Gen IV hatch @ 175k. Out of the blue, the Battery light came on. Then off. On again. Flashing, blinking - you know the drill. Revs would usually kill it, indicating that it was probably an internal alternator problem. Threads mentioned wiring connections, belt tension and the alternator brushes. Wiring and belt were good. From experience with Japanese motorcycles, I knew that alternator brushes are an expendable item and need occasional replacement. So, I pulled the alt using great tips found in the threads here. Popped off the brush holder. Manual says 1/4" (6mm) of brush protrusion. I had 3-4mm. One brush was polished (as it should be) where it contacted the commutator, but the other looked like it had been arcing, and it probably had been. No time to wait for a web purchase, so I found a dealer with replacement brushes in stock (31105-PZ1-003), cleaned the commutator with no-residue solvent and installed the new brushes. Bam! 14.2 volts at idle and no more light. Figure on possibly needing the brushes anywhere over 100k, certainly expect it at 150k+. OEM can be found for $20+/- & shipping on the web. I can give step-by-step if needed.