Dead battery

speedracer · February 26, 2006, 11:11:59 AM

OK guys, my battery is went down real fast. Drove the ride to the mall and upon return the battery was to weak to turn it over fast enough. Got a jump made it home put on the charger for 3 or 4 hours and she's charged back up, but when I start it the voltage meter is reading zero! Like no charging at all. This all happen really fast, the car always started and now this, the alternator is new 1 wire for jegs but the battery is interstate probably 2 years old. Is there a test I can do to check out any shorts or dead battery/alternator? Thanks, Johnny

moparrodder · February 26, 2006, 11:26:09 AM

Johnny, Have your battery charged and start the motor then take the ground cable off the battery and if it dies the alternator is not charging and if it stays running it's good. To check battery get a load tester and that will tell you if the battery is good or not, also check your amp gauge for shorts I had one that went bad on a chevy pickup and would drain the battery fast, changed it and no more problems. Hope this helps. Bill

speedracer · February 26, 2006, 11:33:20 AM

Quote from: "moparrodder"Johnny, Have your battery charged and start the motor then take the ground cable off the battery and if it dies the alternator is not charging and if it stays running it's good. To check battery get a load tester and that will tell you if the battery is good or not, also check your amp gauge for shorts I had one that went bad on a chevy pickup and would drain the battery fast, changed it and no more problems. Hope this helps. Bill

Thanks Bill I'll do that!

tomslik · February 26, 2006, 11:58:04 AM

Quote from: "moparrodder"Johnny, Have your battery charged and start the motor then take the ground cable off the battery and if it dies the alternator is not charging and if it stays running it's good. problems. Bill

do NOT do this if you have a computer!!!!
you think you gots problems now....

Crosley.In.AZ · February 26, 2006, 12:21:40 PM

Quote from: "tomslik"
Quote from: "moparrodder"Johnny, Have your battery charged and start the motor then take the ground cable off the battery and if it dies the alternator is not charging and if it stays running it's good. problems. Bill

do NOT do this if you have a computer!!!!
you think you gots problems now....

hee hee ....... oh boy !

donsrods · February 26, 2006, 12:53:30 PM

Here are a few thoughts. There are only so many components that will affect starting/charging so consider these:

1) You say your battery is 2 years old. I live in Florida, like you, and 2 years is about all we can expect with the heat and all. Have it load tested.

2) Are all of your battery connections tight and shiny? Also, are the connections to the starter and engine block ground clean and shiny?

3) A one wire alternator simply has that one lead going from the alternator to the battery positive. Is is in good condition and also clean and shiny.

4) Diodes go in alternators, allowing the current to backflow and drain a battery.

5) Head down to Autozone or Discount auto. They will put it on a tester free, and tell you what the starter draw is, the alternator output, etc. Why wrestle with it in the driveway when you can get the answer in 5 minutes, and for free?

The reason I stress clean and shiny so much is I work in a marina, and every day of the week some boat comes in with starting/charging problems. 80% of the time, we clean some corrosion off of the cables and it goes away. It is a big problem, especially here in Florida with the rain, humidity, etc.

Good luck.

Don

moparrodder · February 26, 2006, 12:57:06 PM

If the info I gave is incorrect then it's my fault but we have done this on several pickups at work and even our Mountianeer all were 97 or newer and have not had a problem with doing it , and all were Ford products , must have stupid luck looking over our shoulders. I guess I thought that I could answer a question once where I and my boss had had done this without a problem, guess I better stick to asking questions instead of answering them. BILL

donsrods · February 26, 2006, 01:24:32 PM

Bill: Don't ever stop trying to answer some question because you think you might be wrong. There have been a zillion times where I gave my opinion, only to be corrected, and it hasn't stopped me from shooting my big mouth off. When I come on a forum like this, I realize there are guys who actually turn wrenches for a living, or who have been doing stuff that is well beyond anything I could do or build. But I still like to answer a question to the best of my ability, now and then, even though sometimes someone comes up with a better solution than mine.

The nice thing about these forums is that there is a system of "checks and balances" where I may say something that someone else feels is incorrect or could be done another way. There was no harm done, and I learned something too about disconnecting the cables. Hell, I have even removed a battery from a running car and put one back in it. I guess I lucked out too.

The fact that you tried to help is the important thing. That is all any of us do here, we try to help.

