dead battery (still)

[1980corvettegibson]

Im still having battery problems. I got a new battery at the end of Feb and now its dead. I took my car to the place that i got my speakers installed and they said they checked it and it wasnt the amp and they didnt find anything wrong. SO we got a DC amp meter that Rare81 had said to get. It shows that it checks DC curent, but we dont know what to set it on. We tryied it on 20 on the DC side and took the pos battery cable off, then i put the pos terminal on the cable and the negative on the battery. IT showed 18.76. There are 2 other wires, one comes from the stereo and the other is on something i dont know what is for the speakers. I check the one that comes from the stereo and it showed 18.76 also..so it was the same as the battery pos cable. That wire also has a 20 amp fuse in it. Then my dad checked the battery with the meter while i pulled fuses. I pulled all of them except a 25 and 70 that i couldnt reach and none of them caused it to stop. I pulled the dash out and checked the stereo wires...we pulled some of them apart and checked and it still showed 18.76 at the battery cable. SO i guess the battery cable is causeing the stereo wire to have fire in it..cause its probly hooked to it somewhere. SOOO my question is HOW is the battery cable getting fire through it like that? also i had the lights all out and key ignition off. My dad says that there is supose to be a little fire in it constatly..but if we checked it right, it showed nearly 20 Um amps i guess. We raised the hood and checked the altenator and it showed 18.76 at the place that my dad says is supose to always have fire. OH and our meter is off too i think, cause we checked the battery itself and it said that 18.76..so that made me feel like we wasnt checking it right. should i just take it to an ASE certified mechanic and have him fix it? or would that cost alot of money, cause he does charge $50 an hour labour. OH and also one last thing, im not sure which holes to put in the neg and pos on the meter also. Thanks for any help.

 

[mlt503]

Hey bud, just posted a question of my own and was following your mystery. I've got a little help for you. First, a typical car battery in relatively good shape should show 12 to 14 VDC (volts direct current). Secondly, it doesn't matter how you attach the multi-meter leads to the battery: on the positive side or the negative side of the battery.
Thirdly, if you attach them backwards, say the meter's pos lead to the battery's pos lead, you'll just end up reading -volts (minus volts). In that case you'll realize your mistake.
Fourth, since you now know the range of volts you can expect to see, it doesn't matter what setting "range" you adjust the meter to. If it's set to read less than 1 volt or 200, the meter is still "seeing" the correct voltage.
Now for some basic stuff I would start with. I understand this problem is fairly new?
Sounds like it's either got something to do with your new music rig or, just by chance something's shorted out involving the charging circuit?
Like the genteman above suggested, check the easiest things first: the fuses; then isolate each circuit betw the battery, alternator and starter and check for continuity.
Good luck and remember (this is VERY important): if if gets to you, walk away for a few minutes to calm down! You'll appreciate it later.
take it easy,
Mark

 

[1980corvettegibson]

Thanks alot for the relply. Since ya said you are having a problem too, heres my old post with some info http://www.corvetteactioncenter.com/forums/showthread.php?p=526717#post526717

course i thought the new battery fixed it, cause it started for a week, then like 2 weeks later i had to let it set cause my radator started leaking, then i got a new radator and put it on, and tried to start the car and it was dead agin...TOTALLY dead, not even enough for a buzz when i put in the key. My new music system is real big...its a 900 watt amp with 2 12" subs. We thought that when they hooked it up , they hooked a wire from the stereo into a wire that stays hot all the time. Which i dont know much bout wireing, but when i took the dash out, i checked a wire that was yellow and said "battery" and it had the same amount of fire in it as the battery cable. ILL try checking the negative cable instead tomorrow if its not raining. I had both my door panels off and my dash took out and my battery unhooked earlyer and knew i had to put it all back together, so i understand bout taking that break ya mentioned. I sure dont know what could be causing the battery cable to have fire in it while its unhooked from the battery, it seems very strange. And they said they checked their work at that speaker shop today...i had made an apointment last week for it. I dont have much time to fix this problem right now, cause im getting married the weekend after this one. I had planed on going to branson for our honeymoon, but i changed it cause the car problems to be around here where i live. I plan on driving my car, so i guess ill just have to take the cable loose when i park it at nights. The battery doesnt run down over night...it takes it 3 weeks. My old (over 6 years old) battery died cause of this and i had to get a new one. This problem started after we got those speakers and amp put in..and the first battery went dead bout 24 days after. We got that new battery finally and it went dead bout 24 days after we got it as well. I dont ever play the stereo without the car started neither. I really wished that i could find whats causing this short. Ive NEVER had battery or even wireing problems with my car and ive had it 6 years. SO if i check the neg side of the battery, should it say 000? and if it shows something, then that is how much my drain is and i can try to guess what it could be? I forgot to ask this, what is the charging circuit? is it that blue tube like thing comeing from my amp? cause i did check that and it was the only wire that didnt have any fire in it. Thanks agin for the help.

