What is MPPT
MPPT
or
Maximum Power Point Tracking
is an algorithm used by better
charge controllers to extract maximum available power from PV modules. The
power produced by PV modules varies widely during the day. Major factors
that affect power output include amount of direct light and cell
temperature. Both Amperage and Voltage are affected.
So what is Maximum Power
Point? The voltage at which PV module produces maximum power is called ‘maximum
power point’ (or peak power voltage). But it's not all about voltage!
On a typical day in the morning as the sun rises the solar panels start
producing voltage and it climbs as the sun does, sometimes right up to Voc
(voltage open circuit) before starting to produce the other half of power (amps)
. It is at this point that all solar charge controller starts charging.
The purpose of MPPT is to
extract the maximum available power from PV modules by adjusting conversion
to provide maximum operational efficiency. Voltage bounces up and down all
day as haze, clouds, sun angle, shade and cell temperature affects PV output.
MPPT technology continuously checks PV output and compares it to battery state
and voltage
and adjusts for the best power conversion to charge the battery by converting to
the optimum voltage to put maximum current into battery. It does this by
internally converting the PV's DC power input to AC power then converting the AC
into the optimum battery charge voltage required by the battery bank at this
point in time.
Now that we're talking
about battery charging, all of the MPPT charge controllers we sell have three
basic levels of charge (bulk, absorb and float) plus some have the ability to equalize the
battery bank when required.
An additional benefit of
the MPPT technology is the ability of many modern charge controllers to accept
much higher voltages than a single solar panel puts out. This allows
higher voltage transmission from the solar panels to the charge controller
minimizing power loss as higher voltage reduces power loss by lowering amperage
by
wire resistance. This is especially useful as solar panels are sometimes a
considerable distance from where the charge controller and batteries are located.
MPPT technology is also
used in Grid Tie and Net-Metering applications but in this case the incoming PV
power can be as high as 600V and output is direct to the electrical grid.
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