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Battery Light at high speeds
#1
So when im accelerating to get on the highway the battery light will come on ..... it puzzles me because the battery and alternator are new , just installed about two months ago. Any ideas on why this is happening? The light only comes on at high speeds. Also when the air conditioning is cranked and car is idling the whole car looses power..... (idle jumps up and down) upon recieving a boost from someone the car started back up..... then when taking it home the car died when stopped at a light. I recharged my battery and everything seems to be working fine, although im afraid to put the AC on. Im suspecting that the alternator could be bad....?
2002 SVT Focus
Procharger @ 10psi , Clutch Masters Stage 3 Clutch,Stainless Borla Exhaust, Ebc dimpled + slotted rotors and brakes ,Russel Stainless brake lines , Koni adjustable shocks ,Eibach Sportline Springs , CFM short throw shifter , Euro Grill , CFM 65mm tb , Mach Headlights , MSD Coil ,SCT Dyno tune @ steeda , Volant Intake .  
-2003 SVT Wagon - Euro Conversion , currently retired
Svt side skirts , st170 front bumper , mach headlights , spax rear adj shocks , focus sport rear springs , volant CAI , Roof rack delete , Street edition Spoiler , MBRP exhaust , Eibach front swaybar , shorty shifter and lots more to come!                             .
2011 SES - daily driver will be modded soon .                                                                                                                                                        
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#2
Did you replace the belt and check the tensioner? That would be my first place to start. If the belt is stretched or the tensioner is seized then the belt will slip at high RPM. Check the belt (cracks and rips -- in case you mis-installed it when the alternator was replaced) and make sure it's tight, and pry the tensioner (like you were installing a new belt); it shouldn't be too easy to turn it, If it's floppy it needs to be replaced.

Apart from that, it could be a bad voltage regulator, which (IIRC) is built into your alternator. The only way to know for sure is with a multimeter.

Edit: One possible reason the car died with the AC on is because when the AC compressor kicks on it puts more load on the belt making it slip more and making the alternator produce less power.
TEAM PITA: Don't settle for a wannabe, only accept the real deal.
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#3
ya i have , the belt and tensioner was replaced early may. I will check over everything when i get a chance. Im thinking that the altenator may need to be switched... the one that is in right know came off of an svt.... i was thinking that it would be fine but im starting to think maybe not haha i havent actually checked into if the altenators are the same for the svt and just a regular focus. I just assumed that they would be?
2002 SVT Focus
Procharger @ 10psi , Clutch Masters Stage 3 Clutch,Stainless Borla Exhaust, Ebc dimpled + slotted rotors and brakes ,Russel Stainless brake lines , Koni adjustable shocks ,Eibach Sportline Springs , CFM short throw shifter , Euro Grill , CFM 65mm tb , Mach Headlights , MSD Coil ,SCT Dyno tune @ steeda , Volant Intake .  
-2003 SVT Wagon - Euro Conversion , currently retired
Svt side skirts , st170 front bumper , mach headlights , spax rear adj shocks , focus sport rear springs , volant CAI , Roof rack delete , Street edition Spoiler , MBRP exhaust , Eibach front swaybar , shorty shifter and lots more to come!                             .
2011 SES - daily driver will be modded soon .                                                                                                                                                        
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#4
(07-02-2012, 01:59 PM)2000zx3sct Wrote: the one that is in right know came off of an svt.... i was thinking that it would be fine but im starting to think maybe not haha i havent actually checked into if the altenators are the same for the svt and just a regular focus. I just assumed that they would be?


Your assumption is correct. Ford parts lookup shows the identical number for both regular Zetec and SVT - 98AZ10V346EARM.
2008 Fusion SEL MTX - DD1 * 2009 Fusion SEL - DD2 * 2007 Focus ZXW - R*I*P * 2004 Focus ZTW CD Silver - sold * 2004 Focus ZTW Black - sold * 2003 Focus ZTW Black - sold * 2001 Focus ZTW Gold - sold * 2000 Focus SE Wagon (ZTW option) - Black - sold * 2000 Focus SE Wagon (ZTW option) - Gold R*I*P

2003 Focus ZX5 infra-red Track Rat - R*I*P
2003 ZX5 CD Silver Track Rat - retired, but still in the driveway


New track rat: 2000 ZX3, Atlantic Blue * JRSC with lots more to come

* New Zetec crate motor - NFG - thanks Topspeed *
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