Epsolar eTracer ET4415BND, Operation Manual

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13
4 Operation
4.1 MPPT Technology
The eTracer-BND utilizes Maximum Power Point Tracking technology to extract
maximum power from the solar array. The tracking algorithm is fully automatic and
does not require user adjustment. eTracer-BND technology will track the array
maximum power point voltage (V
mp
) as it varies with weather conditions, ensuring that
maximum power is harvested from the array through the course of the day.
· Current Boost
In many cases, eTracer-BND MPPT technology will ‗boost‘ the solar charge current.
For example, a system may have 8 Amps of solar current flowing into the eTracer-BND
and 10 Amps of charge current flowing out to the battery. The eTracer-BND does not
create current! Rest assured that the power into the eTracer-BND is the same as the
power out of the eTracer-BND. Since power is the product of voltage and current
(Volts×Amps), the following is true*:
(1) Power Into the eTracer-BND =Power Out of the eTracer-BND
(2) Volts In×Amps In=Volts Out×Amps Out
* Assuming 100% efficiency. Actually, the losses in wiring and conversion exist.
If the solar module‘s V
mp
is greater than the battery voltage, it follows that the battery
current must be proportionally greater than the solar input current so that input and
output power are balanced. The greater the difference between the maximum power
voltage and battery voltage, the greater the current boost. Current boost can be
substantial in systems where the solar array is of a higher nominal voltage than the
battery.
· An Advantage Over Traditional Controllers
Traditional controllers connect the solar module directly to the battery when recharging.
This requires that the solar module operate in a voltage range that is below the module‘s