Blue Sky Solar Boost 2000E - Manual (Page 6)

Blue Sky Energy - Solar Boost 2000E
5
OPTIONAL TEMPERATURE COMPENSATION
The charge voltage required by flooded or sealed (AGM or GEL) lead-acid chemistry batteries changes with battery temperature. Temperature
compensation of charge voltage leads to improved battery performance and life, and decreased battery maintenance. Automatic temperature compensation
can be provided using the optional battery temperature sensor p/n 930-0022-20. Most 12 volt lead-acid chemistry batteries require a compensation
characteristic of –30.0 millivolts/
°C (–5.00mV/°C/cell). The graph of Figure 2 shows charge voltage setpoint vs. battery temperature for the factory setting of
14.0 volts @ 80 °F and the compensation characteristic of –30.0 millivolts/°C. As described in the installation section the 2000E can also provide a –20.0
millivolts/ °C compensation characteristic required for 10 cell NiCd batteries and some GEL or AGM lead-acid chemistry batteries.
FACTORY DEFAULT CHARGE VOLTAGE SETPOINT -VS.- BATTERY TEMPERATURE
FIGURE 2
MAXIMUM POWER POINT TRACKING (MPPT)
Patented MPPT technology can extract more power and increase charge current up to 30% or more compared to conventional charge controllers. The
principal operating conditions which affect current boost performance are PV array temperature and battery voltage. At constant solar intensity, available PV
voltage and power increase as PV temperature decreases but it takes an MPPT controller to access this extra power. When PV voltage is sufficiently high in Bulk
for MPPT to operate, a constant power output is delivered to the battery. Since output power is constant a decrease in battery voltage produces a further increase
in charge current. This means that the 2000E provides the greatest charge current increase when you need it most, in cold weather with a discharged battery. In
cool comfortable temperatures most systems see about 10 – 20% increase. Charge current increase can go to zero in hot temperatures, whereas charge current
increase can easily exceed 30% with a discharged battery in near freezing temperatures. For a more complete MPPT description see
www.blueskyenergyinc.com .
INSTALLATION
¾ WARNING: Read, understand and follow the Important Safety Instructions in the beginning of this manual before proceeding.
This unit must be installed and wired in accordance with National Electrical Code, ANSI/NFPA 70. Over current protection must be
provided externally. To reduce the risk of fire, connect to a circuit provided with 30 amp maximum branch-circuit over current
protection in accordance with National Electrical Code, ANSI/NFPA 70. Do not connect a PV array capable of delivering greater
than 20 amps of short circuit current I
SC
at STC. Do not connect BAT– and PV– together external to the unit or improper operation
or damage will result. Terminal block connections accept #20 −10 AWG wire and are to be tightened to 9 in-lb (1 nm). The front
panel serves as a heat sink for power control devices and requires free air circulation for cooling. Do not enclose the front panel
behind a tight fitting door or otherwise substantially restrict air flow. Figure 3 shows generalized connections only and is not intended
to show all wiring, circuit protection and safety requirements for a photovoltaic or DC battery electrical system.
¾ CAUTION: The unit is protected against reverse battery and PV polarity, and swapped PV and battery connections, but will be
damaged by reverse battery to the PV terminals. Transient voltage protection is provided, but steady state voltage in excess of
30VDC on the battery or PV terminals will damage the unit. The unit is not water tight and must be installed in an area free from
rain, snow or excessive moisture. Damage due to improper installation, corrosion, or adjustments or connections other than those
shown in Figure 3 void the limited warranty.
ELECTROSTATIC HANDLING PRECAUTIONS
All electronic circuits may be damaged by static electricity. To minimize the likelihood of electrostatic damage, discharge yourself by touching a water faucet
or other electrical ground prior to handling the 2000E and avoid touching components on the circuit board. The risk of electrostatic damage is highest when relative
humidity is below 40%.