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mark houghton mark houghton is offline
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Join Date: Jul 2008
Location: Central Washington State
Posts: 3,861
Amp up the ol' bat (not your woman)

So, outside of a fruitless exercise to energize the ol' bat into a productive member of society, how about your car battery? Mine is decidedly old and about due for replacement, showing a fair amount of sulfating when I look down inside the wells. The last couple of days, after a good 25 mile commute, when I open the sunroof for "fresh" air, I get this stink reminicent of H2S. For those with a modicum of chemistry education, that's good old hydrogen sulfide, aka rotten egg smell. Nothing in a 930 sans-cat should smell like that, other than a battery boiling over (or a dead freakin' mouse in the air ducts, which is possible).

I took the opporunity to leave her running when I got home, slapped the trusty old digital voltmeter on the battery, and measured 15.8 charging volts. To me, that's about 1.0 volts too high considering it had been charging for many miles. No visible bubbling-over of acid, but suprised at the high voltage - and that with the outside air vent fan running on low.

Could just be that all that sulfation is causing an excessive draw on the battery with the charging circuits over-compensating. Don't know, never measured it before. Anybody put a DVM on their battery lately...give me a baseline???
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 07-13-2011, 05:34 PM
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