Strange battery problem

[bobcowan]

That doesn't make any sense. A battery doesn't work well in one car, and not at all in another car. It either holds a charge or it doesn't.

Take a look at what's different between the two cars. Something is wrong with the Cobra set up, that isn't wrong with the Mustang. If you don't figure out what the problem is, it's going to happen again with the new battery.

[L79v]

I would check battery cable connections...at both ends.

[Benzito]

Originally Posted by bobcowan

That doesn't make any sense. A battery doesn't work well in one car, and not at all in another car. It either holds a charge or it doesn't.

Take a look at what's different between the two cars. Something is wrong with the Cobra set up, that isn't wrong with the Mustang. If you don't figure out what the problem is, it's going to happen again with the new battery.

I agree it doesn't make any sense - that's why I posted about it.

The suspect Optima battery popped right up in the Mustang. The replacement popped right up in the Cobra. When I swapped back, I cleaned the posts to be safe (although I shouldn't have had to because of what I just described in the first two sentences - bad battery works and possible bad set-up works with good battery). Also, I've had the car since October and had zero signs of a battery issue with the suspect one . . . until now.

As for the battery cables, I think it was set up for an Optima - the cables are just the right length for the Optima and I had to contort them to fit a standard battery. Again, I never even opened the battery box until last Saturday and there are no signs of any wear or breakage.