Help: Battery dies in 5 secs!

Battery internally shorted? Happens with age. Tap the battery case lightly with a hammer and try again. has helped me before in a pinch, until I got a new battery. Also test with a known good battery too.

Jan

Hi,

I've been fixing the lights of my '72 SB and today I found a new problem I didn't have yesterday. When I turn the contact on I can see the needle of the voltmeter going down in 5 seconds from 12 to nothing. I try to locate the problem. Removing all the fuses doesn't prevent it to happen, so I unplug the battery wire from the fuse box and that's it. I follow the wire and it seems to be a problem in the contact-coil circuit, but I check it and I see no rusty/dirty connection, and the voltages at the coil terminals are fine, around 11v, right? I don't know what else to do, any help to locate this short circuit?

Ant

I had a battery like that only last week. It fell out of the crummy mounts I made and shorted positive and negative terminals on a crossbar and _fried_ itself. (The crossbar got _realy_ hot, too.) Afterwards it appeared take a trickle charge, but the very moment it was hit with a load, it went to zero volts.

I don't think it is a problem in the contacts, I cleaned them. In fact I am following all the possibly involved lines and cleaning all the contacts. Besides, there are actually two voltmeters, the dash one, and an extra one I connect to the battery, both give the same reading. Maybe is something related with the quite warm coil I had a couple of days ago?

Ant

J Stafford wrote:

Sorry for my english inaccuracy. I mean "When I turn the key contact on" , but without starting the engine. And I measure the voltage at the battery. So the voltage I measure is with a voltmeter I plugged to the batery itself. if then I swicht it off the battery goes back to 12v.

Ant

Ant wrote: