Jump to content

Battery post arcing when hooked up


Buick35

Recommended Posts

On a 69 v.w. when I go to attach the neg. cable on the battery I get a spark or arc between the connection,just for one time,if I remove it right away and go to connect it it doesn't do it. Is something draining the battery or is that normal? I don't have an electric clock. The turn signals aren't working but they're in the off posistion.For now I've got the battery disconnected. I hate electrical problems! Thanks.

  • Like 1
Link to comment
Share on other sites

Radio with memory? One that was added later in life?

 

The small spark usually means charging of a capacitor. Once charged there is no spark, until later .

Edited by Frank DuVal (see edit history)
  • Like 1
Link to comment
Share on other sites

With everything shut off, no phone chargers plugged in the lighter, and don't turn the key on or anything like that...

 

1) Connect a old incandescent-type automotive test light between the bare battery post and the disconnected cable, so that the current is flowing through the light to get to the disconnected cable. After a second or two, does it glow brightly? If so, there is a problem. If it doesn't keep glowing at all it is probably fine.

 

Note: this test light needs to have a real light bulb inside, not an LED or something.

 

2) If it does keep glowing dimly, you can replace the test light with a digital multimeter set on milliamps, connected in series just like the light was so the current has to flow through it to get to the battery cable. For instance 500 milliamps (0.5 Amps) is too much. There were some Cadillacs that high but they go dead quick when sitting. 30-50 milliamps (0.03-0.05 Amps) would be more typical. An old VW would have been basically zero when new. Modern accessories like radios with memory will draw a little bit.

 

And yeah, I see you don't have a clock.

 

If you did I would ask you to disconnect it. A Borg type will mess with this test after it runs down, assuming the clock works properly. If it doesn't work properly, it is usually the whole problem.

 

test-light.jpg

 

 

Edited by Bloo (see edit history)
  • Like 4
Link to comment
Share on other sites

If you use a multimeter, and the amperage is high as stated above, try disconnecting your fuses one at a time to see which fuse causes the multimeter to go to 0. 
then check out what component that circuit feeds.

 

One thing that could be is the alternator. If you disconnect the alternator and the multimeter goes to 0 you need a new alternator.

  • Like 3
Link to comment
Share on other sites

Are we just assuming this initial spark represents a problem that needs to be found? I thinking the original poster is overthinking this situation, especially since a subsequent connection of the battery a few moments later doesn't generate a spark. As others have stated, it could be a clock winding, or a capacitor charging. I'd hook the battery up and not worry about this, UNLESS the battery subsequently becomes discharged. John

Edited by Jolly_John (see edit history)
Link to comment
Share on other sites

Awaiting radio answer. Something with memory?  ❄️

Edited by Frank DuVal (see edit history)
Link to comment
Share on other sites

1 hour ago, Jolly_John said:

Are we just assuming this initial spark represents a problem that needs to be found? I thinking the original poster is overthinking this situation, especially since a subsequent connection of the battery a few moments later doesn't generate a spark. As others have stated, it could be a clock winding, or a capacitor charging. I'd hook the battery up and not worry about this, UNLESS the battery subsequently becomes discharged. John

The battery I had in it was a $40 salvage yard one so maybe it went bad.I would charge it up and by morning it wouldn't turn the starter over. It has an ammeter in the dash that shows it's charging. I'll take the old battery to the parts store to have it checked out.Thanks

Link to comment
Share on other sites

6 hours ago, Bloo said:

With everything shut off, no phone chargers plugged in the lighter, and don't turn the key on or anything like that...

 

1) Connect a old incandescent-type automotive test light between the bare battery post and the disconnected cable, so that the current is flowing through the light to get to the disconnected cable. After a second or two, does it glow brightly? If so, there is a problem. If it doesn't keep glowing at all it is probably fine.

 

Note: this test light needs to have a real light bulb inside, not an LED or something.

 

2) If it does keep glowing dimly, you can replace the test light with a digital multimeter set on milliamps, connected in series just like the light was so the current has to flow through it to get to the battery cable. For instance 500 milliamps (0.5 Amps) is too much. There were some Cadillacs that high but they go dead quick when sitting. 30-50 milliamps (0.03-0.05 Amps) would be more typical. An old VW would have been basically zero when new. Modern accessories like radios with memory will draw a little bit.

 

And yeah, I see you don't have a clock.

 

If you did I would ask you to disconnect it. A Borg type will mess with this test after it runs down, assuming the clock works properly. If it doesn't work properly, it is usually the whole problem.

 

test-light.jpg

 

 

Thanks,I'll try that tomorrow.

  • Like 1
Link to comment
Share on other sites

Any spark when connecting a battery cable is a concern. That’s why we always disconnect the negative cable.  While uncommon a battery explosion is a real danger. Perhaps subsequent connections are not showing a visible spark, but a lesser transfer of current is still a possibility. Certainly it needs to be corrected.

  • Like 1
Link to comment
Share on other sites

Attach a test lite between the battery post and the cable.  disconnect bulbs and other accessories  one by one , even the alternator until the light goes off. There  must be no sparks  when attaching the battery cable except from the clock or dome lights. remove them too. It is a tedious process. There could also be a live wire grounding some where. It is not unusual for wires getting damaged , burned  during collision repair of body. I have seen that. I am not saying it is but these are possibilities.  

  • Like 1
Link to comment
Share on other sites

On 2/11/2024 at 9:16 AM, Rusty Heaps said:

Any spark when connecting a battery cable is a concern. That’s why we always disconnect the negative cable.  While uncommon a battery explosion is a real danger.

One disconnects the negative terminal on a negative ground car so the tools used to loosen the terminal will not make the BIG spark when they touch both the terminal and chassis. 

 

On positive ground cars one disconnects the positive terminal first, for the same reason.😉🛠️

 

 

On 2/11/2024 at 7:02 PM, Rusty_OToole said:

Shut off the dome light first.

 

While I agree with this, remove all known loads, the spark when first touching the terminal to the battery but no spark touching it again does not fit a dome light sparking characteristic. It fits a clock winding or capacitor charging spark characteristic.

 

Is this a Beetle? Then yes, the dome light is above the battery....   Not sure there is a switch to turn it off. Pretty basic car.

Link to comment
Share on other sites

26 minutes ago, bwbugay said:

isn't that battery under the rear seat ?   Then you have the door open  with the interior light on  ???

It's a Ghia so the battery is under the deck lid. The dome light isn't working but it might be shorting out.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...