. If they both check out ok, then start looking into what could be draining it. I think the alarm and the stereo could be good places to look right off the bat.

02'TrueBlue · January 29th, 2011, 09:18 PM

Yeah, now that the car sits a lot, it's kind of a waste, but when I DD'd it to high school last year I felt a lot more secure around the mexican honda drivers...they all went to auto school half the day and knew exactly what they were doing if they wanted to take whatever was in my car, or the whole car. And auto start was a life saver in winter mornings. Plus I had plans on driving it to college too where it would've been vulnerable. I was just paranoid of my nav becoming a target when I first got it lol

02'TrueBlue · January 29th, 2011, 09:20 PM

Originally Posted by tbirdscwd

BTW, who took your alternator apart and replaced your diodes? That is not exactly common practice for an auto shop anymore.

I'd have the alt tested again along with the battery. If they both check out ok, then start looking into what could be draining it. I think the alarm and the stereo could be good places to look right off the bat.

My girlfriend's dad has a friend that owns an alternator shop and just had the guy fix the broken alternator for $40 rather than getting a whole new one. So if it comes down to it, it's not a huge loss to buy a new one, but I'm pretty sure that won't be the case, I recall the car dying during the 2 or 3 days the alternator was out of the car getting repaired also...

99GT35thLE · January 30th, 2011, 08:16 AM

Batteries are funny, they can show they have voltage and still not start a car. I just replaced a month old battery that was showing 12.3 volts on my meter, took it back to NAPA and it showed good on his meter. He replaced the battery under warranty.

I couldn't even jump start my car using my truck with the old battery. Dropped in the new battery and problem was solved.

02'TrueBlue · January 30th, 2011, 08:20 AM

Yeah it's very misleading when I turn the car on, and all looks well, then I turn the key to start and it just clicks lol. I don't wanna go ahead and buy a new battery and then find out that something was just draining the old one though

mach1soldier · January 30th, 2011, 09:22 AM

Hook a volt meter up to the battery at idle and you should see 14.3 - 14.7 volts. If it is closer to 12 or 13 volts, you need to replace the alternator. This will save you taking off the alternator and dragging it into autozone.

02'TrueBlue · January 30th, 2011, 09:59 AM

Originally Posted by mach1soldier

Hook a volt meter up to the battery at idle and you should see 14.3 - 14.7 volts. If it is closer to 12 or 13 volts, you need to replace the alternator. This will save you taking off the alternator and dragging it into autozone.

Alright thanks for the advice, I'll get my hands on a volt meter and start testing

cliffyk · January 30th, 2011, 12:09 PM

Here is a link to the charging system diagnostic procedures from the shop manual.

On page 414-00-10 there is a section named Drain Tests; performing the tests provided in that section will let you determine if your car is drawing too much current when turned off (it should not be more than 50mA). If it is drawing too much power you need to pull fuses one at a time and see which one(s) reduce the current draw.

When you find those you will be able to determine which devices are continuing to draw power when they are "off"...

January 29th, 2011, 02:26 PM	#1
02'TrueBlue Enthusiast 2002 Mustang GT 13.91 @ 102.04 Join Date: Dec 2010 Location: Rahway, NJ Posts: 880 iTrader: 0 reviews	Battery Charge Question I'm getting tired of having to charge my car pretty much every time it sits for a couple days. I went and bought a 1 amp slow charge from autozone a while back the first time the car died so I could charge it once for cheap and forget about it but the problem is happening often now. So my question is do you think I could leave this charger on permanently when I'm not using the car or would I have to go and get a new charger with controls to stop it from over charging? The car has a viper alarm and other electronics so I'm not sure if that would help it from not over charging.. Thanks guys. __________________ TRUE BLUE CREW MEMBER #6

January 29th, 2011, 02:31 PM	#2
tbirdscwd MM Fanatic 2004 Mustang GT 12.88 @ 109.45 N/A Join Date: Feb 2010 Location: Davis, CA Posts: 3,417 iTrader: -1 reviews	You need to find out what is draining your battery. Your car should be able to sit for roughly a month without draining the battery..... That is of course if your battery isn't on it's last little leg __________________ Fun: 2004 Mustang GT DD: 1994 Ram 2500 Cummins 4x4 Borla "Stinger" Exhaust Vids

