Automotive batteries are not known for their "deep cycle" capabilities. If possible, don't allow them to EVER discharge completely.
As long as the battery is functional you can continue to jump it. However, know that every time you run a car battery down you shorten its life. A battery that is designed to be run completely down and then recharged is called a deep cycle battery. Automobile batteries are not deep cycle batteries. Discharging them completely causes damage to the battery itself.
Over and over as long as the donor car is running. How many times is hard to tell.
Do you wish to jump a car with a deep-cycle battery, or do you wish to charge another battery using the deep-cycle battery?
Yes
Yes
When you say boat battery if you are referring to a Deep Cycle battery as used to power a trolling motor then no, it is not suitable for use in a car. However, if you are referring to a battery in a boat used to start the engine and it is not a Deep Cycle battery it will work just fine in a car as long as it fits the battery holder, can be strapped down, and the battery posts are orientated correctly.
You don't. This would put a strain on the alternator and may burn a diode out. Charge it with a deep cycle battery charger.
Deep cycle means that the battery gets almost totally drained before recharging occurs. You'd find this on batteries connected to solar panels for instance that are used at night. These batteries differ from a motorcar battery as draining a car battery completely, damages the battery. Deep cycle batteries are designed to deal with this and are usually more expensive than car batteries.
There are several battery car systems that can be considered popular because many people used them. These are the flooded cell batteries, sealed batteries, deep cycle batteries and lithium-ion batteries.
yes as long as it is a 12volt battery - i have done it many times.
Yes and no. If you use a jumping unit, most have a setting that should match your cycle's battery voltage and limit current. You can jump one cycle's battery with another cycle's battery provided they are the same voltage and a rechargable-friendly (for example lead-acid) chemistry.
Yes, you can definitely buy a car battery online. There are many dealership websites that you can visit online to purchase a car battery and there are many auto stores that you can go online to purchase a car battery.