than battery. If the battery voltage drops
below 13.8 Volts because of heavy loads
or low solar radiation, Naps MaxPower will
change back to MPPT charging mode.
Constant voltage float charging minimises
battery water consumption and corrosion,
thus reducing service requirements and
extending battery life.
Battery type selection
For optimum performance and life, open
(flooded) and sealed (valve-regulated
VRLA) batteries need slightly different
charging voltages. Naps MaxPower can be
used with either type, correct charging is
being selected by setting a switch on the
printed circuit board.
Temperature compensation
If the battery temperature can change over
a wide temperature range, the battery
charging voltage should be adjusted
according to the ambient temperature.
Naps MaxPower has temperature compen-
sation which increases end-of-charge
voltage by approximately 24 mV when
ambient temperature decreases one
degree (e.g. at -5 °C, the end-of-charge
voltage is increased to 14.9 V).
Internal blocking diode
During the night, the internal blocking
diode prevents leakage current from the
battery to the module. It also protects
against damage from high currents from
the battery if the module cables are acci-
dentally shorted.
Low current consumption
Naps MaxPower uses about 6 mA of
battery current, so even if the module is
covered with snow in the winter the battery
drain is less than 5 Ah per month.
Large, robust screw terminals
You can easily connect even two 4mm²
cables to each of Naps MaxPower’s large
high current screw terminals.
Status indicator
The green indicator on the cover of Naps
MaxPower is continuously on during
normal operation. During an over voltage
fault condition, the light will flash continu-
ously. This is usually caused by a blown
battery fuse or corroded or loose battery
connections. Please check them immedi-
ately.
Protection features
The controller has been designed to survive
the most common problems that can occur
during installation or operation.
Input overvoltage
Naps MaxPower’s input is protected
against short over voltage spikes (caused
by lightning) with fast transient voltage
suppressors. To prevent damage to the
suppressors, do not connect continuous
voltages exceeding 45 V to the input.
Input reverse polarity
If the module wires are installed with the
wrong polarity, this will be noticeable by
the fact that the indicator lamp will not light
up and the black heat sink at the top of the
unit will get warm. This will not harm the
unit, and once the polarity has been
corrected it will start to operate normally.
Output (battery connection)
reverse polarity
Naps MaxPower is protected against
reverse battery polarity with a fuse in the
battery lead. If this fuse is blown check the
wiring immediately. The unit must not be