 

[wishuwerehere82]

If you still want to drive your Vette on your honeymoon and don't have time to fully investigate the amp draw problem.

Get one of those quick power disconnect knobs for your battery terminal, and disconnect it every time you are not driving it. That way it won't discharge while sitting there.

Or, put a switch on the power wires to your amp and reciever so it won't draw any power unless you turn it on.

 

[1980corvettegibson]

Thanks for all the replys. I did alot of tests friday and today. I took the Meter and pulled out fuses and put the meter wires to them, thats what my corvette book says to do to find a short circuit. I only tried bout 5 fuses, I ended up giving up, Because a few of them had power going through them, such as horn, and back lights when the head lights are on. Im confused, how can you find a short circuit if most of the fuses have power to them with the switch off? my fuse box lables are rubbed off also :ugh when i have time, ill probly just take it to a mechanic, alot of times my mechanic will check things for me and then let me take it home and fix it myself with no cost for checking...BUT im not sure if that would be the case with electrical short. I know that something is still draining it, cause we checked the power of the battery (18.76) Our meter is alittle off) and bout 3 hours it said 18.69. Does anyone know of a web site that shows a 1980 Corvette's fuse box? Ill check on here and see first. Thanks

 

[mmflytie]

dead battery in C-5

I thought the C-5's had to be left in "reverse " in order to make sure certain on board computers,etc. didn't draoin the battery. I know this was the case a t a dealership when I wanted to test-drive one.

 

[mmflytie]

My bad....sorry, I thought I had read where you had a trouble with a C-5

 

[wishuwerehere82]

Here's another post that explains the debug steps fairly well.

http://www.corvetteactioncenter.com/forums/showthread.php?t=49667&highlight=fuse+box

When you pull the fuses, all you need to monitor with the ammeter is between the positive battery terminal and the cable. You need to push in the door switch to keep the interior lights off while you do this too. The clock is the only other thing that should be running with the ignition off.

The most likely thing that could be causing this is that your power amp is plugged into an unswitched terminal on the fuse block and is drawing power all the time.

 

[geekinavette]

We tryied it on 20 on the DC side and took the pos battery cable off, then i put the pos terminal on the cable and the negative on the battery. IT showed 18.76.

I seriously doubt if you were drawing 20A of current...at 12V that would make for a pretty decent arc 'n spark when you connected the lead. Did the "20" by chance have a small "m" after it? 18.76mA (milli-amps), or 0.01876A, sounds a little more reasonable.

Bill

 

[I_R_DA_ONE]

some of the new amps. have a large capcitor in the line to surpress all engine noise and this maybe where you are getting the reading even when you disconnect the battery..... It sounds to me like the amp is not being turned off with the ignition switch
Mike

 

[1980corvettegibson]

well my readin on the amp meter is 18.76 between the positive cable and positive battery post. My amp does have a Blue round capaciter that goes to the battery that came in my wire kit, but when i tested it, it didnt have any power going through it. I had took my car to where i got the amp and speakers installed and they checked everything and said they couldnt find anything and that the amp wasnt comin on when the car was off. How would i disconnect my clock without disconnecting the gauges? OH i put a new steering wheel on it as well, and i remember when i did, the wheel moved up and down alittle bit, so i thought it might be something to do with the horn. My horn has gave me problems before, it would blow the amp everytime i would honk it. and we had that fuse out and i checked it across the fuse posts, cause that was what my book said to do..NOW is that with the battery connected..cause i would think it should be? Or is that wrong and i should be checking it across the battery cable when the fuse is out? ONE big question i have is should when i check the battery cable , should it show ANY power , or should it say 000? Yeah, my car is 80 and its also automatic, so it wouldnt be smart to leave it in reverse :L But thats good to know bout C 5s, i never knew that. Thanks for all the help. Ill find it someday if i have to take it to a Corvette specialist

