Quote:
Originally Posted by SPL
Does anyone out there have a ScanGauge? I'm finding that my 12-V battery's voltage frequently drops below 12 V when my car is ON, but not READY. [I.e., two pushes of the Start button with your foot off the brake.] If you do have a ScanGauge, could you please read your 12-V battery's voltage under the above condition, say in the morning before you start the car after an overnight "sleep," and let me know the result? Normally, a properly charged 12-V battery's voltage should not drop below 12 V. As soon as my car is put in READY mode, my battery's voltage rises above 14 V, as should be the case.
|
I tried mine this evening and saw a pattern which may explain what you're experiencing:
At ON (but not READY), my scangauge recorded 11.9V, i.e. below 12V as well. As a matter of fact, as soon as I depressed the brake pedal (and the power button glowed green vs. yellow, indicating "go ahead & start me up if you want"), it dropped to even 11.8V or 11.7V... I tried it a few times, same results every time.
But here's the kicker: it was evening and I have my lights set to "AUTO", so they go on as soon as the car is turned to "ON" (even if w/o brake being depressed). Once I turned that auto-setting off and repeated the same steps, I got 12.1/12.2V in "ON" mode. Read: above 12V, just as you were expecting.
I forgot to see whether depressing the brake pedal would bring it down to 12.1V or 12.0V (or lower?), but that's probably moot by now. The likely reason you probably got below 12V once in a while are your lights draining power from the battery.
Mind you, I'm not an electrician but I did stay at a Holiday Inn last night...