Now I think I will head over to my shop and actually try working on my car rather than just sitting here, eating my cereal, and reading about cars.

Once again, keep posting............it's what makes these forums work.

Don

enjenjo · February 26, 2006, 02:07:20 PM

The best way to check this is with a hand held Voltmeter. You can get them for $10 or so, actually a multimeter, at most parts stores, Radio shack, Home Depot, or Harbor Freight. they come in handy many times.

Check the voltage across the battery, nothing on. You should see 11.6 volts or better. If it's lower, charge the battery. If it won't come up to 11.6 volts, the battery is bad.

With the voltmeter still connected across the battery, start the engine. You should see 13.8 volts or better. With a one wire alternator, you may have to rev the engine once to get it to start charging. If it's lower than 13.8, but higher than 12.2, the alternator output is low, and the internal regulator is bad, or there are other problems with the alternator. If the charge rate is ok, but the car still ends up with a dead battery after a short period of time, check the amperage draw with every thing off, and the ground disconnected from the battery. Connect an Ammeter between the barrey ground cable, and the ground post of the battery. you should see ledd than .02 amp draw. If it's more than that, start by disconnesting the alternator, and see if that drops the amperage draw. If it does, the diodes are bad. If not, start pulling fuses until you find the circuit with the draw. when you find the correct circuit, you can trace down the short in that circuit.

If the voltmeter on your dash shows no voltage, youi have wiring problems, it should show voltage, even if it's low.

The reason for not disconnecting the battery with the engine running. The voltage regulator works by sampling the battery voltage, and setting the chage rate accordingly. When you disconnect it, it drop the sensing voltage, causing the regulator to raise the charge rate. Depending on the circumstances, it can cause the charge rate to go into the 20+ volt range, and voltage spikes kill splid state electronics, including computers, ignition modules, and strangely enough voltage regulators.

speedracer · February 26, 2006, 02:57:16 PM

Well I cleaned the posts and wiring and that didn't help, meter still show discharging (not totally at the end of the red but in it) I pulled the ground wire off the battery while engine running and engine died emediatly. (I pulled all the computer crap off the car along time ago). I do have a mulitimeter, don't know why i havent thought of using it, but will here very shortly and let you know, ok. thank, johnny

Nick32Vic · February 26, 2006, 10:47:06 PM

Just out of curiosity what kind of vehicle/engine is this on?

speedracer · February 27, 2006, 01:00:24 AM

Its a 1985 El Camino SS/355/700R4/4:10 gears.

Mr Cool · February 27, 2006, 08:29:52 AM

If you dont have access to a load tester you can do it yourself very easily.
Remove ALL of the fill caps from the battery, remove the ignition lead and have someone crank the engine.
This will put a large load on the battery.
Look into each battery cell, and if you see one of them bubbling away while you have a load on it (in this case the starter motor), the battery is stuffed, get a new one. You should also monitor the battery voltage with the multimeter, if it drops below about 9 or 10 volts its likely also buggered, look harder for the bubbles and I'll bet they are there.
If you want to check high charging/discharging currents, get the multimeter and select the mVolt range (No, not a typo).
Put one meter lead onto the battery -ve post, the other onto the engine block.
This will give you positive and negative readings, using the battery lead as a current shunt. It works simply because the current passing through the cable is directly proportional to the voltage drop, which is what you are reading. You should have a negative reading without the engine running, and say the headlights on. If you dont get this, swap the leads over so you do.
Now try it with the engine running and you should have positive readings. this shows that the alternator is working correctly.
You could actually work out the exact current passing through the cable, but you would need to know the exact resistance of that length of cable, however small it is which is not so easy to measure without the right equipment.
These are only a basic tests that anyone could do at home to prove whether their battery and /or charging system are working correctly or not.

Hope this helps someone.

Mikej · February 27, 2006, 11:41:08 AM

You should have 2.1 volts per cell approx. A fully charged battery should have 12.6 volts approx. If you have removable caps, you can put your volt meter probes into the acid and check each cell. So if after you charged it if you only have 10.5 volts, you have a bad cell. It can go bad all at once.

Crosley.In.AZ · February 27, 2006, 10:11:04 PM

I am thinking he will find a problem with the alt as enjenjo was pointing out.

Could be a bad connection too.

I've had a few of each.