morning and late-in-the-day the sun generates less power than the mid-day sun. Cloudy days produce less power than

sunny days. Geographical areas are rated in average peak sun hours per day based on yearly sun data.

The output of a solar panel is measured in watts. Wattage is calculated by multiplying the voltage by amperage. The formula

for wattage is VOLTS times AMPS = WATTS. For example, a 12 volt 60 watt solar panel measuring 20 X 44 inches has a

rated voltage of 17.1 and a rated 3.5 amperage. V x A = W 17.1 volts times 3.5 amps equals 60 watts. If an average of 6

hours of peak sun per day is available in an area, then this solar panel can produce an average 360 watt hours of power

per day; 60w times 6 hrs = 360 watt-hours.

terminal of one panel to the negative terminal of another. The outer positive and negative terminals will produce voltage the

sum of the two panels, but the amperage remains the same as one panel. So two 12 volt/3.5 amp panels wired in series

produce 24 volts at 3.5 amps. Four of these wired in series produce 48 volts at 3.5 amps. Parallel wiring refers to

connecting positive terminals to positive terminals and negative to negative. The result is that voltage stays the same, but

amperage becomes the sum of the number of panels. So two 12 volt/3.5 amp panels wired in parallel would produce 12

volts at 7 amps. Four panels would produce 12 volts at 14 amps. Series/parallel wiring refers to doing both of the above -

increasing volts and amps to achieve the desired voltage as in 24 or 48 volt systems.

- A charge controller monitors the battery's state-of-charge to ensure that when the battery needs charge-current it gets

it, and also prevents overcharging.

- Connecting a solar panel to a battery without a controller risks damage to the battery. Charge controllers (or charge

regulators) are rated on the amount of amperage they process from a solar array. If a controller is rated at 20 amps it

means that you can connect up to 20 amps of solar panel output current to this one controller.

**PWM****-**The most advanced charge controllers utilize Pulse-Width-Modulation (PWM) - which ensures the most efficient

battery charging and extends the life of the battery.

**MPPT****-**Even more advanced controllers also include Maximum Power Point Tracking (MPPT) which maximizes the

amount of current going into the battery from the solar array by lowering the panel's output voltage, which increases

the charging amps to the battery.

**LVD****-**Many charge controllers also offer Low Voltage Disconnect (LVD) and Battery Temperature Compensation

(BTC) as an optional feature. The LVD feature permits connecting loads to the LVD terminals which are then voltage

sensitive. If the battery voltage drops too far the loads are disconnected - preventing potential damage to both the

battery and the loads. BTC adjusts the charge rate based on the temperature of the battery since batteries are sensitive

to temperature variations above and below about 75 F degrees.

are rated in Amp Hours (ah) - usually at 20 hours and 100 hours. Amp hours refer to the amount of current which can be

supplied by the battery over the period of hours. For example, a 350ah battery could supply 17.5 continuous amps over 20

hours or 35 continuous amps for 10 hours.

Batteries can be wired in series and/or parallel to increase voltage and amp hours. The battery should have sufficient amp

hour capacity to supply needed power during the longest expected period "no sun" or extremely cloudy conditions.

A lead-acid battery should be sized at least 20% above the anticipated power needs. If there is a backup power source,

such as a standby generator along with a battery charger, the battery bank does not have to be sized for worst case

weather conditions. The size of the battery bank required will depend on a number of factors, including: storage capacity,

maximum discharge rate, maximum charge rate, and the minimum temperature at which the batteries will be used.

It is important to understand the relationship between amps and amp-hour requirements of 120 volt AC items versus the

effects on their DC low voltage batteries. For example, if you have a 24 volt nominal system and an inverter powering a

load of 3 amps, 120VAC, with a duty cycle of 4 hours per day, your load is 12 amp hours (3A X 4 hrs=12 ah). In order to

determine the true drain on the battery, you divide the nominal battery voltage (24v) into the voltage of the load (120v),

which is 5, and then multiply this by 120vac amp hours (5 x 12 ah). In this example the calculation would equal 60 amp

hours. Another method is to take the total watt-hours of the 120VAC device and divide by nominal system voltage. In this

example, 3 amps x 120 volts x 4 hours = 1440 watt-hours divided by 24 DC volts = 60 amp hours.

- An inverter changes the DC power stored in a battery to 120/240 VAC electricity (or 110/220).
- Most solar power systems generate DC current which is stored in batteries for later use.
- Most lighting, appliances, motors, etc., are designed to use AC power, so it takes an inverter to switch from DC to 120

VAC, 60 Hz). - In an inverter, direct current (DC) is switched back and forth to produce alternating current (AC). Then it is transformed,

filtered, stepped to get it to an acceptable output waveform. The more processing, the cleaner and quieter the output,

but the lower the efficiency of the conversion. The goal is to produce a waveform that works for all loads without

sacrificing power in the conversion process.

