alternator or battery

[wowiesy]

on a 2000 ranger 4x4.. today lang lumabas tong problem na to ...

after driving around 60kms from manila to pampanga and back to bulacan, i left my pickup at the parking space in our plant around 2pm... around 8pm.. nung paalis na ako ng planta.. started the engine.. okay naman..

observed ko lang na kapag naka idle.. or kahit na naka gear na ako on 1st... and medyo mababa pa ang rpm.. parang nag flu fluctuate yung mga ilaw ng displays sa dashboard (tacho, speed, etc)... pati yung battery indicator and oil indicator parang gustomg umilaw.... it was like this for about 5kms... pinatay ko na aircon at radio at baka kasi battery or alternator problem.. pinagdasal ko rin na sana hindi tumirik at late na ako at hinihintay na ako ng gf ko...

anyway.. nung umabot na ako ng expressway at bumilis bilis na ang takbo ko... nawala na...

ano kaya problem na to? kaka refill ko lang ng tubig sa baterya about 3 weeks ago...

[OTEP]

The battery is usually only used to start the vehicle.

Either you have an alternator problem (maybe as simple as a loose belt) or an idling problem causing your engine (and the alternator attached to it) to bog down at low rpm.