Solar Intensity Meter

This is one of the most fascinating analogue instruments I have seen.

Simple, elegant, rugged and functional, this instrument is called the Campbell Stokes Sunshine Recorder. It was invented in the mid 1800s, and the design remains more or less the same today. At a time when just about everything works on electronic sensors and wireless transmission, this equipment contains just three components - a metal base, a glass ball and a piece of paper. 

Once properly aligned to the correct latitude-longitude, the instrument simply catches the suns rays throughout the day and burns a line through the blue-paper (the "sunshine-card"), placed at its base. The stronger the sunlight, the broader and deeper the burn!

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REFERENCES 

https://en.wikipedia.org/wiki/Campbell%E2%80%93Stokes_recorder

Solar: Upstream and Downstream

Amazing things are happening in India's renewable energy market - especially solar power.

Yesterday , it was reported that at an auction of a 250 MW capacity plant at Bhadla (Rajasthan), South Africa’s Phelan Energy Group and Avaada Power bid INR 2.62 (USD 0.04) per kilowatt-hour (kWh) to win contracts to build capacities of 50MW and 100MW, respectively, at Adani Renewable Energy Park Rajasthan Ltd. This is a new record low. The bidding wars seem to have now reached a point where experts are wondering if it is commercially viable to produce produce power at these rates.

If the unit price is surprising, so is the sheer scale of the new 'solar farms' that are coming up. The current world record the world's largest solar project in a single location is now held by Adani's 648-megawatt Kamuthi plant (near Marurai, Tamil Nadu), which went online in September, 2016. The second largest solar plant, the Topaz Solar Farm in California, has a capacity of 550 megawatts.

For a country that located in the tropics, India has a huge potential for switching over to solar energy. Consider these facts -

• The solar  radiation incident over India is equal to 4–7 kWh per square meter per day with an annual radiation ranging from 1200–2300 kWh per square meter. 
• It has an average of 250–300 clear sunny days and  2300–3200 hours  of sun shine per  year. 
• India's electricity needs can be met on a total land area of 3000 km2  which  is  equal  to  0.1%  of  total  land  in  the country 
• Currently  India is  generating  4.59%  of solar energy  of  total  produced  renewable  energy  installed capacity in India

Over the past few years, thanks to a concerted push by the government, India has quadrupled its solar-generation capacity from 2,650 MW on 26 May 2014 to 12,289 MW in 10 March 2017.  Yet, behind all these impressive numbers, fact remains that present and future growth is completely hinged on the import of equipment from China. In 2015-16, the value of imported solar cells and modules tripled to $2.34 billion, with China accounting for 83 per cent ( $1.9 billion).

Despite having a dedicated Ministry for New and Renewable Energy (MNRE) for the past 15 years, why is it that India has not been able to it own supply chains? Why is it that Indian manufacturers have no access to domestic upstream raw material supplies of poly-silicon and wafers?

According to a KPMG report (2015), India has not been able to create economies of scale in solar manufacturing, mainly due to insufficient government support - loans, tax holidays, subsidized utility services, easy access to land and technology support.

Is that a rather simplistic view?


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REFERENCES & LINKS

* (2017) Wire - Why Increasing India’s Solar Energy Capacity Won’t Work -- https://thewire.in/116842/solar-energy-india-capacity/

* (2017) Mint - http://www.livemint.com/Industry/MKI7QvOhpRoBAtw3d4PM5K/South-African-firm-bid-takes-solar-power-tariffs-to-new-low.html

* (2017) - Solar panel imports - https://www.zauba.com/import-solar-panel-hs-code.html -- HSCode - 39209919

* (2017) - http://indianexpress.com/article/business/economy/pm-modi-calls-for-all-solar-power-city-model-stresses-job-creation-4648770/

* (2016-Dec) -- http://indianexpress.com/article/india/indias-87-per-cent-solar-cell-imports-from-china-in-april-september-piyush-goyal-4417312/

* (2016) - BL - Import of solar panels triples in 2015-16 -  http://www.thehindubusinessline.com/economy/import-of-solar-panels-triples-in-201516/article8788743.ece

* (2016) - Adani's Kamuthi Solar Power Project - http://www.ecowatch.com/india-solar-market-2118202661.html

* (2016) - India's solar energy push to generate 1 mn green jobs -- http://www.business-standard.com/content/b2b-manufacturing-industry/india-s-solar-energy-push-to-generate-1-mn-green-jobs-116021500523_1.html
- Report by Natural Resources Defense Council (NRDC) and the Council on Energy, Environment and Water (CEEW) -- ‘Filling the skill gap in India’s clean energy market: Solar energy focus’
- The country will need new skilled workforce & training to achieve its ambitious national target to add 100 gigawatts (GW) of installed solar energy by 2022
- one million new engineers, technicians, solar installers, maintenance workers and performance data monitors
- International Solar Alliance (ISA) -  alliance of more than 120 solar-rich countries aims to facilitate widespread deployment of solar power and supporting knowledge exchange on manufacturing and skills.

