For anyone wanting a cheap easy way to monitor voltage, stop by Autozone and check out the Battery section. They have small LCD voltmeters designed to plug into a power outlet or cigarette lighter, made by Vector Mfg, cost $12.

I picked one up and gave it a try. Had to turn the screen sideways to clear the shifter knob when in park with the ashtray fuly extended, and a little bit of a loose fit in the socket. But it worked, and agreed with my multimeter as to what system voltage was running at idle.

With key in position 1, battery voltage read 12.6. Key in position 2, glow plug light on, dropped to below 11 volts (gawd, those plugs pull some power).
Engine started but glow plugs still on, 12 volts. As soon as glow plug relay kicked out, jumped up to 13.6 volts. Driving down the road at 2000 rpm, 13.9 volts.

At least that answers whether or not the alternator and voltage regulator are in good shape.

It may look cheesy, but at least I have a way to monitor the charging system until the day comes when I can put a proper set of gauges in the beast.

__________________
Just say "NO" to Ethanol - Drive Diesel

Mitchell Oates
Mooresville, NC
'87 300D 212K miles
'87 300D 151K miles - R.I.P. 12/08
'05 Jeep Liberty CRD 67K miles
Grumpy Old Diesel Owners Club

When I was doing some electrical troubleshooting, I used the lighter socket as the point to put my clip-probe leads from my trusty Fluke DMM while I was driving around. People gave me some weird looks with that yellow case sitting on the dash dangling the leads down over the front of the dash.

As a byproduct of the troubleshooting, I did observe the "after glow" phenomenon on the DMM, when the voltage took a second jump a minute or two after the initial glow plug dip-return.

Rgds,
Chris W.
'95 E300D 222K

I watch that on my gauge all the time 12.6v position 1, 11v glowing, 10ish for a split second during cranking, then back to 11.8ish running with afterglow, then to 13.5 after about 2 mins, then up to 14.1 after that and it stays there unless I turn on every single solitary electrical device. Very cool.

Here's a pic of mine I snapped with my cell phone a while ago...it was at night, and afterglow was still going....

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)