Ford Focus Electrical Charging

TBOYD

MEMBER
FORD FOCUS

This question is regarding a 2002 Ford Focus Wagon ZTW with 66,000 miles and a 2.0L Zetec engine. The problem started after listening to radio about 20 min. With engine off while waiting for my wife. We started the car, drove about 1 quarter mile to another store where I dropped my wife at the door. When I started to accelerate, ABS and Brake warning lights came on and car tried to stall. I parked and shut off engine. After that, engine would not turn over. It clicked a couple times then nothing. We were able to jumpstart the car and drive home. A couple of cells in the battery were extremely low on electolyte (aftermarket battery - 2-3 yrs old) so I added water. Was able to start car repeatedly at this point with no dimming of headlights, etc.

Next day, borrowed a mutli-meter and tested the charging system/battery. The battery registed about 12.8V at rest and slightly better than 14V with engine running (lights, radio, rear defrost on) at idle speed. Drove around for a while to heat the engine good and rechecked. This time, meter showed about 10V at idle which was very gradually dropping. Revved engine to 2000 RPM and was able to get just above 11.5V. At idle, the meter continued downward to about 9V before I cut the engine.

That's the not so short story. My question is this: I am assuming that I need a new alternator. The fact that I apparently had to get the engine hot before the voltage dropped is confusing me. Should I be looking at something else before I replace the alternator?

3 Replies

TBOYD

MEMBER
4 POSTS

I worded my story badly. When I said a couple of battery cells were low, I meant low on electrolyte not voltage. Does that make a difference?

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Thursday, July 5th, 2007 AT 5:36 PM

TBOYD

MEMBER
4 POSTS

I do have a multi-meter and have checked all fuses. I checked with the multi-meter again last night after letting the car sit for 24 hours. The battery read 12.25 volts with nothing running. I started the engine and checked again. That time I got a reading of about 11.5 volts and dropping. The voltage never stopped dropping and, of course, dropped faster when I turned the headlights and fog lights on. I was able to bring the voltage back up to nearly 12 volts by revving the engine to 2000 RPM. The voltage continued to slowly drop at this speed. With the engine running, I should be getting better than 12 volts even if the battery is dead. Don't you agree?