January 29th, 2011, 02:35 PM	#3
02'TrueBlue Enthusiast 2002 Mustang GT 13.91 @ 102.04 Join Date: Dec 2010 Location: Rahway, NJ Posts: 880 iTrader: 0 reviews	Well I had it tested at autozone a few weeks ago and they said it was good, just needed to be charged, and they even charged it with their charger to 100%, and it went in less than a week after that. I would start by pointing the finger at my alarm but I'm not quite sure. when I DD'd the car, it never died like this __________________ TRUE BLUE CREW MEMBER #6

January 29th, 2011, 04:25 PM	#4
tbirdscwd MM Fanatic 2004 Mustang GT 12.88 @ 109.45 N/A Join Date: Feb 2010 Location: Davis, CA Posts: 3,417 iTrader: -1 reviews	Well, a fully charged battery should definitely last longer than your is lasting. Culprits could be 1. Battery isn't actually able to hold a full charge 2. Alternator is not putting out as much amperage and voltage to fully charge the battery during the times you do drive it. 3. You have some sort of parasitic draw that is present with the key off __________________ Fun: 2004 Mustang GT DD: 1994 Ram 2500 Cummins 4x4 Borla "Stinger" Exhaust Vids

January 29th, 2011, 04:44 PM	#5
02'TrueBlue Enthusiast 2002 Mustang GT 13.91 @ 102.04 Join Date: Dec 2010 Location: Rahway, NJ Posts: 880 iTrader: 0 reviews	Well a little background: I have an 800 Watt Amp and a 900 Watt Amp, powering subs and speakers. I have the stock alternator, which was repaired when the diodes broke a while back and sent the camshaft sensor crazy. I have an in-dash navigation. I have footwell neons ran to a switch. Annnndddd that's about it for extra electronics I can think of that could be parasitic. The only issue is that I've had all those for a long time, and like I said, it was fine DD'd, but september I stopped driving it a lot and started having this problem. Any way I can test these things? __________________ TRUE BLUE CREW MEMBER #6

January 29th, 2011, 04:51 PM	#6
tbirdscwd MM Fanatic 2004 Mustang GT 12.88 @ 109.45 N/A Join Date: Feb 2010 Location: Davis, CA Posts: 3,417 iTrader: -1 reviews	You need a multi meter to start testing the stuff. All those extras are fine and should cause the problem you are having unless you wired them all directly without any switches. I'm assuming that you have the stereo stuff wired to a key on source which won't affect the car when the key is off. The neons won't be drawing any amperage with their switch off. And the in dash navigation should also be wired to come on with the key on. Do you have anything plugged into your 12v cigarette lighters/power outlets? __________________ Fun: 2004 Mustang GT DD: 1994 Ram 2500 Cummins 4x4 Borla "Stinger" Exhaust Vids

January 29th, 2011, 04:59 PM	#7
02'TrueBlue Enthusiast 2002 Mustang GT 13.91 @ 102.04 Join Date: Dec 2010 Location: Rahway, NJ Posts: 880 iTrader: 0 reviews	The amps are wired directly to the battery but they won't turn on without a key, would they? I had everything professionally installed, so I'd imagine it's all done right.. With a multimeter, I'd just go over wires and see if anything's getting power while the car is off, right? __________________ TRUE BLUE CREW MEMBER #6

January 29th, 2011, 05:00 PM	#8
02'TrueBlue Enthusiast 2002 Mustang GT 13.91 @ 102.04 Join Date: Dec 2010 Location: Rahway, NJ Posts: 880 iTrader: 0 reviews	oh and the cigarette lighter doesn't have anything in it __________________ TRUE BLUE CREW MEMBER #6

January 29th, 2011, 08:56 PM	#10
casper gt Moderator 2012 300a gt auto 12.10@116 Join Date: Mar 2008 Location: creighton pa Posts: 7,697 iTrader: 4 reviews	have your battery & alt checked again, then IMO start looking at the aftermarket alarm, they are well known for causing all kinds of electrial problems & disasters. __________________ MM BRACKET RACING CREW CO-FOUNDER BAMA Performance Drag Team Founder 2012 300a GT auto

