Car does not turn off

How is the combination meter (speed, odo, fuel, mpg, PRNDB) behaving?

 

Can you confirm that what you mean here is you have disconnected the negative cable from a fully charged battery and left it disconnected for the whole night, then when you checked the voltage of the new battery with a volt meter the next day, it was completely drained–i.e., measured 0 volts. If this is not what you meant, can you state exactly what happened?

 

It could also have meant "around 10 volts or less", a common threshold for "completely drained" for a 12-volt lead-acid battery.

 

Understood, but that is not what I was going for. I was intrigued by the battery draining when it was not connected to the car—if that's what happened. Hence the quest for clarification.

 

Once you get a fully charged 12v and have checked the 12v connections to be sure they aren't loose we can help with a diagnosis. But I'm fairly certain that once that's addressed you won't have any more problems.

 

A battery cannot "drain" if there is not a complete current loop for the electrons to follow. If the negative lead is truly off the battery and that battery's open circuit voltage actually drops then the battery is toast, severely damaged (or worn) internally. The normal 24h open circuit self discharge on a working AGM battery is a tiny fraction of a volt. That's how they can sell them "charged". They are fully charged (essentially, actually loading them with fresh electrolyte is the same thing) at the factory, and then they will hold most of that charge for a year and half in storage, shipping, and sitting on the shelf at the store.

 

While true, you need to fully charge a battery after you buy it prior to installing it. There's way too many folks out there who think you can install a 12v right off the shelf without making sure its charged first and that annoys me every time I hear it.

 

Agreed. While the battery is still usable at a year it may only be charged to 12.2 volts, or something like that. Automotive charging systems, at least these days, are much better at maintaining voltage than at recharging a battery. So it is better to charge it up with a dedicated charging device before installation. Unfortunately a lot of people don't own one of these, and if they have the work done at a shop they aren't going to take the time, so the battery usually goes in at the lower voltage and the car will take a while to get the battery up to a full charge.

One other reason to charge it up first. Most modern chargers will detect if a battery is really screwed up and turn on a red LED or something similar. If that happens, take the battery right back to where it was purchased and try again. The same bad battery installed in a car might damage the charging system. Having a car fail this way is probably a very rare event, but with tens of millions of batteries being installed each year, it must happen.