help! charging problem!

[jfryjfry]

i put the big help plea here:
broken down on my wife... is this correct voltage???

but the short version is that I'm out of town, my wife is driving the truck and it lit the battery warning light and wouldn't start, just click.

sounds like a bad alternator to me, and according to the vin, it's a single alt system.

so i had a friend put a new alternator in and the voltages don't sound right for a healthy system:
12.8 at the battery at idle, 13 at the alternator at idle, rising a little when the engine revvs up, and reading 12.5 with the motor off.

thoughts????
i'm not looking forward to her driving it right now and i'm not going to be home for another week. ugh.

thanks so much for any help/ideas!

[d7rxr]

read other posts. Just tell her to take it out and drive it a while, 30 minutes or so and see if it recharges the batteries.

[SCUFFY828]

if voltage is getting checked just as soon as it started then the glow plugs are still on and its gonna read a little low , crank the truck and let it idle for at least 2 minutes , long enough for the glow plugs to go off , then see what the reading is , may even need to put some miles on it , if the batteries are still weak and alternator is working hard it can read low as well, may even go drive the truck awhile then check it