Here are some readings I made when I replaced the alternator in my 300E. The original stock 70A alternator was failing and I upgraded to a new 80A unit. The original 70A still worked, but only barely. Under load, it couldn't produce enough juice to keep things going and charge the battery.

BEFORE (70A):
rest - 12.85V
idle - 13.86V
idle with full load = 11.87V
full load, 1500 RPM = 11.74V

AFTER (80A):
rest = 12.88V
idle = 13.97V
idle with full load = 13.56V
full load, 1500 RPM = 13.94V

__________________
Chris
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired

"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon