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Old 07-25-2012, 12:42 PM
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YerDugliness YerDugliness is offline
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Join Date: Sep 2006
Location: No city...only 118 residents in Manter, KS
Cobra Make, Engine: Cobra Auto Works body, Ron Godell Racecars chassis, 1989 Mustang GT 5.0 HO (converted to carb), W/C T-5, 3.73's in a Ford 9" Traction-Loc.
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Default Is my alternator overcharging my battery?

Well, I got stranded by the Cobra yesterday, battery went bad (checked on a load-reading machine, verified the battery would not hold a load).

I had noticed that there were a few things "fishy", for lack of a better term. For example, the needle "voltage" gauge would jump by 1 or 2 volts every time the turn signal flashed, and other electrical items weren't working very well, like the fuel gauge.

I pulled the battery when I got home, charged it until the charger could no longer deliver 2 amps, and tried to start the engine. Click, click, click...sounded just like the relay does when a Ford starter is bad. Next I started working on grounds around the car, found all but one to be very tight, and then tightened that one up.

I had a recently purchased but unused 375 CCA battery sitting around, so I topped off the charge and put it in. The Cobra roared to life, the fuel gauge now works, there is no wavering on the Voltage gauge (the ammeter is not working...a job for when the dash comes out), and the charging rate with no lights, no fan, just the engine running runs above 14 volts, not quite 15. When I turn on the large Spal puller fan, the voltage meter drops below 14, but only slightly. With the previous battery the charging voltage was rarely at 14 and dropped to 12 as soon as the fan was turned on.

If it matters, fuel filter is a Mallory Series 140 Comp Filter and the fuel pump is a Mallory series 110 Comp Pump. Naturally, the pump runs any time the switch is turned to a setting that energizes the electrical system.

My concern is that I might be overcharging the battery. The one that failed was a Bosch unit, still looked to be in great shape although it was probably at least 4 years old, maybe more (the battery was in the Cobra when I bought it).

I didn't have the alternator checked for output, but can if anyone thinks that my battery failure might have resulted from overcharging.

If there is one thing I have learned about our component cars, it is to check the grounds anytime ANY issue arrises....I must admit the needle on the voltage gauge is much more stable now than before (no falling and rising with the turn signals), that might be the result of my ground-tightening efforts, or it might be because the battery I just put in the trunk is in better shape than the old Bosch unit.

Any advice????

TIA for whatever help you can provide!

Cheers!

Dugly
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