* (2015) - DTE - WTO rules against India in Domestic Contents Reqirements for the Solar Industry -- http://www.downtoearth.org.in/news/wto-rules-against-india-s-domestic-content-requirements-in-solar-power-50977
- Indian manufacturing capacity of solar cells and modules is limited to 1,386 MW and 2,756 MW respectively. The Mission's target at the time of the complaint stood at 10,000 MW to be achieved in the period from 2013 to 2017.
- Since the solar target has been revised to 100,000 MW or 100 GW by the Modi government, the target now stands at 29,000 MW.

* (2015) - Research Paper - Potential of Solar Energy in India - https://www.researchgate.net/publication/306034848_Potential_of_Solar_Energy_in_India_A_Review
-  The solar  radiation incident over India is equal to 4–7 kWh per square meter per day with an annual radiation ranging from 1200–2300 kWh per square meter.
- It has an average of 250–300 clear sunny days and  2300–3200 hours  of sun shine per  year.
- India's electricity needs can be met on a total land area of 3000 km2  which  is  equal  to  0.1%  of  total  land  in  the country

Potential of Solar Energy in India
- Currently  India is  generating  4.59%  of solar energy  of  total  produced  renewable  energy  installed capacity in India

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* India Solar Resource Maps - http://mnre.gov.in/sec/solar-assmnt.htm
* NREL - National Renewable Energy Lab - http://www.nrel.gov/international/ra_india.html

* International Solar Alliance (ISA) - http://intsolaralliance.org/

* (2016) Yes Bank - Compendium of Global Success Stories in Solar - http://intsolaralliance.org/docs/CompendiumofGlobalSuccessStoriesinSolarEnergy.pdf

* (2015) - KPMG Solar Manufacturing Report - http://www.energetica-india.net/download.php?seccion=articles&archivo=3Eksv7L8BosildPLOdK84G1zZk6Ew1co6BVp8hm0LThwxw9APH9HOx8.pdf

* Wiki - List of solar manufacturing companies - https://en.wikipedia.org/wiki/List_of_photovoltaics_companies

Zero Energy Building

A rather unusual looking building came up in South Delhi a couple of years ago. Amidst other, conventional government buildings in the Jor Bagh area, "Paryavaran Bhavan", the new office of the Ministry of Environment and Forests (MoEF), looks as though its wearing a graduation cap.

A  closer look reveals that the cap is actually an elongated, cantilevered roof which holds a vast array of solar panels. This seven-storied tower covering 32,000 sq.m, and accommodating over 600 government officials is India's first "Net Zero Energy" building. The solar panels generate 930 KWp of power, which is more than enough to meet its annual energy requirements of 1.4 million Units at 9KWh. The building actually generates a surplus of about 70,000 KWh which diverted back into the grid.

According to MoEF, this "Multi-storied Building with 100% Onsite Power Generation", is the first of its kind in India. Apart from those solar panels on the roof, it uses a Chilled Beam System of air conditioning which saves more than 50% in energy consumption. The building incorporates a Geothermal Heat Exchange System as well as seven "Machine Room Gearless Lifts (OTIS) that converts braking energy into electrical energy (regenerative brakes, as in automobiles). The building also has its own plants for water and sewage treatment -- in other words, it neither takes any energy from outside, neither does it dump its waste into the city's drains.

Who were the people behind such a pioneering effort? How did the usually hidebound CPWD, with its record of making dreadful looking public buildings actually undertake this leap of faith and technical flourish?

Unfortunately, there seems to be nothing in the 'public domain' that either chronicles, or celebrates this achievement. The CPWD website (accessed 19 April 2017), does have a  button titled "Click Here for Old PPTs", and this does lead to a list of projects that includes this building. None of the URLs work.

Dig a little deeper at other websites (ICFILD, CSE) and you would find that CPWD did indeed lack in-house expertise for such a project. So the government did the the next best thing - it employed competent consulting agencies for each of the specialized aspects of this project. CPWD then brought in its formidable project management skills and completed this building in just two years' time (Jan. 2011-Oct 2013). Among them was Deependra Prashad's DPAP -  the architecture firm that designed this building.

