4.
Display Information
In addition to the screens discussed in
section 1
, there are 5 others
that show a range of statistical information relating to the energy use
of your vehicle.
4.1 Display Screen #3 - Power Information
Watt-hrs:
This is a measure of the total energy that has been pulled
out of the battery pack. One watt-hour is 1/1000th of a kWh and
slightly less than one food calorie. To a first approximation, the watt-
hours available from a battery should be equal to the voltage of the
pack multiplied by its amp-hours, but it will typically be less than this
because of voltage droop caused by large current draw. Notice that
only the positive watt-hours pulled from the pack are recorded.
During regenerative braking when the watts are negative, the watt-
hours value does not decrease.
Wh/km
or
Wh/mi:
The watt-hours used per unit of distance travelled
is a measure of the average energy efficiency of your vehicle. With
this figure, you can readily quantify how different riding styles impact
your range and predict with high accuracy the expected travel
distance with any particular battery pack.
The Wh/km or Wh/mi figure is calculated taking into account current
that may have flowed back into the battery pack from regenerative
braking. The actual formula used is:
In order to reduce computational round-off errors, the figure only
displays after a total distance of 0.5 km or mi has been travelled.
4.2
Display Screen #4 - Regenerative Braking
The next screen shows information that pertains to negative current,
that is current flowing into the battery pack.
% Regen:
The percent regen indicates by how much your range
was extended as a result of energy returned to the battery from
regenerative current. Most direct drive vehicles that do not have
Wh
Dist
FwdAh - RegenAh
Wh
FwdAh
(
)
1
Dist
=
7
