Alternator failure?

Not necessarily. The only thing that the battery light is designed to detect reliably is if the alternator belt breaks -- i.e., engine running (or key "on"), but alternator not spinning. Often it will come "on" if the alternator system has an internal electrical fault, but not always.

 

Steve- Should be easy to check. First thing I would check would be to make sure the ground cable is well grounded and the battery cables are tight and not corroded. After that someone can check and see if the alternator is putting out correctly. If you do not have a 550 workshop manual, you can download one from ferraridatabase.com.

 

Sounds like a failing/failed voltage regulator, but check the cables as Taz mentioned.

It's almost exactly the same as some Lexus's alternator, can't remember which one but an alternator rebuild shop can tell.

 

Steve- Here is a battery document I put together. Optima batteries have had reliability problems since Johnson Controls bought them and moved production. My car has an Interstate MTP-91 in it (pushing 4 years now), and one of our FChatters just replaced his 9 year old MTP-91 with another one. Warranty is 85 months.

The overkill batteries are the Odyssey and Braille absorbed glass mat batteries shown in the document. Some of them can be deep discharged 400 times and recharged with no degradation. Note their warranties are not outstanding, however.

Yell if you have any questions. Except about Optima batteries.
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I had the Braille B7548 AGM Overkill Battery installed in my 550 nearly two years ago. It's doing fine. I paid $165 for it.

 

+1 with Braille. Installed in 575 over a year ago, no issues yet. Cost just over $200.
Their customer service was best I've experienced anywhere in recent history.

Bill
FL

 

Right, Bill. I figure if they can last here, it can last in my 550...
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I may have to get one of those Braille batteries in five or six years when my Interstate gives up, it's already three years old.

 

I'll give you mine when the time comes, Dave.

 

Steve- Reports of the cost of Braille batteries have been greatly exaggerated, unless you want one of their lithium batteries. Their AGM batteries are affordable and the B7548 even has the terminals properly arranged, so no J Hook (bad image here) required.

 

My last Interstate lasted for 5 years, bought an new one for 90 bucks, why over do it? They are just batteries for cry in out loud, not that hard.
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Where's your hold-down bracket, fou?

I've since installed a new heat shield for the battery. My 1999 550 (Build #32821) was supposed to have one. It got lost along the way.

 

Understand Fou's comment of "why over do it". And I am not pushing the Braille battery, just reporting a good experience with them.

IMO, as car people our nature is to over do it, owning a Ferrari is to over do it. Owning something like a Braille, Optima, or high end Interstate is just an insurance attempt at one less problem down the road.
Being one step more peculiar, I liked the fact that the Braille was black and the stickers/labels peel right off allowing it to be heard and not seen...

Bill
FL

 

Steve, 14 volts and over is NORMAL for a running engine and functioning alternator. Mine runs at 14.4 volts. MAYBE the alternator will put out 13.7 volts at low idle but it should always be over 14 volts while the engine is running. I would look under your car at your alternator and see if it is dripping oil. Oil in the alternator is EXTREMELY common in the 550, from timing cover leaks as well as a bum A/C compressor, and over time it erodes the brushes at the back of the alternator.

I second Fou's opinion. I just put the original MTP-91 Interstate back in and keep the car on the battery tender. I'm not driving a tank. Just a sportscar

 

I had just put in a new one and was documenting it for my file. Here it is strapped in, they undid it and tightened it down for me last service this past month. I keep a photo record of all service with the files so to confirm all services in the future. It was a little misleading without the bracket, but to just confirmed all was done. My 575 file is already larger than my Porsche and other cars, but I am weird that way.
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Steve,

Braille has four lines of Motorsports batteries: No-Weight, Carbon Fiber, Endurance and Lithium.

Here's their website: http://www.braillebattery.com/

Barry

 

Steve- That battery is pushing 1000 CCA and can be deep discharged and recharged hundreds of times, so think you will be very happy with it.

 

Right, Terry. As you can see in the picture I posted, I have a Schumacher SE-1-12S Battery Tender mounted nearby which works well with Braille B7548 AGM battery. The high cranking power is evident each time I start the car.

It's a maintenance-free battery so you don't have to worry about it. AGM batteries are pretty much standard in the military.