As an Industry, Solar professionals should look at popularizing Peltier effect refrigerators and AC/DC washing machines etc. I think the inverter based AC shall slowly have dual power capability to allow working on solar or batteries in the near future.

If one models the demand-supply profile for a home that has the option of deriving electricity from the grid and other captive generation means (diesel genset or inverter/battery setup or solar PV+inverter/battery), it is possible to assess whether there is any true potential for a reasonable financial return on investing in solar PV. It must be borne in mind that the proliferation of residential roof top systems in developed economies was primarily due to incentive mechanisms that guaranteed a return in excess of 10%. Point being that I am yet to come across a study that analyses the implications of investing in a solar PV rooftop system in India. Data such as this is great armor for any consultant.

I recently saw an ad from a leading inverter manufacturer offering solar power inverters so the products are trickling in but capacity is an issue. If we can have a system which can give enough capacity to support even basic electric appliances the scope is good.

Indeed we are in need for good and experienced consultants who provide quality products (solar panels & inverters) and put up the real picture for the consumers. The intentions are there and people are willing to buy a good quality product but over projections by the local marketing managers, leading to high expectations from the consumer end, results inevitably in disappointment and distorting the market.

I need to tell all of you a solar farm with batteries ensure that the power delivered to the inverters is stable DC power. The way these systems are installed is. The solar modules are connected to DC to DC charge controllers. The charge controllers are connected to the battery banks. The battery banks are connected to large 3 phase inverters, the inverters are connected to 3 phase transformers that convert the volts and amps into KVA's. The KVA can go to the substation or transfer station. The transfer stations are grid connected to either the main grid or mini grid or micro grid. The batteries are supplying the inverters stable volts and AMPS. Thus is a cloud or something that would shade the panels the power stays the same because the batteries are the stable source of electric power. Thus there is no power loss due to clouds, fog or rain.

One cannot specifically mention a single path. All of the criteria mentioned come into picture while deciding a choice. Inverter price can never be the first because inverter quality and price are in the opposite side. Inverter installers/consultants have to take initiatives to popularize solar harvesting. They must educate the inverter manufacturers about the positive and negative sides of various options. They must work to create maximum number of grid connected systems. For fruitful results the governments have to promulgate solar policy incorporating grid connection in the policy. Give freedom to consumers the choice for choosing the method -grid connected or independent.

Inverters can exceed 90% efficiency routinely. This is not the big loss term, in context. It's probably better than the raw charge/discharge cycle efficiency of any battery, certainly better than any compression refrigeration system's thermodynamic efficiency. And the solar panel?

I'm designing a 1MW SPV power plant (Utility Scale). I get confused over choosing inverter. I divided 1MW ito 4x250KWp array for which I've selected 4 Central inverters rated @ 250KW nominal power.
Is the selection is correct or should i Consider string inverters for the 1MW SPV plant? For string inverters, I chose 20KWp arrays with 20KW(AC nominal output) Inverters.

By any means, String Inverters are more efficient and down time is minimal due to its distributed generation architecture. Central System over throws String only by economics (of Inverter to Inverters alone). The other costs like Combiners with Communication / Cable (of high size to minimize DC losses from SPV Strings) may be looked into. In the long run, String will be more economical, this is my humble view.

A power inverter can be taken as a crude form of UPS. Obviously the main use of a power inverter is only for powering common electrical appliances like lights and fans during a power failure.
As the name suggests the basic function of a power inverter is to invert an input direct voltage (12VDC) into a much larger magnitude of alternating voltage (generally 110VAC or 220VAC).

Using the latest DC power inverter technology, air conditioner operation is quieter and more economical than conventional AC units. Let's understand what the power inverter technology is and the operating principle of the new air conditioners.

The fixed speed compressor in a standard air conditioner runs at 100% capacity when it is started, but a power inverter unit starts at a low level and then progressively enhances its capacity, depending on the requirement to heat up the room or cool it down. Fixed speed compressors start or stop automatically in order to sustain the desired temperature, but a power inverter unit regulates regulates the capacity of the compressor instead.

If you open the dc isolator on the roof no lethal voltage goes to the inverter to the grid but safety devices are not used when the circuit is operating correctly. Consider a short circuit on the solar panel side of the DC isolator. Even when opening the DC isolator on the roof or at the inverter lethal voltages are being generated and potentially capable of electrocution. Basically, creating an open circuit at the inverter will do nothing. On a damaged array anyone can create an unpredictable alternative current path which may cause electrocution.

Electricians are putting their lives at risk, and many of them are not aware of the issues and problems associated with solar panels. As soon as the sun shines on the array, you’re at risk of electrocution. The trade and the public need to be warned of this problem.

Now that this industry is evolving into a workable, reliable and yes sustainable industry more and more rules and regulations are required to protect the consumers. Grounding of everything someday will be a reality. Solar Panels, Charge controllers, inverters and more equipment will require more and more rules. The power companies don't have the same rules as the solar or wind industry. They don't need permits to install wires on homes. They install their own grounds just at the meter. I am working on a home that was built before there was electric power. This home is DC and AC because of an unstable questionable solution between DC and AC. AX won yet there is a huge power loss from the power plant to the homes. Thomas Edison was aware of this problem so he tried to convince people to have both. Well this old home is one of those homes with both. All LED lighting, TV's, Computers, are DC yet you only work when plugged into AC outlets.

I think your hand drilling machine is using "Universal motor". Such motors work on both AC as well as DC. If that right; If your line voltage is 110 or 120V, take10 panels 12V8Watt panels, connect all panels in series and this will solve your Drilling problem. You can + & - to any P or N wires.
I do not know about your welding m/c. If it is inverter type welding, go for then instead of 8 watts go for 12 watts panels.
If your voltage is 240V then take double number of panel reducing the wattage to half.

PV inverters generally do not provide the amount of instantaneous power required for loads for a sustained amount of time. We only have so much sun and when you look at the power curve for a typical day 95% of the system power is produced between the hours of 10am and 3pm. Most house load profiles do not match this curve as the loads are usually highest in the morning when people are getting ready for work/school and then at the end of the day when everyone gets home. Both of these time periods are outside the solar window so the PV probably won't be able to sustain the power required by the loads.