Charging issues
12-21-2009, 04:00 PM
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Charging issues
I need help Fast.THis site abe and bleeder has helped me alot lol.OK heres the problem My 93 4runner has Been dying its got a new battery in it.The guage in the cab is showing that its overcharging when i roll windows up,turn headlight on and sfuff like that the needle shows normal.I dont know if this helps i dont know alot about trucks and not anything about batteries alternators ect.I have an amp hooked up with out a power cap just to put that out there.anything will help.Thanks
12-21-2009, 05:03 PM
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You need to be specific...by 'dying do you mean engine cuts off, battery discharging, or running rough ?
Get a multimeter if you don't have one and do some voltage checks of the charging system. I can't realy say anything more without knowing what the exact problem is.
Get a multimeter if you don't have one and do some voltage checks of the charging system. I can't realy say anything more without knowing what the exact problem is.
12-21-2009, 09:08 PM
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not really no...for any electrical troubleshooting you will need a multimeter. They are probably the most versatile tool you can own so its worth the 15 bucks haha.
Your first step is to confirm the alternator charge output. A faulty regulator can cause output to be all over the place. A high output will boil the battery and reduce its life, even killing it fairly instantly depending on how extreme the overcharge is. To check alternator output it is simply a matter of voltage checking (using a multimeter) across the battery terminals with the alternator on. If the alternator is charging correctly you should see something around 14V.
It sounds to me like you have a parasite draw, my suspect is the amp assuming you installed it and you felt it important enough to mention in your OP. Make sure that your amp is NOT on all the time visually (look for status lights). If it is on all the time you have found your problem. If its not your parasite draw is coming from somewhere else. Fortunately there is an easy way to find parasite draws. I couldn't be bothered writing the procedure but the link below explains it for you. Just make sure you resistance check first (in case there is a short) and ensure your battery is at good charge (this test wont be acurate without a properly charged battery).
http://flashoffroad.com/electrical/B...teryDrain.html
I know you probably have never done any of this before, but if you want to fix this yourself it is time to get familiar with a DMM. I suggest googling some sites that will get you familiar with the basic and advanced things you can do with a DMM. Learning how to use one also gives you a pretty good knowledge of electrical circuits.
Your first step is to confirm the alternator charge output. A faulty regulator can cause output to be all over the place. A high output will boil the battery and reduce its life, even killing it fairly instantly depending on how extreme the overcharge is. To check alternator output it is simply a matter of voltage checking (using a multimeter) across the battery terminals with the alternator on. If the alternator is charging correctly you should see something around 14V.
It sounds to me like you have a parasite draw, my suspect is the amp assuming you installed it and you felt it important enough to mention in your OP. Make sure that your amp is NOT on all the time visually (look for status lights). If it is on all the time you have found your problem. If its not your parasite draw is coming from somewhere else. Fortunately there is an easy way to find parasite draws. I couldn't be bothered writing the procedure but the link below explains it for you. Just make sure you resistance check first (in case there is a short) and ensure your battery is at good charge (this test wont be acurate without a properly charged battery).
http://flashoffroad.com/electrical/B...teryDrain.html
I know you probably have never done any of this before, but if you want to fix this yourself it is time to get familiar with a DMM. I suggest googling some sites that will get you familiar with the basic and advanced things you can do with a DMM. Learning how to use one also gives you a pretty good knowledge of electrical circuits.
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12-24-2009, 09:06 PM
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Buy a manual for your truck - or get one from your library. It will tell you how to test the charging system and it even comes with pictures.
Sears has good digital multimeters for less than 10 bucks. You may also want a few paperclips and maybe four feet of wire handy, though if its not a parasitic drain then you probably will only need the multimeter and included leads.
You say the battery goes dead after a few days of sitting so it may be a parasitic drain such as the glovebox light staying on or your amp could even be drawing power when it is supposed to be off.
Start by testing the charging system though.
Check the battery with the truck off after a drive.
Check the battery again after it sits for several hours or even over night.
Check the battery voltage with the truck running, this number is the voltage being fed to the battery from the alternator - between 14 to 15 volts is normal but don't fret if it is in the 13 volt range.
12.6 volts is fully charged.
Below 9 volts is a dead battery.
Start there and let us know what you come up with.
Sears has good digital multimeters for less than 10 bucks. You may also want a few paperclips and maybe four feet of wire handy, though if its not a parasitic drain then you probably will only need the multimeter and included leads.
You say the battery goes dead after a few days of sitting so it may be a parasitic drain such as the glovebox light staying on or your amp could even be drawing power when it is supposed to be off.
Start by testing the charging system though.
Check the battery with the truck off after a drive.
Check the battery again after it sits for several hours or even over night.
Check the battery voltage with the truck running, this number is the voltage being fed to the battery from the alternator - between 14 to 15 volts is normal but don't fret if it is in the 13 volt range.
12.6 volts is fully charged.
Below 9 volts is a dead battery.
Start there and let us know what you come up with.
12-24-2009, 09:08 PM
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Great info there for the noobs to automotive electrical diagnosis
Def read that
10-29-2010, 06:33 AM
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Also, an alternator going bad can cause a short that drains the battery when not running.
Last edited by TNRabbit; 10-29-2010 at 06:34 AM.
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