 

[wishuwerehere82]

Can you tell me what model and manufacturer your meter is?
I am having trouble understanding what your readings are indicating. If I knew what meter you are using, I could tell you more about how the readings are being used.

 

[Mr. Chuck]

Finding electrical short can be simplified by doing trouble shooting in a slow, orderly way as follows:
Key is to record the results as circuits are eliminated as you remove it's respective fuse. The key is to not get in a hurry and get confused as which circuits have been tested & results obtained. Some basic questions as to the Amp meter you are using? How many current ranges does it have? Are they selected by dial switch or do you plug in the test leads at different jacks? Are you able to hard connect the Amp Meter between the battery post and the battery cable, instead of having to hold the leads? Knowing this information makes giving trouble shooting hints easier.
The amp meter if connected in the positive side of the battery would be connected with the red test lead end to the (+) battery post, while the amp meter black lead is connected to the loose end of the (+) battery cable; You should start with the meter set to the highest current scale (will reduce the chance of damaging the meter circuits). Record all current reading with ignition switch off and door lights off. Normal reading should only be for the clock, which should be a fraction of one amp. If current reads more than this start by pulling fuses to isolate the short draining the battery and record current. Proceed with the following steps:
1. Disconnect the power from the new radio / speakers system. record results; if no change or very little, go to next step;
2. Start with fuse panel in a given order / position and work your way around. Pull one fuse at a time and record results;
3. repeat this procedure for each fuse and / or circuit breaker.
4. Replace fuses immediately that showed no change in the current drain, this helps to reduce the chance on putting the fuse back in the wrong location, since most fuse panel will have some unused positions of options not in your car.
Hint: Trouble shooting is quicker if you have a helper to read and record amp meter readings. If working alone, use long meter leads so you can read meter from inside the car to limit the time too get up to read the meter. Also insure that battery cable doesn't short out on any metal part of the car frame or other electrical connects, which may cause damage to electrical system / components or cause a fire. Also noted / listen for any sounds of motors running or the like with the ignition still off. Big note; insure that you only pull fuses with the ignition switch is "OFF" Circuit damage may result if you pull fuse with the power connected to a given circuit. Also if you have the hood open and you have a engine compartment liight, you take the bulb out.
Good luck: You can reach me direct at e-mail cddmhr@peoplepc.com

 

[1980corvettegibson]

K, my meter is electro-tec from wal mart. it was $17 and its yellow. with dial switch. It has the leads that you hold. It has 3 holes to put them into. I dont have it with me at the moment, or i could tell ya more. from what you said, i have been checkin the battery wrong, because i was putting the red positive to the cable and the black neg to the battery...so ill try switching it around. My dad helps me read the meter, but he doesnt know much about how to use it. He is used to real expensive ones (he used to work at a feed mill) that all you have to do is put the clips on a wire and it will show if there is a short, but we dont got one of those.

 

[Mr. Chuck]

Wal-Mart web site (http://www.walmart.com/catalog/product.gsp?product_id=656131) shows an electrical trouble shooting book. Titled Automotive Electrical Systems: Troubleshooting and Repair Basics
Author: Martin, Vaughn D. that looks like a good starting point for folks with a novice electrical background. I often forget that not everyone is big on technical subject matters and how much electrical knowledge I have obtained over the last 48 years between the Navy and computer manufacturing work experience. One other course of action may make life easier is if you have one of the following or an auto parts stores that performs free auto electrical system tests. Here in Southern Cal we have the Auto Zone or Kragen that will test auto electrical system to determine correct alternator output (voltage & current) to it's rated values under full load. Low output will fail to keep your battery fully charged). They also perform limited test of the battery. I also believe that they can measure the electrical load (amps) the alternator is higher than expected (results of a short or if your new amp (radio / speakers) is over loading it). An electrical over load may pull down the alternator output voltage to a point that the battery is not being fully recharged in the reason period of drive time. At one time there was a belief that it took 40 minites drive time above 40 mph to recharge the battery after one normal start. That time has decreased some what with the switch to alternator with greater current / load capacities.

