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TrakMax 30L User Manual
Revision 1.0
4.1.1
How MPPT Works
A PV module is a constant current type device. As shown on a typical PV module voltage vs. current curve,
current remains relatively constant over a wide range of voltage. A typical 75 watt module is specified to deliver
4.45 amps @ 17 volts @ 25 C cell temperature. Conventional PV controllers essentially connect the PV array
directly to the battery when the battery is discharged. When a 75 watt PV module is connected directly to a
battery charging at 12 volts, the PV module still provides approximately the same current. But because output
voltage is now at 12 volts rather than 17 volts, the PV module's power production is artificially limited and the
75W PV module only delivers 53 watts. This wastes 22 watts of available power.
TrakMax's MPPT technology operates in a very different fashion. Under these conditions TrakMax calculates
the maximum power voltage (V) at which the PV module delivers maximum power, in this case 17 volts. It then
operates the PV module at 17 volts which extracts maximum available power from the PV module. TrakMax
continually recalculates the maximum power voltage as operating conditions change. Input power from the
maximum power tracking controller, in this case 75 watts, feeds a switching type power converter which reduces
the 17 volt input to battery voltage at the output. The full 75 watts which is now being delivered at 12 volts would
produce a current of 6.25 amps. A charge current increase of 1.8 amps or 40% is achieved by converting the 22
watts that would have been wasted into useable charge current. Note that this example assumes 100%
efficiency to illustrate the principal of operation. In actual operation, the power boost will be somewhat less.
4.2 P
OWER
Once the controller is properly connected to a battery, the solar controller will start automatically. The main
display interface will appear in the LCD and the current PV / Solar panel voltage and current will be displayed.
Press the 'UP' or 'DOWN' buttons to cycle through the six different interfaces available on the TrakMax
controller. The cycle pattern of the interfaces is presented in Section 4.5 and some of the parameters are user
configurable. When any key is pressed, the LCD backlight will automatically turn on. The backlight will
automatically turn off when the controller is idle for 30 seconds.
To power down the controller, cover the solar panels and disconnect the PV input to the controller. Remove the
battery connection and check the charge controller status. Once the LEDs and LCD display turn off, the charge
controller is shut off.
4.3 LED M
ODES
The TrakMax has four LED indicators to quickly observe the operating status of the controller.
Page 17 of 29
Current / Power vs. Voltage Characteristics
windynation
05/06/2015
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