battery

If your positive the alternator is good, then you could have some kind of parasite drain keeping the battery active constantly draining it.check inside light switch to make sure it isnt on and make sure all doors and hatch are shut to keep interior lights off.

It sounds like a parasitic draw on the battery (something staying live with the key off). I suppose one way to test this is charge the battery leave it disconnected over night and reconnect it. If the car starts then the battery is good because it held a charge over night, if you reconnect the battery that was charged the previous day and the lights won't work and the engine won't crank over then it is likely the battery is bad. To isolate a battery draw the key must be out of the ignition door closed and then fuses are removed one at a time watching amp draw on the battery. When you remove a fuse and the battery draw goes away you have found the circuit causing the draw and all the individual circuits protected by that fuse need to be investigated to see which one of those is responsible for the draw that is killing the battery over night.