On my 2188 it will show it charging for about the first half-hour every morning then for the rest of the day it just keeps getting lower and lower. Then toward evening it shows only around 12.2.(as read on the volt reading ont the yield monitor.) I never run with the lights on for very long. It always starts in the mornings, but just barely. My batteries are two years old. It started after sitting all winter, so the batteries never were dead. I have cleaned both the positive and ground connections on the cab. I just put a new alternator on, no difference. It just seems like every 21/23 I've ever been around is like this, I just would like to see them charge better. Sometimes at the end of the day I've had to turn off the lights and AC/fan to get the separator/feeder to engage. No I haven't dove into it with my multi-meter, I need to do that. There has to be a bad connection or cable or wire somewhere. Or is it just that those alternators loose that much efficiency when they get hot?