Is this new approach going to be the new norm in public works? Have we finally graduated to better designed public buildings?


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LINKS & REFERENCES

- MOEF Pamphlet - "A New Benchmark in Sustainable Built Habitat"
- CPWD - PPT - Technical Presentation - http://cpwd.gov.in/CPWDNationBuilding/InaugurationPM25.02.2014/Technical_Presentation.ppt
- Case Study (2014) - http://icfild.org/ire2014/seminar/06_deependra_prasad/spa_ipb_deependra.pdf
- Ramachandran, Smriti Kak (2012) - A Green Revolution in Letter and Spirit - http://www.thehindu.com/news/cities/Delhi/a-green-revolution-in-letter-and-in-spirit/article3820306.ece

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VITAL STATS

Capacity of power generation: 930 KWp
Annual energy requirement and generation: 14 Lakh Units 9KWh
Total area covered by solar panels: 4600 sqm
Building plinth area: 32,000 sqm
Structure: G + 7 floors + 3 basements
Solar Panels: Covering 4600 sqm, monocrystalline with 20% efficiency
Amenities: 440 TR HVAC Air Conditioning; Lifts, Fire Alarm System; DG Sets, UPS, IBMS and CCTV Systems; Fully automatic robotic car parking for 330 cars
Architecture, Planning and Execution: Central Public Works Department (CPWD)
Cost: INR 209 Cr. (USD 32.4 million)

Battery Blues

Our stairwell now has a functional solar light that gets triggered with an automatic twilight switch. Yet, the circuit is not really working as I had expected, and I wonder if the problem lies in the solar panel, the charger, or the battery.

Initially the panels had been rigged to a Sealed Maintenance Free (SMF) battery I got from a friend. It was an Exide 26Ah SMF - compact,and relatively lightweight at ~8 kg. The trouble was that even after getting charged by the 60Wa panel in over five hours of clear sunshine, it would not get the ~12W LED panel to run for more than a few hours.

Perhaps this was because the battery had got discharged after lying unused for more than a year. So, based on an online tutorial, I pried open the sealed valves and poured in a bit of distilled water in all its compartments. This did not seem to work either, with the LEDs going blank after about 3-4 hours every evening.

At this stage I purchased a dedicated solar battery from Okaya. This one was a 40Ah tubular battery, weighing more than 15kg. Big, heavy and designed for the outdoors.  In theory it was expected to hold about 480 Wh of juice (40Ah x 12V). It worked just fine the first night. The lights switched on automatically at dusk (5:30PM) and stayed on until daylight turned the twilight switch off (6:30AM). In effect, during this 13-hour duration it should have used up about 156Wh (12W x 13 hrs).

Again, in theory, there should have been about 324 Wh remaining in the battery (480 Wh - 156 Wh). Yet, within two days, the battery turned out to be completely discharged.

Okaya was a bit tardy when it came to servicing warranties but a service engineer turned up and checked the battery. It was showing an output of 12.31V on the multimeter, but after checking all the six compartmetns with a hydrometer, he declared that the  battery had indeed got discharged. Aparantly, the density (specific gravity) of the electrolyte had dropped way below 1.265 for a fully charged battery.

The next day, he came with a charger (16V), plugged the battery to the mains and said that it would get recharged in the nex 24 hours. All the caps were left oepend during charging because he expected it to bubble during the charging period.

Now the solar lighting system seems to be working perfectly fine, even though I continue to be nervous about the voltage drops. A dusk-to-dawn operations brings down the battery voltage to 11.86V, and it looks like the 60Wa panel is not really doing its job of topping up the battery even when there is bright sunshine for ~5 hours every day.

So, finally, the key questions that need answers are -

• How does one measure the juice remaining in a battery? 
• If the 60Wa panel is not doing its job, should I get an additional panel?
• Is the LED panel consuming more than the 12W, as claimed by the vendor?

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8 Dec,, 2016 - Update:

So far, my understanding of solar systems has been guided by the WWW, shopkeepers and technicians who had many years of installing systems. Yesterday, I finally met somebody who was not only a hands-on expert but also one of the pioneers in the solar ecosystem in India -- Yeshwant Thakur, ED of Surya Kiran Technologies Inc.

One look at a pic of my hastily assembled unit and he pronounced that I had been wasting my time and money. The "Tata BP" solar panels were cheap imitations that could never deliver 60Wa; the charge controller was a rip-off, and, I did not have to buy a separate twilight switch in the first place!

A dusk-to-dawn sensor, built into the CC was all that was needed. It would simply sense the incoming current from the panels to decide that the ambient light was not enough, and to turn on the light circuit.

