A laptop battery can be charged while using it, but it would not be likely to become overcharged when the laptop is in use, unless the laptop goes into a sleep or dormant state.
No. When a laptop is plugged in, it immediately switches to AC power and begins charging the battery. The battery cannot become "overcharged" because special circuitry in the battery is designed to prevent this.
It shouldn't - the laptop should be fitted with circuitry to stop charging the battery once it's full. That way, the battery cannot be overcharged. If you're always using the laptop at home (or near a mains socket) - you can simply remove the battery, and just run it off the mains.
No, my laptop and battery never happened like this. You need check your bios and your battery model. I linked a site below with some laptop battery using tips.
get a new laptop
Yes, if the charger does not automatically shut down when the battery is fully charged.
Their battery do not lasts long
Using a Dell 6400 battery on a different brand of laptop runs the risk of send too much or too little power to the system. This may cause the laptop to crash or overheat unless the battery fits the specifications of the laptop.
The shopkeeper overcharged the person for the book. This is a sentence using the word overcharged.
Sorry, but that is not likely to work. Both the voltage and amperage provided by a charger for a laptop battery will not be correct for a car battery. It is likely that you will damage the charger.
we can use a dc voltage directly from a dc source with parameters equal that of the battery
yes
As long as the laptop is plugged in already, and 'charging' the battery, yes. I often remove the battery and start charging another one while in use.