Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Boxster General Discussions

LinkBack Thread Tools Display Modes
Old 12-15-2008, 03:36 PM   #1
Registered User
Join Date: Mar 2007
Location: Ohio
Posts: 1,626
Another electrical system question

This is an offshoot from my “Battery choice” thread.

Having been pretty convinced my battery was dead or dying, I had disconnected it from the cables in the car. (I was curious what it weighed.) I decided to charge it on a trickle charger for a few hours. A few hours after finishing that, it dawned on me that I had this analog multimeter, so I dug it out and checked the battery. It read better than 12V. Decided to put it back into the car, which started up nicely afterwards. (A couple days ago, I was left stranded away from home when the engine---having started an hour earlier---wouldn’t crank.) Went for a drive, pretty much everything was fine. Got back, shut her down, checked the voltage again. Again, it was over 12V. The question: the part that was not “fine” on my drive was the fact that the battery light came on (and stayed on).

Suggestions as to why? Is it probably just due to a bad battery, or do I likely have something more serious, like an alternator problem? Or is it impossible to speculate intelligently without additional diagnostics?

Thanks for any ideas.

Frodo is offline   Reply With Quote
Old 12-15-2008, 05:04 PM   #2
Join Date: Mar 2006
Location: Seattle Area
Posts: 3,011
If you take it to an auto parts store, they can test the health of the charging system (alternator) and the battery's ability to hold a charge.
blue2000s is offline   Reply With Quote
Old 12-15-2008, 05:26 PM   #3
Registered User
Join Date: Mar 2007
Location: Ohio
Posts: 1,626
Shazam! Why didn't I think of that?!

Frodo is offline   Reply With Quote
Old 12-15-2008, 05:51 PM   #4
Registered User
Jaxonalden's Avatar
Join Date: Mar 2008
Location: Oklahoma City
Posts: 1,209
Nice thing about a load bank from an auto parts (AutoZone) store is it's free!! And they'll tell you what part is bad.
Sadly on the outside looking in.
"Drive it like the Doctor ordered"
Jaxonalden is offline   Reply With Quote
Old 12-15-2008, 06:38 PM   #5
Registered User
Lil bastard's Avatar
Join Date: Feb 2008
Location: Du Monde
Posts: 2,199
You really s/b seeing 13+ volts if the battery is healthy. 6 wet cells, each producing about 2.2 volts wired in series.

If the battery is hooked up and the car running, you s/b seeing 13.5-14.5 volts for the oem bosche alternator.

If not, check cables for resistance and load test the alternator and battery. As mentioned, several parts stores will do this for free.

1990 Porsche 964 Carrera 4 Cabriolet
1976 BMW 2002
1990 BMW 325is
1999 Porsche Boxster
(gone, but not forgotten)

Never drive faster than your Guardian Angel can fly!
Lil bastard is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -8. The time now is 04:53 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page