Also, if the battery needed 10 "chappatis" of sunlight, it the panels had not been giving it even the bare minimum of two (6Amps), even while the LED lights were making it work overtime. So, in the absence of sufficient current coming in from the sunlight, the battery had gone back into deep-discharge mode. The only solution was to get the battery charged on the mains, once gain, and to get a new panel that feeds in at least 100Wa (6A) to the battery.

Wish I had met YT before seeking advise from the quacks at Bhagirath Palace!

23 Feb., 2017 - Update:

By stumbling, I am learning to walk.

For the third time in two months my Okaya battery got discharged for mysterious reasons. Earlier, it was the amperage of the solar panels that was causing the discharge. The vendor had sold me a 20Wa panel claiming that it was an "original" 60Wa panel from TataBP. I had got this one replaced with a 100Wa panel from a Noida-based company.

Since I had been travelling during Dec-Jan., I was able to fix the new panel about a month after I had got the battery charged on the mains. When the battery went kaput after three days, I had to get it charged on the mains again. During the charging process (20+ hours) the acid levels had dipped to half, so I had topped it up with distilled water after charging before fitting it back to the solar unit. So now I had a 100Wa panel, a 40Ah battery, a solar charge controller (Phocos) and a twilight switch (Electrocine).

Now I thought I could forget about the lighting system for the next one year, at least. Yet, the charge lasted for less than a week. What had gone wrong? Winter was over, so there had been sharp sunshine for more than 6 hours every day (100Wa * 6A = 600Wh), the battery was getting charged on a 6A current, so it should have had about 500Wh of juice to spare (40Ah*12V = 480Wh), an the load was less than 150Wh/night (10W * 12hrs = 120Wh). So there was no reason for the system to fail.

The Okaya engineer - Ranjit -  visited today to do some serious trouble shooting. He loaded the battery to the home inverter and added load (5 lights, 2 fans) until the voltage dipped to less than 10.5V. Then he tested each compartment and found that all 6 were working just fine. The only possibilites were -  the solar panel was not able to charge the battery, or the SCC was cutting-off the charging process. Neither seemed logical.

Ranjit then had a brainwave. The mistake had been to top-up the battery water after it had been charged on the mains for two days. This had brought down the specific gravity, and, in turn rendered the whole exercise useless.

Lessons learnt:

• Never all top-up the battery water levels after it has been charged on the mains
• Lead Acid batteries self-discharge fast. So avoid leaving them idle for more than a week.

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REFERENCES & LINKS

* All about lead acid batteries - http://all-about-lead-acid-batteries.capnfatz.com/
* Lead acid battery charging basics - http://www.powerstream.com/SLA.htm
* DV Voltage Drop Calculator - http://photovoltaic-software.com/DC_AC_drop_voltage_energy_losses_calculator.php

* Video - Using a hydrometer to test batteries - https://www.youtube.com/watch?v=SRcOqfL6GqQ
- A lead acid battery cell is fully charged with a specific gravity of 1.265 at 80° F.

* Specific Gravity of LA Battery acid - http://batteryuniversity.com/learn/article/how_to_measure_state_of_charge

* Maintaining SMF batteries - https://dmohankumar.wordpress.com/2012/08/28/how-to-maintain-maintenance-free-battery-tech-focus-5/

Solar Lighting a Dark Stairwell

How much does it take to set up a solar-powered system?

I've been mulling over the installation of a solar-based back-up for a while now. For starters, I wanted to install a self-contained system that automatically lights up our building stairwell. 

The problem is quite straightforward: We stay in an apartment complex that has about 30 towers (4x4 houses each), without a central power back-up. Each apartment has a stairwell that is vulnerable to power outages. At night - especially in winters - it becomes particularly difficult for the children and the elderly to use the staircases.

From whatever little I have gathered so far from the net, a solar-panel based lighting system would require: solar panels, a charge Controller, a deep discharge battery, wiring (4mm), a light-activated switch, and a panel of LED lights.

What I do not know for sure - and this is an ongoing challenge -  are questions for which I am yet to find dependable advise:

• How do I align the panels on the terrace so that they can be installed - and maintained -  easily?
• The most appropriate configuration of panel + controller + battery + LED panels?
• Which is a reliable place from where I can buy the components?

At least in NCR Delhi, it is difficult to find somebody who can guide you. The shopkeepers and aggregators always want to sell you the biggest system possible, whether you need it or not. They are all chasing contracts from big-ticket clients - the railways, public-sector companies, large housing complexes to keep the assembly lines running. Companies like Simpa Networks are building models that resemble telecom service providers. Not for them the one-time pocket-change from individual residences.

