Economic Review Damankan : May 2017

Tuesday, May 9, 2017

WHAT IS A SOLAR CHARGE CONTROLLER AND WHY DO I NEED ONE?

A charge controller, or charge regulator is basically a voltage and/or current regulator to keep batteries from overcharging. It regulates the voltage and current coming from the solar panels going to the battery. Most "12 volt" panels put out about 16 to 20 volts, so if there is no regulation the batteries will be damaged from overcharging. Most batteries need around 14 to 14.5 volts to get fully charged. The best charge controller i can offer you is RENOGY 20 AMP MPPT SOLAR CHARGE CONTROLLER

DO I ALWAYS NEED A CHARGE CONTROLLER?

Not always, but usually. Generally, there is no need for a charge controller with the small maintenance, or trickle charge panels, such as the 1 to 5 watt panels. A rough rule is that if the panel puts out about 2 watts or less for each 50 battery amp-hours, then you don't need one.

For example, a standard flooded golf car battery is around 210 amp-hours. So to keep up a series pair of them (12 volts) just for maintenance or storage, you would want a panel that is around 4.2 watts. The popular 5 watt panels are close enough, and will not need a controller. If you are maintaining AGM deep cycle batteries, such as the Concorde Sun Xtender then you can use a smaller 2 to 2 watt panel.
WHY 12 VOLT PANELS ARE 17 VOLTS

The obvious question then comes up - "why aren't panels just made to put out 12 volts". The reason is that if you do that, the panels will provide power only when cool, under perfect conditions, and full sun. This is not something you can count on in most places. The panels need to provide some extra voltage so that when the sun is low in the sky, or you have heavy haze, cloud cover, or high temperatures*, you still get some output from the panel. A fully charged "12 volt" battery is around 12.7 volts at rest (around 13.6 to 14.4 under charge), so the panel has to put out at least that much under worst case conditions.
*Contrary to intuition, solar panels work best at cooler temperatures. Roughly, a panel rated at 100 watts at room temperature will be an 83 watt panel at 110 degrees.

The charge controller regulates this 16 to 20 volts output of the panel down to what the battery needs at the time. This voltage will vary from about 10.5 to 14.6, depending on the state of charge of the battery, the type of battery, in what mode the controller is in, and temperature. (see complete info on battery voltages in our battery section).
USING HIGH VOLTAGE (GRID TIE) PANELS WITH BATTERIES
Nearly all PV panels rated over 140 watts are NOT standard 12 volt panels, and cannot (or at least should not) be used with standard charge controllers. Voltages on grid tie panels varies quite a bit, usually from 21 to 60 volts or so. Some are standard 24 volt panels, but most are not.
What happens when you use a standard controller

Standard (that is, all but the MPPT types), will often work with high voltage panels if the maximum input voltage of the charge controller is not exceeded. However, you will lose a lot of power - from 20 to 60% of what your panel is rated at. Charge controls take the output of the panels and feed current to the battery until the battery is fully charged, usually around 13.6 to 14.4 volts. A panel can only put out so many amps, so while the voltage is reduced from say, 33 volts to 13.6 volts, the amps from the panel cannot go higher than the rated amps - so with a 175 watt panel rated at 23 volts/7.6 amps, you will only get 7.6 amps @ 12 volts or so into the battery. Ohms Law tells us that watts is volts x amps, so your 175 watt panel will only put about 90 watts into the battery.
Using an MPPT controller with high voltage panels

The only way to get full power out of high voltage grid tie solar panels is to use an MPPT controller. See the link above for detailed into on MPPT charge controls. Since most MPPT controls can take up to 150 volts DC (some can go higher, up to 600 VDC) on the solar panel input side, you can often series two or more of the high voltage panels to reduce wire losses, or to use smaller wire. For example, with the 175 watt panel mentioned above, 2 of them in series would give you 46 volts at 7.6 amps into the MPPT controller, but the controller would convert that down to about 29 amps at 12 volts

Six Ways to Create Economic Growth

Promote economic growth through innovation - Just as we saw at the 2013 International CES®, innovation and start-ups fuel our economic growth. They are the ultimate job creators who start with ingenious ideas, take risks and create value for the American consumer. Our nation has been built by encouraging entrepreneurship and innovation. Especially in our current economic downturn, it is crucial that we pursue national policies that promote innovation to ensure that there will be enough prosperity to carry on into the next generation.
Strategic immigration reform - As other countries aggressively reach out to skilled immigrants, we have made it more difficult for foreign entrepreneurs to come to and stay in America. Our refusal to let more highly skilled immigrants into America is costing jobs, delaying economic recovery and harming our international leadership in innovation and entrepreneurship. We should grant automatic green cards to STEM graduate students from U.S. universities and pass the Dream Act to allow law-abiding people brought to the U.S. as children to become citizens. The Startup Act is another common sense measure that would create green cards for immigrants who register through a business and meet employment and investment benchmarks in the U.S. We should work to expand and remove the country caps on H1-B visas and fix the EB-5 program, which would give visas to immigrants who invest at least $500,000 and create at least 10 jobs.
End the war on drugs We have spent billions, incarcerated millions and made the situation worse. Why not follow Spain’s lead and treat the addicted and decriminalize and tax marijuana? Evidence shows that legalization does not add to drug use and can generate large revenues. Economists have estimated that legalizing marijuana would save the government $7.7 billion per year on enforcement. Of this savings, $5.3 billion would go to state and local governments, while $2.4 billion would be accrued to the federal government. Two states who voted recently to legalize marijuana, Colorado and Washington, are expected to bring in $550 million in revenue combined.
Require unemployed workers to volunteer - We encourage unemployment by rewarding the unemployed. All research shows the longer the unemployment payments the longer the jobless stay jobless. By shortening the duration of unemployment insurance and requiring those receiving checks to volunteer at a non-profit, both parties can benefit. By contributing to society, they can gain skills, contacts and references that will help them be successful in the next job they attain and in turn, we would see fewer people claiming unemployment.
Cut health care costs:Let’s be honest about our ability to afford Social Security and Medicare and means test based on wealth – including assets. We simply can’t afford to pay for these any more. We can stop incentivizing doctors to use the most expensive drugs. Many doctors are paid a percentage of the cost of the drugs they use. If we ban drug company rebates to doctors and pay by the injection rather than the cost of the drugs, then we will cut Medicare spending. We must also allow Americans to buy prescription drugs from overseas. Thanks to the deal that the White House cut with drug companies, we have a wall around our nation for imported drugs and every nation in the world pays a lot less for the same drugs. We will save billions if we can pay what any other country pays.
Remove unnecessary and unclear lawsIndustries often set international standards for testing and measurement, but the Department of Energy (DoE), flush with cash, seems intent on hiring consultants to create new and redundant test procedures. For example, there are industry standards for measuring energy usage in TVs and cable set-top boxes. Current DoE rulemakings waste taxpayer money reinventing the wheel. In addition, these new laws can also be ambiguous, making it harder for businesses to know if they are violating the laws. Government prosecutors have made their reputation at the agencies like the National Labor Relations Board (NLRB), the Federal Trade Commission (FTC) and the Fish and Wildlife Service by threatening legal action against great companies like Boeing, Gibson and Google. Unfair laws like these waste government resources and hurt the competitiveness of U.S. companies.