**M****odified sine wave inverters**make the conversion from DC to AC very efficiently. They are relatively inexpensive,

and work for most household appliances. Most 120VAC devices use modified sine wave. Exceptions are devices

such as laser printers which use triacs and/or silicon controlled rectifiers are damaged when provided mod-sine wave

power. Motors and power supplies usually run warmer and less efficiently on mod-sine wave power. Some devices,

like fans, amplifiers, and cheap fluorescent lights, give off an audible buzz on modified sine wave power.

**Sine wave inverters**can virtually operate anything. Your utility company provides sine wave power, so a sine wave

inverter is equal to or even better than utility supplied power. A sine wave inverter can "clean up" utility or generator

supplied power because of its internal processing.

- Inverters are made with various internal features and many permit external equipment interface. Common internal

features are**internal battery****chargers**which can rapidly charge batteries when an AC source such as a generator

or utility power is connected to the inverter's INPUT terminals.

- Auto-transfer switching is also a common internal feature which enables switching from either one AC source to

another and/or from utility power to inverter power for designated loads.

- Battery temperature compensation, internal relays to control loads, automatic remote generator starting/stopping and

many other programmable features are available.

- Most inverters produce 120VAC, but can be equipped with a step-up
**transformer**to produce 120/240VAC. Some

inverters can be series or parallel "stacked-interfaced" to produce 120/240VAC or to increase the available amperage.

percent efficient, and other factors. These efficiency losses vary from component to component, and from system to

system and can be as high as 25 percent.

at which work is done or energy is consumed. The formula for average power is acquired by dividing work by the time

needed to perform work: P = W/t. Power has units of newton-meters per second or joules per second or watts.

site within the power plant, consisting of a central mover like a turbine that is then pushed by water or steam to run a

system of generators.

are in use. Some appliances take a lot of energy to operate, so it will result in more use of power. A kilowatt-hour is the

electrical energy consumed in one hour at the constant rate of one kilowatt. The average household uses 8,900 kilowatt-

hours of electricity each year.

light bulb draws at any particular moment is of course 100W.

electricity is used (watts) and the length of time it is used (hours). For example, a 100-watt light bulb, which constantly

draws 100 watts, uses 100 watt-hours of electricity in one hour.

(kW) equals 1,000 watts, and one kilowatt-hour (kWh) is one hour of using electricity at a rate of 1,000 watts. Energy-

efficient refrigerators use about 1.4 kilowatt-hours per day, and about 500 kilowatt-hours per year.

megawatt (MW) = 1,000 kilowatts = 1,000,000 watts.

billion watts.

AC ApplianceHours of Daily Usage X Appliance Watts = Daily Watt Hours Used

5) to determine your Rough Battery Estimate.

Total Daily Watt Hrs. Used x days of autonomy >>>5,634

discharge in normal operation and an additional 50% in emergency situations.) Safe Battery Size in Watt Hrs.

Formula:Rough Battery Estimate x 2 >>>11,268

48 volts DC) Safe Battery Size in Amp Hrs. Formula: Safe Battery Size in Watt Hours / System Voltage >>>470

roundup to the next inverter wattage size. Properly sized inverter wattage Formula: Add Total Appliance Watts + 25% >>>2,

500

- Solar Panel - Collects energy from the sun to provide power to electrical devices.
- Energy Storage - To store energy for later use, Batteries are used as Energy Storage Devices.
- Charge Controller - A Charge Controller controls the charge to the battery and prevents overcharging.
- Inverter - An Inverter is needed if you want to switch stored DC power to AC power used for most household devices.

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- PV panels from 5 to 500 Watts
- Flexible solar panels
- Rigid solar panels
- Polycrystalline cells
- Monocrystalline cells
- Thin film panels

- AE Solar
- Evergreen Solar
- Grace Solar
- Iowa Thin Film
- Powerfilm
- Sharp
- Solartech
- Solarworld
- Sunlinq
- Suntech
- Sunwize
- Unisolar

- Solar PV Panels
- Solar Generators
- Charge Controllers
- Inverters
- Batteries
- Installation Kits
- Mounting Hardware
- Connector Cables
- Portable Solar Chargers
- Complete Solar Power Kits
- Lighting Systems
- Water Heater Systems
- Automotive Vents
- Attic Ventilation

Millennium Planet is a wholesale distributor of an unlimited array of renewable energy components including high quality solar photovoltaic (PV) panels used in

residential and commercial applications, including off-grid, grid-tie systems, as well as portable solar systems and complete do-it-yourself kits. We're partnered with a

growing list of quality manufacturers to ensure that you get the best product for your particular application at the best price. All quality products are CE Certified and

manufactured to ISO 9001 standards. Please call or email for current product and pricing information, discounts and tax incentives.

residential and commercial applications, including off-grid, grid-tie systems, as well as portable solar systems and complete do-it-yourself kits. We're partnered with a

growing list of quality manufacturers to ensure that you get the best product for your particular application at the best price. All quality products are CE Certified and

manufactured to ISO 9001 standards. Please call or email for current product and pricing information, discounts and tax incentives.

electricity using solar power are:

- Solar panels charge the battery,
- The charge controller ensures proper charging of battery,
- The battery provides DC power to the inverter,
- The inverter converts DC power to household AC current.