$hawn

I thought I read somewhere, that scanner battery voltage readings will read lower then they should, I dont know, thought I read that somewhere though, anyways The alternator is about 8 months old, and on my auto x-ray scanner the battery voltage was reading mainly 12.8-12.9, then I turned on the stereo and it was about 12.7-12.9, and the highest I ever seen was 13.0-13.1. My understanding is that it should charge at atleast 13.5-14 volts correct? Anyone with a auto x-ray scanner whats your read. Thought I would ask before I exchange it.

Injuneer

I know the system voltage readout on my ScanMaster is definitely close to 1V lower than the dash voltmeter, and the data logger built into my MoTeC engine management computer. I've asked the question a few times, but never tracked down why the scanned voltage seems lower than the battery voltage or other measurements.

arnie

Using 2 vehicles for reference with the Auto x-ray as the scanner, I'll get about 14.0 at startup, and 13.1-13.3 on one, and 13.2-13.4 on another idling at oper. temps. with no accessories operating.

$hawn

Arnie, so your voltage seems low too, at least on a scanner, so maybe scanner voltage readings are 1 volt lower than actual. I wonder why it's like that? Thanks Fred and Arnie for the input.

turbo_Z

on my scanmaster ill see readings of 12.7-13.1 and the dash guage is always above 13 so the 1 Volt less theory holds with my car too.