Hi, I have a 1988 300SEL and I replaced the voltage regulator and when I first start up the car, it charges a little over 14, which is great. Once the car warms up it starts to charge less. Sometimes it stays around 13.3 but as the car warms up and has been driven a little, at idle it charges at 12.3-13.1 and rarely goes above 13.3 after fully warmed up and driving around. Not sure what it should charge at at idle, nor what it should charge at normal driving. Any help would be appreciated. I did order a new (rebuilt) alternator but am waiting on a pulley I ordered for it. Worst case I'll just drop this one in, but does anyone know any other electrical reason why the charge may be varying that much?