Selecting Pv Modules; Temperature Compensation; Battery And Pv Wiring - BLUE SKY SOLAR BOOST 2000E Installation And Operation Manual

SELECTING PV MODULES

Voltage, current and power produced by Photovoltaic (PV) modules fluctuate widely with operating conditions. As a result a set of test conditions
referred to as Standard Test Conditions (STC) are used to rate modules in a meaningful manner and accurately predict real world performance. STC
ratings are not maximum or optimal ratings. Conditions can be present where V
Code and our recommendations call for 1.25 derating of both V
Key PV module specifications;
P Maximum power in watts (P
MAX
Voltage with module open circuit (typically ≈20 – 22V for 12V nominal modules)
V
OC
Voltage where module produces Maximum Power (typically ≈17 – 18V for 12V nominal modules)
V
MP
I Current where module produces Maximum Power
MP
I Current with module Short Circuit
SC
The 2000E will provide the best MPPT current boost performance if all PV modules are identical. Dissimilar modules should have V
≈0.5V or better and be of the same basic cell technology so their V
consider using a separate charge controller for each module type to obtain the best MPPT current boost performance. Select PV modules that do not exceed
the maximum ratings shown below, and preferably produce at least 3.5 amps of I
sizing see technical bulletin #100214 at www.blueskyenergyinc.com.
Maximum PV Power @
STC
340W

TEMPERATURE COMPENSATION

For temperature compensation to operate, battery temperature sensor p/n 930-0022-20 must be installed and temperature compensation enabled via dip
switches 3 & 4. The sensor is electrically isolated and may mount to any battery terminal, but battery negative is preferred. Select a temperature compensation
characteristic that most closely matches the battery manufacturers recommendation. Most 12 volt flooded or GEL lead-acid chemistry batteries require the –
30.0 millivolts/°C (–5.00mV/°C/cell) setting. NiCd and many lead-acid chemistry AGM type batteries require the –20.0 millivolts/°C (–3.33mV/°C/cell) setting.
WARNING: Do not attach a sensor or any connections other than Blue Sky Energy battery temperature sensor p/n 930-0022-20
to the temperature sensor terminals. Be certain to observe proper RED/BLK polarity as shown in Figure 3. The 2000E cannot
properly limit and control battery voltage if temperature compensation is enabled with the sensor installed reverse polarity.
Additionally, output current will be disabled if temperature compensation is enabled without the sensor installed.
SWITCH
3
OFF
ON
ON

BATTERY AND PV WIRING

The 2000E panel should be mounted in a dry location that provides easy routing of large size wires to the PV array and battery, and keeps PV/battery wire
length as short as practical. The location should also provide free air circulation around the front of the panel, and if possible, around the rear. Take great care not
to touch or damage circuit board components as this damage is not covered under the limited warranty. Figure 4 provides a 1:1 template for the panel cut-out.
Wiring and connections used with the 2000E can have a significant effect on current boost performance. The 2000E increases charge current by
transforming previously wasted or unharvested power into useable charge current. The effect wiring has on current boost performance is that power wasted
heating wires or connections is power that becomes unavailable to charge the battery. A desirable installation will produce a total system wiring voltage drop of 3%
or less. The lengths shown in Table 2 are one way from the PV modules to the battery with the 2000E located along the path. Wire length can be increased
inversely proportional to actual current. If current was reduced by ½ (to 10 amps), wire lengths could be doubled and still provide the same 3% voltage drop.
and I
OC
= V x I )
MAX MP MP
Maximum PV
Isc @ STC
20A
SWITCH
4
OFF
ON
OFF
NiCd (–2.00mV/°C/cell • 10 cells)
MAXIMUM CONDUCTOR PAIR LENGTH – 3% VOLTAGE DROP
WIRE GAUGE
AWG
12 AWG
10 AWG
8 AWG
6 AWG
4 AWG
and I approach 1.25 times STC ratings which is why National Electrical
OC SC
. Yet in real world conditions I
SC
will tend to track as operating conditions change. If module types are very different
MP
per 100 amp-hours of battery capacity. For more detail on PV module
MP
Recommended range of V
Maximum PV
V @ STC
OC
24.0V
TEMPERATURE COMPENSATION
DISABLED
–30.0 millivolts/°C
Flooded Lead-Acid (–5.00mV/°C/cell • 6 cells)
–20.0 millivolts/°C
♦ AGM Lead-Acid (–3.33mV/°C/cell • 6 cells)
12 VOLT SYSTEM @20AMPS
FEET / METERS
6.4 / 1.9
10.2 / 3.1
16.2 / 4.9
25.7 / 7.8
40.8 / 12.5
TABLE 2
Installation and Operation Manual
is commonly only about 75 – 80% of I
MP
at STC
MP
Nominal 12V PV
16.5 – 18.5V
at STC.
MP
values within
MP
6