Let me guess... Autometer sells voltmeters but not ammeters :-)
They both have their place, they both require proper interpretation.
Voltmeters are cheaper and easier to install (hmmm, is that why
'newer' cars use voltmeters? Or did car designers of the 50's and 60's
not have a clue?)
> On a typical flow meter, all output must be directed through the
> device to obtain an accurate reading. In the ammeter's case, that means all
> the alternator output used to recharge the battery must first be routed
> through the ammeter under the dash.
Check out the '66 Mustang. Ford actually understood the use of a
SHUNT. The dashboard ammeter carries only a fraction of the current,
most of it passes thru what is essentially a precision very-low-value
resistor under the hood. No heavy-gauge cable, no fire danger. And
if the ammeter somehow actually blows, the car still runs :-)
> All this might be worth the hassle if the ammeter produced reliable
> information...
> In summary, there is no chance for misinterpreting a voltmeter's readings
> as can happen with an ammeter.
Uh huh....
How about a battery with a shorted cell? The voltmeter will make it
appear that the alternator is dead (low voltage). The ammeter will
indicate excessive current draw ('hey Joe, your battery isn't charging!")
Or a sulphated battery (i.e. old and won't take a charge). The voltmeter
will say 'things are great', the ammeter, if you pay attention, will indicate
a problem due to a lack of the expected 'high then taper off' pattern.
Just an alternate opinion...
-- John
John F Sandhoff sandhoff@csus.edu Sacramento, CA
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