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Lil bastard · 03-08-2010, 04:40 PM

I suspect you've had a bad alternator all along which is why the other battery failed to start the car. The arc is surprising unless you connected the negative (-) cable first then the positive(+), or with the key in the ignition - big NO-NO that.

When connecting the new battery, you likely blew another set of diodes (3 prs. total).

Also, did you charge the battery prior to installing it? FYI, batteries straight from the store are not at 100% charge due to shelf life. It's always best to charge the battery independently first and not rely on the alternator - they are not intended or really designed to fully charge a battery. Their function and design is to run the car and it's accessories while topping off the charge of the battery dissapated by the start-up.

If your alternator were newer, I recommend just swapping the diode pac - available sparately. But since it's 9 yrs. old, I'd opt for replacement so you have fresh bearings, brushes and windings, it's the best way to go.

BTW, a battery in top consition should show no less than 12.8 volts and more like 13.0-13.2VDC. And for the Bosch alternator, the output spec is 13.5-14.5VDC.

Cheers!

03-08-2010, 04:40 PM	#8
Lil bastard Registered User Join Date: Feb 2008 Location: Du Monde Posts: 2,199	I suspect you've had a bad alternator all along which is why the other battery failed to start the car. The arc is surprising unless you connected the negative (-) cable first then the positive(+), or with the key in the ignition - big NO-NO that. When connecting the new battery, you likely blew another set of diodes (3 prs. total). Also, did you charge the battery prior to installing it? FYI, batteries straight from the store are not at 100% charge due to shelf life. It's always best to charge the battery independently first and not rely on the alternator - they are not intended or really designed to fully charge a battery. Their function and design is to run the car and it's accessories while topping off the charge of the battery dissapated by the start-up. If your alternator were newer, I recommend just swapping the diode pac - available sparately. But since it's 9 yrs. old, I'd opt for replacement so you have fresh bearings, brushes and windings, it's the best way to go. BTW, a battery in top consition should show no less than 12.8 volts and more like 13.0-13.2VDC. And for the Bosch alternator, the output spec is 13.5-14.5VDC. Cheers! __________________ 1990 Porsche 964 Carrera 4 Cabriolet 1976 BMW 2002 1990 BMW 325is 1999 Porsche Boxster (gone, but not forgotten) http://i933.photobucket.com/albums/a...smiley-003.gif Never drive faster than your Guardian Angel can fly! Last edited by Lil bastard; 03-08-2010 at 07:34 PM.