Hindi ba dapat kaya ng stock alternator to support all of the electrical needs of the car and the charging of the battery? If not, then after a night's drive, eventually mauubos ang charge ng battery.
I am no mechanic, just thinking aloud :D. in this casse of the TS. kung namamatayan siya lagi ng makina it may be possible na alternator ang problem. It cannot give the needed current to support all electricals and charge the battery.
If I am not mistaken, a brand new battery is not fully charged when delivered due to the shelf life of the battery. basically habang nasa shelf siya (hindi pa nabebenta) dahan dahan nauubos ang charge.
If daytime driving, wala ang problem. malamang alternator nga.