Specifications

52
5.2 Charging System
Because high efficiency is a greatly desired characteristic of the project generator it was
determined that the greatest use of a charging circuit would be with a maximum power
point tracking system. This was chosen over the other multi stage charging methods
because the efficiency of the maximum power point tracking system is over thirty
percent more efficient than other conventional charging circuitry methods. With a overall
efficiency around ninety seven percent the maximum power point tracking system is
hard to compete with in terms of efficiency.
With the maximum power point tracking systems‟ method of being able to track the
optimal voltage and current combination for use when supplying a charge to a battery it
was a clear choice over other systems that would not be able to supply the battery with
as much charge as an MPPT system. The greater supply of charge would mean that the
specified battery could be charged faster while at the same time be in a passive state of
constant charging without even needing to worry about a float stage since the maximum
power point tracking system always delivers the optimal supply charge to the battery.
Although a maximum power point tracking system is more expensive to other multi
stage charging systems the greater efficiency leads it to be the clear choice in charging
circuitry over other methods.
Part of the reason that a maximum power point tracking system is more expensive to
the other methods is because of the sheer complexity of the circuitry involved in the
design. That is why it was decided that is why a commercially available maximum power
point tracking system was to be used in the project simply because of the man hours
and expense it would cost to try and create a maximum power point tracking system
from scratch. Many vendors were looked at when considering what kind of maximum
power point tracking system to buy. Below is a table of possible charging systems that
were considered for the project and their pros and cons.
MPPT Charge Controller Comparisons
Manufacturer
MidNite
Outback
Blue Sky
Xantrex
Morningstar
Apollo
Model
Classic 150
FM60
FM80
3048DL
XWMPPT6
0
TSMPPT60
TS80
Rated Amps
80-96
60
80
30
60
60
80
Max Operating Voltage
150
145
145
112
140
150
112
Max Battery Voltage
72
60
60
48
60
72
48
Solar Use
X
X
X
X
X
X
X
Wind Use
X
Average Price
850
749
849
649
685
793
849
Display Included
X
X
X
X
X
X
X
GFI
X
X
Oscilloscope Use
X
X
Battery Status Meter
X
External Shunt
X
Figure 40 – MPPT Comparison Chart