My battery died! Did that injure it ?

NO. But there are a few exceptions to everything.

 

Driving our car only every second or third day, I just leave ours on a smart charger all the time now. No worries: sits in "float" mode.

 

Probably but why would you WANT to do it that way ??
Much better if you replace it when you first start seeing evidence that it is going bad.
If you wait for total failure, Mr. Murphy says that will happen at the WORST possible time.

 

Just like engine oil: just replace it at an interval that you're ok with.

 

Just occurred to me: the title of this thread is pretty funny.

 

well this depend where you are driving .... even in the USA you may NOT find a fitting 12V battery the same day ... yes you can use any battery but the way you are asking doubt you could

 

That begs the question then... what happens when you replace the dead battery and re-establish 12v? What is the difference between re-establishing 12v by replacing the battery and re-establishing 12v by connecting jumper cables?

 

If you replace the battery, you leave it connected. Jumper cables are normally disconnected before driving the car. If, as originally stated, the battery will not take a charge, the relay would open when the cables are disconnected and the 12V disappears.

That's my theory, anyway. I do not plan on testing it, though.

 

But, once the car is in Ready mode the 12v is being supplied by a DC/DC inverter coming from power supplied the traction battery. Once the car is in Ready mode, 12v does not get disconnected when the jumper cables are. The 12v gets supplied by the normal battery charging circuit activated when in Ready mode.

 

Untested theories, Confederate currency, BRIC shares (a BC thing):

When we test-drove our car, it'd been sitting for over a year, 12 volt dead as a doornail. They jumpstarted it and left it running. To "warm it up" for us, they explained... The ruse fell apart later, when we were in discussion with the salesman: needed to restart the car, not happening.

 

But, the question is - the car remained "running" after they disconnected the jumper cables, correct? Then when they tried to restart the car on battery only, the battery still did not have enough charge to do so?

 

Yes. The car ran fine during our test drive. And the car was completely inoperative when they tried to restart it.

 

Thanks!

 

Others have "tested" it for you.....and your conclusion is WRONG.
Several people have told you that already; how many more will it take ???

 

OK, Mendel has tested it. I must have missed any others.
But I still think it is not a good idea to run the 12V battery until it is dead. That is my opinion, though.

 

That is a different statement than what you said before.
And THAT is not just an opinion but a fact, supported by the battery makers, car makers and a LOT of personal experience.

 

Sam, regardless of the rights-and-wrongs, maybe take a deep breath, realize this isn't life-and-death stuff, lol.