If you are recharging a battery you will need to input more power than you could draw from the battery after charging, as the charging process is not 100% efficient. Most of this excess power will be lost as heat during charging.
No, not unless it has a voltage or current regulator or series resistance to limit the current (built in somewhere).
may be its around [5v;800ma]...
Diodes and rectifier
Boost charging involves a high current for short period of time to charge the battery. It is generally if the battery has been discharged heavily. Boost charge enables the quick charging of depleted batteries.
NO, a 12 volt battery cannot be charged with a 6 volt charger. To charge any battery, the charging voltage has to be, at least, slightly higher than higher than the voltage of the battery. Current flowing through the battery is what accomplishes the charging, and no current will flow at or below the voltage of the battery to be charged.
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.
There is not enough information. It depends on the type of battery: chemistry, cells, size.
That would also depend on battery chemistry.
Can You Charge...Yes. As a matter of fact, in order to charge a battery, the charging voltage HAS to be greater than the charged battery's voltage or no current will flow and charging cannot happen.Of course, the charging voltage cannot be excessive, or damage to the battery being charged will result.In your question, 4.6 volts is not excessive for a 4.2 volt battery.
The voltage in your house is AC. It is in the form of a sine wave that goes positive and negative 60 times a second. To charge a battery you need DC so you do an AC to DC conversion and then apply the DC to the battery charging circuit that applies the correct charging current to the battery and checks on the state of the charge.
No. A loose battery connector will cause problems drawing power from the battery to start the vehicle, and it may present a bit of a problem charging it (but that is not likely because the charging current is low compared to the starting current). If you have a loose connector and the battery goes dead, clean and tighten your battery terminals and start making some checks. The loose connector will not cause your battery to go dead.