Mike,

Sorry I took this long to answer your question; I just started it for the first time after getting it back together this afternoon.

Immediately after it starts, with the glow plugs still on, the voltage is 11.4.
As soon as the glow plugs turn off, the voltage now goes to 14.3+ (At Idle!).

This is with a 2/0 gauge cable between the positive terminals of the batteries, a 4 gauge cable between the alternator positive terminal and the positive terminal of the passenger battery, and a DC Power 185 amp alternator. I also upgraded the fusible links in the alternator cable from two 12 gauge in parallel to three 12 gauge in parallel. The 2 link factory configuration was good to 160 amps; 3 links will support 240 amps.
I'm happy with that new alternator...I think it might make my batteries last longer, since it begins charging them at idle as soon as the glow plugs turn off. The OEM alternator was not charging the batteries until I got the RPM's above 1500. It was taking quite a long time to get the batteries charged back up after being depleted from starting the truck.


If your going to repair the cable between the positive terminals of the batteries, I would recommend you at least increase the gauge from 1 gauge to 1/0 gauge. I increased mine to 2/0 gauge, but it wasn't easy to solder and the cold solder joints on both ends of the cable were the reason mine failed.
I changed the way I terminated the cables this time. I put solder lugs on both ends. The previous setup was soldered directly to the original OEM cable terminators. I highly advise against soldering to the OEM cable terminators for 2 reasons:
1) It's near impossible to get it hot enough to make a good solder joint, and
2) A solder joint alone is not mechanically strong enough to hold up to repeated flexing. This is why mine eventually failed.

My recommendation is to use copper solder lugs because they're easier to solder and will hold up to repeated flexing.