Jasen Betts wrote in a message to JAY EMRIE:

 JB> a moving coil fuel gague can be handy too - when the tank's getting
 JB> low you can "see" the fuel sloshing round :)

Yeah,  this one car of ours reads differently depending on whether you're
going up or down a hill,  made for interesting travels on a recent trip to
WV...    :-) 

 JB> Otoh electronic ammeters can be installed using the batteries earth
 JB> cable as a shunt...

I have a couple of articles sitting here that describe how to build those, 
and should probably have a go at it one of these days.

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