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Welcome to the Solar Power Forum

Hello,

I wanted to kick this forum off by asking a question, why are you interested in solar photovoltaics?

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Permalink Reply by Martin Herzfeld on September 25, 2009 at 6:46pm: Briefly, specifically, for instance if ~205 watt modules STC, http://www.gogreensolar.com/products/sanyo-hit-205-watt-solar-panel...

Maximum Power Voltage (Vpm): 56.7 Volts
Maximum Power Current (Ipm): 3.62 Amps

Power = Voltage * Current => 56.7 V * 3.62 A = > ~ 205 watts at 25 degrees C, 1kW/m2, ....

Two modules series:

Power = Voltage * Current => ((56.7 V) * 2) * 3.62 A = > ~ 410 watts at 25 degrees C, 1kW/m2, ....

Two modules parallel:

Power = Voltage * Current => (56.7 V) * (2 * 3.62 A) = > ~ 410 watts at 25 degrees C, 1kW/m2, ....

Why series instead of parallel? Simple answer - because of power loss. On the DC side, Power Loss = I(mp) 2 * Resistance. The National Electrical Code Chapter 9, Table 8 provides resistance distance.

IF you notice, since, the power loss is a factor of current, if the current increases, the power loss increases. Therefore, simply 410 Watts not equal to 410 Watts. If the calculations were for voltage drop, you find the voltage drop would increase as a factor of current. As a result, the best practices, would be to increase the number of modules in the photovoltaics source circuit based on the V(oc) and NEC 690.7 with above the V(min) of the inverter and MPPT at a percentage to factor Light Induced Degradation (LID) over time, hot climates, other other factors.

Also the inverter on the AC side would be near the point of connection with regards to the voltage drop a ~1%. Although the voltage drop on the DC side may be 2-3%, would be for administrative purposes, and the method is to determine the power loss for the balance of systems (BOS), where BOS + Array = System.

From a financial perspective, integrators maximize panels. From a customer perspective, would suggest consider maximizing modules. Also the value of energy may be based on azimuth and the solar noon and may be based on time or usage.

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Permalink Reply by Deep Patel on January 17, 2010 at 10:07pm: does your product have a modified sine wave or pure sine wave inverter?; ▶ Reply to This

Permalink Reply by sylvia wilson on April 2, 2010 at 8:40pm: It is a possibility that it will save people a lot of money over time when they invest in solar energy and help the environment.; ▶ Reply to This

Permalink Reply by Jonathan Friedman on April 3, 2010 at 3:29pm: I just found you today, while looking for information on bypass diodes in my solar panels. I had installed a 2 kW photovoltaic system, which was turned on in mid-January. Here in Arecibo, PR it is producing about 8-10 kWh per day typically, which is about 2/3 of our power usage. I have been keeping a blog on my experience at http://jonathansolarhome.blogspot.com. I have long been interested in solar PV, and when we built our house 6 years ago, I put in a solar water heater right away. When Puerto Rico instituted its tax credit program 2 years ago, I started to work on it in earnest, and we had it installed just in time to enjoy a 50% reduction in costs because of the credit. I hope this will reduce our carbon footprint and be part of our small contribution to preserving the environment for future generations.; ▶ Reply to This

Permalink Reply by John Smith Cullum on June 25, 2010 at 10:06am: Deriving energy from the sun offers numerous environmental benefits. It is an extremely clean energy source, and few other power-generating technologies have as little environmental impact as photovoltaics. As it quietly generates electricity from light, PV produces no air pollution or hazardous waste. Moreover, it does not require liquid or gaseous fuels to be transported or combusted. Also, because its energy source, sunlight, is free and abundant, PV systems can offer virtually guaranteed access to electric power.

John Cullum
Professional Installer
Borrego Solar: Commercial Solar Energy Company; ▶ Reply to This

Permalink Reply by Deep Patel on June 28, 2010 at 5:37pm: that is true. how about the manufacturing process of a solar panel. is it a "dirty" process?; ▶ Reply to This