John & Carol Sousa Phone: 541.867.4948 Mobile: 541.961.3572 [email protected]

John & Carol Sousa Phone: 541.867.4948 Mobile: 541.961.3572 [email protected]

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advertisers index

ABS Alaskan Inc., www.absak.com 133

Abundant Renewable Energy, www.abundantre.com 28

AEE Solar, www.aeesolar.com 31

AEE/REC Solar, www.recgroup.com/usa 5

Aerostar Inc., www.aerostarwind.com 114

Affordable Solar Group, www.affordable-solar.com 26/27

AltE, www.altestore.com 63

Alternate Energy Technologies LLC, www.eaglesunsystem.com 62

Alternative Power & Machine, www.apmhydro.com 129

Ampair, www.ampair.com 110

AnemErgonics LCC, www.anemergonics.com 129

Apex Solar, www.apxsolar.com 133

Apollo Solar, www.apollosolar.com 2

Apricus Solar Co. Ltd., www.apricus.com 64

APRS World LLC, www.winddatalogger.com 122

ART TEC, www.arttec.net 121

BackHome Magazine, www.backhomemagazine.com 115

Backwoods Solar Electric Systems, www.backwoodssolar.com 76

Bernt Lorentz GMBH & Co. KG, www.lorentzpumps.com 17

Blue Sky Energy Inc., www.blueskyenergyinc.com 91

Bogart Engineering, www.bogartengineering.com 109

Brand Electronics, www.brandelectronics.com 128

Butler Sun Solutions, www.butlersunsolutions.com 128

BZ Products, www.bzproducts.net 122

C Crane Co., www.ccrane.com 114

CMS Magnetics, www.cmsmagnetics.com 114

Conergy Inc., www.conergy.us 3

DC Power Systems Inc., www.dcpower-systems.com 37

Direct Power and Water Corp., www.power-fab.com 89

Electric Auto Association, www.eaaev.org 129

Electro Automotive, www.electroauto.com 118

Electron Connection, www.electronconnection.com 90

Energy Conservation Services, www.ecs-solar.com 109

Energy Systems & Design, www.microhydropower.com 123

Energy Wise Solutions, www.energywisesolutions.net 129

Enphase Energy, www.enphaseenergy.com 39

Evergreen Solar, www.evergreensolar.com BC

Exeltech, www.exeltech.com 101

Free Fuel Forever, www.freefuelforever.com 129

Fronius USA LLC, www.fronius-usa.com 10/11

Fullriver Battery USA, www.fullriverdcbattery.com 95

groSolar, www.grosolar.com 65, 100

Harris Hydro, 707-986-7771 122

Heliodyne Inc., www.heliodyne.com 19

Home Power Inc., www.homepower.com/20years 134

Hydrocap Corp., 305-696-2504 128

Hydroscreen Co. LLC, www.hydroscreen.com 114

Innovative Solar Inc., www.innovativesolar.com 119

Jan Watercraft Products, www.janwp.com 133

Kaco Solar Inc., www.kacosolar.com 4

LEDS Growing Green, www.ledsgrowinggreen.com 133

Liberty Enterprises Inc., www.iloveebikes.com 129

Magnum Energy, www.magnumenergy.com 47

Maverick Solar, www.mavericksolar.com 119

Micro Circuit Labs, www.microcircuitlabs.com 121

Midnite Solar Inc., www.midnitesolar.com 50

Midwest Renewable Energy Assoc., www.the-mrea.org 111

MK Battery, www.mkbattery.com 30

Morningstar Corp., www.morningstarcorp.com 29

N. Am. Board of Cert. Energy Practitioners, www.nabcep.org 123,127

Northern Arizona Wind & Sun, www.solar-electric.com 125

Northwest Energy Storage, www.solaronebatteries.com 101

Offline Independent Energy Systems, www.psnw.com/~ofln 115

OutBack Power Systems, www.outbackpower.com 8/9

Phocos USA, www.phocos.com 127

PixyJack Press, www.pixyjackpress.com 125

Power Battery Co. Inc., www.powerbattery.com 46

RAE Storage Battery Co., 860-828-6007 133

Rheem Water Heaters, www.solahart.com 38

RightHand Engineering, www.righthandeng.com 133

Samlex America Inc., www.samlexsolar.com 91

San Juan College, www.sanjuancollege.edu/reng 125

Simmons Natural Bodycare, www.simmonsnaturals.com 133

SMA America Inc., www.sma-america.com 21

Solar Converters Inc., www.solarconverters.com 111

Solar Depot Inc., www.solardepot.com 12/13

Solar Energy International, www.solarenergy.org 71

Solar Pathfinder, www.solarpathfinder.com 127

SolarWorld California, www.solarworld-usa.com 51

Solectria Renewables, www.solren.com 77

Solmetric Corp., www.solmetric.com 122

Southwest Windpower, www.windenergy.com 15

Stiebel Eltron Inc., www.stiebel-eltron-usa.com 57

Sun Frost, www.sunfrost.com 123

Sun Pumps Inc., www.sunpumps.com 115

Sun Spot Solar, www.sssolar.com 128

SunDanzer, www.sundanzer.com 119

Suntech Power Holdings Co. Ltd, www.suntech-power.com 22

SunWize Technologies, www.sunwize.com IFC

Surrette Battery Company Ltd, www.rollsbattery.com IBC

SustainableChoice.net, www.sustainablechoice.net 128

Swiss Solar, www.swiss-solar.net 95

Thermomax, www.solarthermal.com 124

Trina Solar Ltd., www.trinasolar.com 25

Trojan Battery Co., www.trojanbattery.com 23

U.S. Battery, www.usbattery.com 110

UniRac Inc., www.unirac.com 77

Wattsun, www.wattsun.com 127

WindMax Energy, www.magnet4less.com 108

Windstream Power LLC, www.windstreampower.com 129

Xantrex, www.xantrex.com 1

Zephyr Industries Inc., www.zephyrvent.com 133

Zomeworks Corp., www.zomeworks.com 123

For easy online access to advertisers, visit www.homepower.com/resources/advertisers

Back IPa

Back IPa

PV Array Temperature Impact Calculations

PV Temperature Performance

Temperature affects a PV module's voltage, and must be considered when matching a PV array to either a maximum power-point tracking (MPPT) charge controller (for battery-based PV systems), or a batteryless grid-tied inverter.

Charge controllers and inverters have a DC-input operating range that the array must stay within. If the DC input dips below the minimum voltage, the system may go off-line and no power will be produced. If the DC input maximum voltage is exceeded, damage to the charge controller or inverter can occur, or potential production will be lost.

To calculate an array's voltage range, you must first determine the record low and the average high temperatures for the site. These temperatures for a weather station near you can be found by appending your zip code to the end of this Web address: www.weather.com/weather/climatology/monthly/.

Using that data, you can find the highest open-circuit voltage (Voc) and lowest maximum power voltage (Vmp) for a given array—for example, a single-string, 10-module, grid-tied array installed in Paonia, Colorado (zip code 81428).

Here, the record low is -31°F (-35°C) and the highest average high temperature is 90°F (32°C). Checking the back of the modules, each is specified at:

Temperature coefficient of Voc: -160 mV/°C or -0.160 V/°C

Cold = High Voltage

The maximum array Voc considers that the site's coldest temperature is usually reached close to dawn. With little or no sun exposure, the PV cells are assumed to be at ambient air temperature.

Online Temperature Data

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