2 dead car batteries, not charging

[EdwardC]

Few questions first:

What is the present voltage of the batteries?

Does your charger indicate any current output when you connect it up?

An easy test to see if the charger is doing anything is to measure the voltage of the battery, then connect the charger and measure the voltage to see if it's higher with the charger connected.

One way to test the battery would require first charge up the battery (if it'll take a charge), then get it load tested to see if it can put out the current you need. If you can't get it to stay above 12V, it's probably toast.

No sparks could indicate that the charger isn't working.

Depending on the state of the battery, I think that trying to jump start the car could be dangerous, personally, I would swap the battery from a good car or use a jump box.

 

[Donald]

Originally Posted By: cutchemist42
So I have two batteries that seem to be dead at the same time, and a charger that wont charge them.

What troubleshooting proves its the batters or the charger? There is no sparking like I usually expect there to be.


The newer chargers will not spark. They verify proper connections to the battery before they start the charge.

But you can measure the voltage across the battery with the charger connected and running. It needs to be higher than with the charger not connected.

 

[901Memphis]

I do not believe there are any tests to perform on dead batteries. You will want to have them fully charged to perform any meaningful tests.

If you can jump start the car, let it run for maybe 5 minutes, then pull the battery and fully charge it on your automatic charger, you can bring the battery by itself to a good auto parts store and they can test it much more accurately. Advance has a good tester here.

 

[cutchemist42]

Originally Posted By: EdwardC
Few questions first:

What is the present voltage of the batteries?

Does your charger indicate any current output when you connect it up?

An easy test to see if the charger is doing anything is to measure the voltage of the battery, then connect the charger and measure the voltage to see if it's higher with the charger connected.

One way to test the battery would require first charge up the battery (if it'll take a charge), then get it load tested to see if it can put out the current you need. If you can't get it to stay above 12V, it's probably toast.

No sparks could indicate that the charger isn't working.

Depending on the state of the battery, I think that trying to jump start the car could be dangerous, personally, I would swap the battery from a good car or use a jump box.


I do not know the present voltage of the battery, how can I find that out?

What is meant by current output when I connect it? How do I see that?

 

[EdwardC]

Take a voltmeter and set it to read DC Volts in the 20V range, then touch the red lead to the positive and the black lead to the negative. Even a cheapie digital volt meter (DVM) would work. I keep this one in the garage just for this kind of thing: http://www.harborfreight.com/7-function-multimeter-98025.html

As for the charger, the one you linked above ( https://www.gcsurplus.ca/ic-ci/images/FS330847-231847.jpg ) has the "Amps" indicator. Connect it to the battery and keep the switches on Normal, Charge, 12A, then see if the indicator swings over to the right. If it is, then it should be working.

To be honest, if you just need to move them a few feet, I would try jump it, if it starts, move it, or better yet, drive it around a few minutes. Then when you park it, take the battery out and throw it on the charger to get it back to 100%. If you can avoid it, don't drive too long since the car's electrical system isn't made to charge a completely dead battery.