Originally Posted by hellosailor
slowbut, the question is, just how accurate is that little meter?
Probably pretty accurate. Multimeter hardware isn't expensive and DC voltage is the easiest thing to measure. At work we have all fluke meters but at home and the boat I have 3 of these:
As for the OP's question what Mainsail and Hello said are exactly right. You can't have voltage drop without current. If there's no current between where you're measuring and the battery it will be 100.00% accurate.
To put it in perspective a regular self-powered multimeter has 10+ Megaohms equivalent input impedance - you could measure your DC voltage a hundred miles away with 16 gauge wire and it would be less than 0.1% off due to voltage drop from the meter.