 

[1980corvettegibson]

I seen that book when i was tryin to find you guys a pic of my meter. I thought of that, bout the radio pulling the charge down while i drive, BUT the thing is that my battery goes dead while setting still for a week or 2. Ill probly just give up and get an easy disconnect switch. Right now i have my meter and ill post everything that it has on it. starting from top clockwise:

Off, {AC V~ 600 200} {DC V- 600 200 20 2} {DC mA- 200 20/10A 2} {NPN/LED hFE PNP} Ohms 200/sound 2K 20K 200K 2M 20M
Now ill post the 3 holes it has to put the post in from left to righ

VohmmA Max DC600V AC600V
Com Max 10A Max 500V DC/AC
10A

Im not sure if ALL Corvettes have the battery behind the seat, but i figure all stingrays do..so since its behind the seat i might just get a $12 easy disconnect switch one day. but i would rather not have to reach behind the seat everytime i go somewhere. even though im having to right now OH, Mr. Chuck, i tried to e-mail you to get that picture, but it came back and said it couldnt send. So im not sure whats wrong there but i would like to have that picture. My e-mail is danny_and_mandy@yahoo.com Thanks

 

[wishuwerehere82]

Thanks for the rundown on the meter setting.

The maximum current your meter can read is 10 Amps if the black lead is plugged into the COM (or Common) hole, and your red lead is plugged into the 10A hole. The rotary switch need to be set for DC AMPS 10 A. If it set up this way and your are reading 18-20 then it is reading Milliamps which are thousandths of an Amp.

If you put your meter between the positive lead and the positive terminal on the battery, with the red lead on the battery, the meter will tell you how much current the system is drawing. As you turn things on, the number will go up accordingly. Your clock is probably drawing the 18 Milliamps. If you turn on your headlights for example, it will max out the meter at 9.1 Amps since they are 110 Watts for both lamps. Volts X Amps = Watts.

If you pull one fuse at a time and watch the meter to see when the current drops to 0 then you have found the circuit that is drawing the current that is draining your battery.

The battery switch is probably a good idea to get if you run out of time to figure this out.

 

[1980corvettegibson]

Thank u so much. Thats what i was needing to know, is how to set up the meter. Its raining right now and we dont have a garage, but ill test it like that tomorrow and see what i can find out. If it is the clock, how do i unhook it without unhookin my gauges?

 

[wishuwerehere82]

You can just ignore the 18-20 Ma. that your clock is drawing. You're looking for a bigger number than that. Something like 1/2-1 amp. I'm not saying that your clock isn't causing the drain, just probably not. I think you are on the right track with the amplifier/stereo, but check everything just to make sure.

 

[1980corvettegibson]

I fount something. I set it to 10A and tested it and it read .99 Then i pulled the fuse to the horn and it went to 000. We looked at the horn and there is another wire going somewhere else. My dad reached under there and felt something that was round...it might be a car alarm or something. We unhooked the horn and put the fuse in and it read 2.88, then we unhooked that other thing and it still read 2.88. We pulled the fuse back out expecting to see the 000 agin, but it read 1.90. SO im not sure why it has went back up with no fuse unless i hadnt gotten it checked very well the first time. The horn must have been causing a big drain though. I pulled other fuses and having fount what else is causing the rest , but my dad had the positive lead placed in the battery so that he could just put the negitive wire to the cable, I Guess the neg wire got grounded or something :ugh Because the wires started smoking and melted together. SO thats the end of our search for today. BUT i think it is the horn now or something else thats on the horn circuit. but its still not all the way down to 000 yet. I forgot all about sayin that my car has a battery shut off on the ground wire, I have never used it cause i wasnt sure if it worked or not, so i can use that if i want to shut the power off from it, but i still dont want to have to reach back there lol i guess im lazy :L