January 29th, 2011, 09:05 PM	#11
02'TrueBlue Enthusiast 2002 Mustang GT 13.91 @ 102.04 Join Date: Dec 2010 Location: Rahway, NJ Posts: 880 iTrader: 0 reviews	Yeah I'll have the alt and battery re-tested...the only reason I ruled them out was because autozone said my battery was good when they checked and charged it (plus now that I think of it, it sat outside of the car for like 2 weeks and started right up), and the alternator was repaired over the summer. But i'll have them re-tested. The only problem with the alarm is that the shop that installed it is now gone (didn't go under, just retired after 20 something years..Classic Audio in Woodbridge, NJ) but I'm sure my new shop would have no problem checking into the problem. I was thinking about getting my auto-start bypassed by them anyway. The thing makes me set it everytime I stop the car if I want to use it. Pain in the ass! __________________ TRUE BLUE CREW MEMBER #6

January 29th, 2011, 09:18 PM	#14
02'TrueBlue Enthusiast 2002 Mustang GT 13.91 @ 102.04 Join Date: Dec 2010 Location: Rahway, NJ Posts: 880 iTrader: 0 reviews	Yeah, now that the car sits a lot, it's kind of a waste, but when I DD'd it to high school last year I felt a lot more secure around the mexican honda drivers...they all went to auto school half the day and knew exactly what they were doing if they wanted to take whatever was in my car, or the whole car. And auto start was a life saver in winter mornings. Plus I had plans on driving it to college too where it would've been vulnerable. I was just paranoid of my nav becoming a target when I first got it lol __________________ TRUE BLUE CREW MEMBER #6

January 30th, 2011, 08:16 AM	#16
99GT35thLE Hardcore Enthusiast 1999 GT 35th LE Join Date: Dec 2009 Location: Jacksonville, Florida Posts: 1,428 iTrader: 0 reviews	Batteries are funny, they can show they have voltage and still not start a car. I just replaced a month old battery that was showing 12.3 volts on my meter, took it back to NAPA and it showed good on his meter. He replaced the battery under warranty. I couldn't even jump start my car using my truck with the old battery. Dropped in the new battery and problem was solved. __________________ Drive it like you stole it

January 30th, 2011, 08:20 AM	#17
02'TrueBlue Enthusiast 2002 Mustang GT 13.91 @ 102.04 Join Date: Dec 2010 Location: Rahway, NJ Posts: 880 iTrader: 0 reviews	Yeah it's very misleading when I turn the car on, and all looks well, then I turn the key to start and it just clicks lol. I don't wanna go ahead and buy a new battery and then find out that something was just draining the old one though __________________ TRUE BLUE CREW MEMBER #6

January 30th, 2011, 09:22 AM	#18
mach1soldier Regular Join Date: Oct 2010 Posts: 94 iTrader: 0 reviews	Hook a volt meter up to the battery at idle and you should see 14.3 - 14.7 volts. If it is closer to 12 or 13 volts, you need to replace the alternator. This will save you taking off the alternator and dragging it into autozone. __________________ 2003 mach 1 12.7x @103 4600 stall, 4:30, slicks & skinnies, ALUM DS, VMP tune. 1996 ford thunderbird (13.02 @104) pi block, all the bolt ons minus cams, 3.73, 3800 stall.

January 30th, 2011, 12:09 PM	#20
cliffyk Hardcore Enthusiast Join Date: Feb 2007 Location: Saint Augustine, FL Posts: 1,808 iTrader: 1 reviews	Here is a link to the charging system diagnostic procedures from the shop manual. On page 414-00-10 there is a section named Drain Tests; performing the tests provided in that section will let you determine if your car is drawing too much current when turned off (it should not be more than 50mA). If it is drawing too much power you need to pull fuses one at a time and see which one(s) reduce the current draw. When you find those you will be able to determine which devices are continuing to draw power when they are "off"... __________________ -cliff knight- My Mustang 2003 GT, UPR X, 24lb/h injectors, Magnaflow, 180° stat, PP 70mm TB & plenum, DF Commando, Steeda UDPs, Ralco RZ_flywheel, RAM HDX clutch, WX EFX COPs 3.73s, 262 rwHP/305 lb-ft. Flex-fuel: burns gas and rubber...

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