Oh geeze, like I need another project.
I copied this from the alco axle paperwork I have.
System voltage is measured at the magnets by connecting a volt
meter to the magnet lead wires. Connect the trailer wire connector to
the tow vehicle. The engine of the tow vehicle should be running. The
voltage should start at 0 volts. As the controller bar is slowly actuated, it
should gradually increase to about 12 volts. If the increase is not
gradual the brakes would apply instantaneously. The lower the
threshold voltage the smoother the brakes will apply.
System amperage is the amperage being
drawn by all brakes on the trailer. Single
magnet amperage can be measured with an
ammeter attached at the magnet lead wires.
Follow procedure above. Each magnet should
draw about 3 amps at 12 volts. To check the
total system the controller output to the brakes
must be disconnected and the ammeter put
into series in the circuit. With magnets cold
(70o F), the ammeter should read about 3
amps for each brake or 12 amps for a tandem
axle trailer (4 brakes). (Amperage is affected
by the length and gauge of wire between
ammeter and brake as well as between the
power source and brakes.)
So I found a voltage drop calculator on line and with 14 ga wire and a 25 ft one way run the drop is nearly 16%.
12 ga reduces the drop to 10%
10 ga the drop is a little over 6%
8 ga drops to just under 4%
6 ga is about 2.5%
well you get the idea.
Here is the calculator I used
http://nooutage.com/vdrop.htm
So,...... looks like I got another project.