BoatBanter.com - View Single Post - And Aw a-a-a-a-a-y-y we go!

Jeff

* wrote, On 7/24/2007 6:09 AM:
....

You can use it to check everything - charging? It will climb up to
about 14.4 volts and then drop off to about 13.6, or if you are using
a manual charger you can monitor voltages and switch the charger at
the appropriate time. How much power are your nav lights using just
switch them on and check the voltage. Ho! Ho! Turned the lights on and
the voltage driopped 0.1 volts at 12.7 volts. A little math and you
know how much power yout lights draw.

What math is that? How does the voltage drop at the battery tell you
the Amperage its delivery?

BTW, I agree about the DVM, its essential on any boat that has more
than a minimal electrical system. Better yet is an Amp-hour meter,
certainly pricey but worth every penny if you have larger loads, such
as a fridge, and tend to live off-grid.