CRUISING ELECTRONICS E-Meter, Руководство пользователя

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Electric Vehicles (EV's)
Your Meter is the ideal energy meter for EV instrumentation. It not only
provides Volts, Amps, Amp-hours and Time Remaining, it adds two im-
portant bonuses: Kilowatt-hours and optional serial computer output.
If you design or work with electric vehicles or battery powered equip-
ment of any type, you should realize that Kilowatt-hours are a more accu-
rate measure of energy used than are Amp-hours. Here's why:
The term "Amp-hour" defines current (Amps) multiplied by time (hours).
Amp-hours is one way to state battery capacity. Amp-hours is not a mea-
sure of energy consumed by a vehicle. Energy is defined as:
Energy in Watt-hours = Voltage x Amperage x time.
Consider two examples: First, assume we have a 120 Volt battery that
supplies a 100 Amp load for 1 hour. At the end of one hour, 12,000 Watt-
hours (12.00 Kwhrs) will have been consumed. In the same period of
time, 100 Amp-hours will be used.
But now suppose we have a 240 Volt battery supplying a 100 Amp load
for one hour. What happens to the math? Well, 24,000 Watt-hours (24.00
Kwhrs) of power have been consumed. The Amp-hours consumed is the
same as the first example, 100 Amp-hours, but twice the energy has been
consumed!
That's why electric vehicle efficiency is judged on Kilowatt-hours. A Kilo-
watt-hour is a 1,000 watt load for a period of one hour. You buy kilowatt-
hours from the power company (to keep the lights on in your home) at a
typical cost of $0.05 to $0.15 per KWh. By comparing the cost of Kilo-
watt-hours from the electric company with Kilowatt-hour consumption
of an electric vehicle, you can accurately judge EV operating costs.
Refer to Owner's Manual for instructions on use of the KWh display.