1997 Chevy Blazer short? Battery won't hold over nite cgar

Tiny
DGOSKE16143
  • MEMBER
  • 1997 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 14,000 MILES
Hello and merry christmas and thanks for your help.I hope. Any way, mechanic put meter on battery and alternator, says battery is good and alternator is charging at 12 1/2 volts. Battery connections are clean and tight, 'check engine light'. Not on, no interior lights are on, ran truck for an hour to charge battery, started up 4 hours later but 'not' like usual and could tell the battery was drawing down when I started it up and did not hold the charge over nite, tried to start it this morning. Click click click click. Hope I have given you enough information, thanks and have a happy holiday
Sunday, December 20th, 2009 AT 1:20 PM

1 Reply

Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
Welcome to the forum, happy holidays. 12.5 volts is not good output from the charging system. I like to see well over 13 volts at idle, all electricals turned on. Anything under 13 I consider a weak charging system.

If the battery is down, take it off and get it charged, don't use the alternator. I can't rule out a battery drain, normal may be around.030ma, no where close to 1/2 amp.
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Sunday, December 20th, 2009 AT 2:10 PM

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