Multiple possibilities.
Most probably if it does it every time you don't start it for a few days, you have some parasite consumer (a light that does not switch off for example).
Other possibility is that your alternator does not charge enough or the batery, even new, it's faulty.
If just clicking and not starting, most likely a dead battery.
You need to charge the battery with a battery charger.
If the donor vehicle is running and has a properly functioning alternator, no.
no the car wont start because the battery is dead, it was discharged by running it and not being recarged by the alt
No, You do not need a key fob to start a car. When starting a car, you put the key in the ignition and turn. Power comes from car battery, not from the key fob battery!
battery dead.
That could be the alternator or the battery. Try jump starting your car with another car's battery. If it still does not start, it is probably the alternator. If it starts, your battery is dead.
You should never drive a car around for long after jump starting a dead battery. This puts an enormous strain on the alternator. Alternators are designed to keep a good battery charged, not to charge a dead battery. You can easily burn out a diode in the alternator. Jump start the engine and drive it somewhere and connect a battery charger to the battery and charge it fully.
If your battery is good and you know your car is draining it then yes, disconnecting your battery from your car will keep your battery charged for much longer than 3 days. Your battery should stay charged way longer than 3 days in normal conditions being hooked up to your car. You should get it checked out and figure out what is draining your battery so fast.
A battery jump starter works by taking the charge from another battery, such as in another car, and passing it to the dead battery. When the charge is sufficient in starting the dead battery, it should then start charging itself as the engine runs.
I would expect that the battery is dead; however, instead of jump starting the car, it is far easier on your car's charging system to place a battery charger on it for about 6 hours then start the car. Otherwise, the alternator tries to charge the dead battery at a wide open rate and it can damage your alternator. Mark
An alternator is designed to keep a fully charged battery at peak level. It is not designed to charge a dead battery. Installing a new alternator on a car with a dead battery can in some cases ruin the new alternator. Fully charge the dead battery before starting the engine.