OT: Car battery question

[jaybfresh]

Question for the more mechanically inclined than myself:

Anyone know if a dead car battery can still read 12v? I think my truck battery is drained, but it still reads 12.7v on a multimeter. I dont have a car big enough to jump it, so I wanted to double check before I bug my neighbor.

(And I dont believe the problem is the starter or the alternator. Went away for a week and came home to a dead truck. Wont turn over, no power to anything electronic for more than 10 seconds)

 

[superkat]

bug your neighbor. if you jump it, and the alternator is still good, it will recharge the battery. Also, check the connection to see if there is any corrosion around the posts...if there is, clean them off with baking soda and water and then smear them with vaseline. Gonna need to leave the vehicle running for awhile...if the charge doesn't hold...then you need a new battery and something else is going on...

 

[der_wille_zur_macht]

Are you measuring at the battery or elsewhere? Under load or no load? What happens when you try to start it? Any noises or signs of life at all?

 

[jaybfresh]

Hey Kat... already checked/cleaned the terminals. I had just thought that a battery reading 12.7v would indicate that the battery is charged, but the symptoms all seem to indicate the opposite.

 

[Willistein]

Take it to an auto parts store and they will test it for you. Yes, it can read OK with no load, but won't give current under load.

 

[jaybfresh]

Are you measuring at the battery or elsewhere? Under load or no load? What happens when you try to start it? Any noises or signs of life at all?

I measured on the battery terminals, then on the wires connecting to the battery. I havent traced the cables to the starter yet (which is probably my next thing to check). Cant measure anything under a load given that nothing will turn on

After sitting overnight, I get fans and a dome light on for about 20 sec. Not enough juice to power the radio. Sometimes I hear the solenoid clicks, but most of the time nothing.

 

[sg1838]

Question for the more mechanically inclined than myself:

Anyone know if a dead car battery can still read 12v? I think my truck battery is drained, but it still reads 12.7v on a multimeter. I dont have a car big enough to jump it, so I wanted to double check before I bug my neighbor.

(And I dont believe the problem is the starter or the alternator. Went away for a week and came home to a dead truck. Wont turn over, no power to anything electronic for more than 10 seconds)

A fully charged automotive 12V battery should read 13.2V. Sounds to me like you have a dead battery. I would put a charger on it (which can also be jumper cables from your neighbor's car - though it might take 30 minutes to charge like this), as this is certainly going to be the EASIEST thing to do. After that, you can take it out to an auto parts store and have them test it for internal shorts, or start screwing with starters / solenoids / wiring.

 

[jaybfresh]

Yea... I'll try to charge first. I dont need to bug the neighbor for his jumper cables, though. I need to bug him for his truck

Dont have anything else strong enough to charge my battery.

 

[alphaferret]

I can help ya at around 8;45pm

how did your tank do during your absence?

Oh and Kat-stop showing off-is there anything you don't have your hands into!!!???LOL!!

 

[jdoenumber2]

Question for the more mechanically inclined than myself:

Anyone know if a dead car battery can still read 12v? I think my truck battery is drained, but it still reads 12.7v on a multimeter. I dont have a car big enough to jump it, so I wanted to double check before I bug my neighbor.

(And I dont believe the problem is the starter or the alternator. Went away for a week and came home to a dead truck. Wont turn over, no power to anything electronic for more than 10 seconds)

Its not the volts that start the car its the Amps. As a battery gets older it can easily Read decent on voltage but sucks out on amps. You dont need a battery to run a car. Only to start it. If you get a jump i suggest you let it run for 10 mins then try to restart it. If it restarts with no hesitation chances are you left a light on somewhere. If it wont star you need new battery. In that case go with a interstate.

 

[aww_419]

Whens the last time you drove the vehicle? Any noises when you tried to start up? U should test the battery with the terminals off, but since you have them on turn your ignition to accessory. Then test again. it will more than likely drop below 9v. Thats a dead battery. no need to jump or anything else. It may be possible to slow bleed charge the battery back to full health but i would just buy a new one.

 

[jaybfresh]

Alpha... ygpm

jdoe... its only a year old battery so if something is wrong with it at least its under warranty.

 

[alphaferret]

we'll see ya at 8;45

 

[mr.maroonsalty]

are the terminals corroded?

 

[jaybfresh]

Terminals are a-ok. The battery is less than a year old. Alpha came over to try and jump it. Clicked a lot more, but still wouldnt turn over. But fireworks were coming from the ground end of the jumper cable on the frame of my truck. What does that indicate???

 

[backdraft79]

PMd you. Call me if you still need help in the morning.

 

[gregod]

the fireworks mean you are getting a connection. You may have to leave the car connected to the jumping car with the engine running higher than idle for a few minutes to give it enough boost to turn over.

 

[captain7359]

But fireworks were coming from the ground end of the jumper cable on the frame of my truck. What does that indicate???

Not grounded enough.


Hook it up to alphas ride, go inside, have a beer, come back out, start your ride, turn off alphas, go inside, have another beer, look at tank, have another beer, go outside, check to see if you still have gas, go back inside, have another beer, call alpha a cab, look at cab while waiting for tank, bid alpha a good night as you close the tank door, snag alphas battery, wait for him to ask for a jump in the morning.

 

[superkat]

Not grounded enough.


Hook it up to alphas ride, go inside, have a beer, come back out, start your ride, turn off alphas, go inside, have another beer, look at tank, have another beer, go outside, check to see if you still have gas, go back inside, have another beer, call alpha a cab, look at cab while waiting for tank, bid alpha a good night as you close the tank door, snag alphas battery, wait for him to ask for a jump in the morning.

perfect.

 

[sg1838]

Terminals are a-ok. The battery is less than a year old. Alpha came over to try and jump it. Clicked a lot more, but still wouldnt turn over. But fireworks were coming from the ground end of the jumper cable on the frame of my truck. What does that indicate???

You most likely didn't have a good enough ground. Is there a reason why you were grounding to the frame of your truck and not to the negative terminal of the battery?

1. Hook up the red cable on one end to the positive terminal of the dead battery.
2. Hook up the black cable from the same end to the negative terminal of the dead battery.

At this point, make sure the other ends of the jumper cables remain separated so that any little voltage left in the dead battery doesn't cause a short.

3. Hook up the last red cable to the positive terminal of the good battery.
4. Hook up the last black cable to the negative terminal of the good battery (you may see a small spark when doing so, this is normal).
5. Start the vehicle with the good battery. Let it run for at least 15 to 20 minutes connected like this to charge the dead battery. Increase the RPMs of the engine SLIGHTLY (i.e. don't floor it) to increase the rate of charging.

If once the battery is slightly charged you can identify what accessory was left in the on position to drain the battery, turn it off to increase the rate of charging.

Once the formerly dead battery has been charged for AT LEAST 15 to 20 minutes, try to start the vehicle. If the motor doesn't crank over fast (i.e. it seems to be struggling to turn the motor over), stop cranking immediately and let charge for another 15 to 20 minutes. If after a 2nd attempt the engine STILL will not crank over easily, then I would say you most likely have a bad battery and will need to be replaced.

As an alternative, if you can find a trickle charger, charge the battery overnight on the trickle charger and try to start it in the morning. If the engine will not turn over after charging the battery overnight with a trickle charger, then again you probably have a bad battery that needs to be replaced.