[Boatanchors] Panel Meter Circuit?

[W2HX]

Hi all,

I am doing a battery project, installing 28V battery system in a 12V vehicle with DC-DC converters and charging circuits, etc.  I want to use some traditional round analog meters to monitor voltage and current.  So I picked up a nice expanded scale (24V to 30V) panel meter which can be seen here:

http://www.w2hx.com/x/1967LRS2/V-Meter.JPG

I guess in my naiveté I assumed that this would read volts directly. Well, no such luck!  Here's what I know about the meter. First, its resistance reads about 230 ohms. Second, full scale (30V reading) appears to be about 360 mA (more precisely, 0.36 A - my ammeter does not have any more resolution than hundredths of an amp). It is very hard to measure the low end of the scale, perhaps 0 mA.  To the best I could, I measured the current that corresponded to each voltage marking on the meter.  Here is the result:  http://www.w2hx.com/x/1967LRS2/MeterRange.JPG  It looks pretty linear.

First Question is. How do I build a circuit that when attached to my battery will show the right voltage? 
Second Question is. Are there expanded scale meters that will read direct volts? Or do they all behave in this way? 

Thanks!
 
73 Eugene W2HX