Days of Broken Arrows said:
Think Hotwheels gave sound advice for question posed.
Also Guitarman for his revving. I do this, 10-15 cycles of 60 seconds at 2,000rpm then let idle for 30 seconds.
Hope your car was good D.O.B.A
As for testing your car batteries:
D.O.B.A (or anyone else with a suspect battery) Now is your time to plunge into the world of MULTIMETERS. Every real man should have one anyway!
If you don't already own one, i'm sure you can pick a cheap one up at an electronics store for roughly $5-$10 now.
Anyway, to test your battery:
Turn on the multimeter, select the DC volts setting
You need to put each of the two probes from the multimeter onto the two terminals of your battery(preferablly on the +ve(red) & -ve(black) sides,but dosen't really matter as you'll only get a -ve reading if you switch them)
Engine off: should read around 13.2-13.5 volts
Engine on (idling): should read around 14.2 volts
If your battery reading is under the 12.5-13 volt mark it's basically goosed, or soon will be!
Hi Mech
:sadwave:
Mate, the above is misleading in parts and in others just plain wrong.
First off the alternator will put out enough juice to top up a battery at idle. You look like less of a twat just leaving it running for ten minutes than you do sitting in it revving it for "10-15 cycles of 60 seconds at 2,000rpm then let idle for 30 seconds". You seriously mean you sit there with your foot on the pedal for over 15 minutes rather than just leaving it running?
As for the multimeter bit, a fully charged 12v battery will clock just under 13v. Stating that a battery under 13v is basically goosed is completely wrong.
The battery may read over 13v with the engine off if you've only just switched it off.
With engine running it should read between 13.5v to 14.5v depending upon alternator output.
The above only give an indication of state of charge. Your battery may still be so shagged that it can't deliver sufficient amps to start the engine. To check the CCA you need a load tester.