Reliability is also an issue. Almost none of the components comes with a performance guarantee. The usual refrain is "electronic cheez hai, kuch bhi ho sakta hai..." (its electronic stuff - anything can go wrong!). Not an encouraging start for people who see this as a long-term investment in clean energy.

Amongst all the people I have met, the most sensible advise came from a marketing executive at Maharshi Vedic Construction. His point was simple - longevity of any equipment depends on how you go about maintaining it. He gave the example of an inverter he has installed at home 17 years ago. According to him, regular vacuum cleaning and greasing is all it takes to make electrical equipment last longer. Clearly he had a point.

Yet, even as a manufacturer of solar panels and controllers, he could not offer a formal performance guarantee for the stuff he was selling. His panels cost INR40/Wa, so a 60Wa panel cost INR2400. The controllers were available only for 10A and 20A with a starting price of INR1100 (note: the 10A model came with a useful USB charging port).

Ultimately, I ended up buying the following stuff from the electonics wholesale market at Bhagirathi Palace, Old Delhi:

- Solar Panel Tata BP - 60Wa (INR 1200)

- Charge Controller - (INR 250)

- LED lights set - 12W (INR 150)

- Twilight Switch - 12V, 6A (INR 368) - from Electrocine Corp, 1801/5-6, Bhagirath Palace

- Copper wire (INR 160 for 10m - Kalinga Gold 4mm copper wire) 

- Battery - 26Ah, 12V

I was about to purchase a new 28Ah battery when a friend offered to pass on an old battery he was going to dump anyway. It has been purchased a year ago but seemed to have got completely discharged due to non-use. It took three about three days for the voltage to climb over 12V.

Apart from the battery glitch, the system seems to be working beautifully. 

Now, only a few questions remain: The battery runs out of juice in just four hours...is the LED panel drawing out more power than 12W? Or is it just an old, deep-discharged SMF battery acting up? How does one measure the W/h remaining in a battery unit?

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Vendor's Contacts:

* DC Twilight Switch - Electrocine Sales Corp, 1801/5-6 Electrical Market, Bhagirati Palace - www.escorp.in 

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LINKS & REFERENCES

* Bijli Bachao - solar panels in India - https://www.bijlibachao.com/solar/solar-panel-cell-cost-price-list-in-india.html

* Understanding Solar Power - an excellent resource that brings "Solar Power to Ordinary People"-- https://livingonsolarpower.wordpress.com/  

* Instructables - Solar charges with day-night switch - http://www.instructables.com/id/Solar-charger-with-day-night-switch-v2/

- 2N3904 NPN Transistor, linked to photo transistor and then using a 100k pot to regulate the sensitivity level.
- Day-night switch - http://www.ebay.in/itm/222242083233?aff_source=Sok-Goog
- INR 292 on EBay

- Solar charge controllers - https://www.batterystuff.com/solar-chargers/charge-controllers/

Solar Powered Vendors

The world is moving on -  coconut vendors are now equipped with solar panels!

Until last year the most popular - and affordable - lighting technology available to the vendors was the "petromax" lamp. Messy, polluting and hard to maintain, these kerosene powered lamps also thrived on a blackmarket for fuel siphoned from the public distribution system. 

Most of the kerosene lamps have now been replaced by LED panels.   A supply chain had evolved around this model in which entrepreneurs had started supplying a complete LED lighting set (light panel + battery + stand), to the street vendors for about ₹20 a night. After 10:00 PM they would go around collecting the lamps, and then getting all the batteries recharged again from an AC outlet.

Now vendors - especially those on the open roads - have progressed to next logical step: charging the batteries using solar panels. 

In this case, the vendor, Kasim, set himself a budget of ₹ 3000 and got a 40Wp panel, a refurbished 12V battery of unknown Ah rating and two LED panels.  He has also paid extra for a charger-box with a 2-pin plug. He got conned on three counts - the seller sold him mobile charger calling it an "inverter", the LED panel cost him ₹200 (available at ₹80), and the worst of all - nobody told him that he needs a Solar Charge Controller (SCC).

Since the SCC controls the fluctuating voltage coming in from the panels, and optimises the charge that a battery can take, Kasim's entire investment s likely to go kaput in a few weeks. 

Kasim's case illustrates the problems most of face while adopting a new technology. He is, of course, an early starter. While most of the other vendors prefer a battery-rental model (₹300/week), he must have worked out that an investment in panels would spare him rental expenses within two months. 

I have tried to help out at bit by checking at Lajpat Rai Market (Old Delhi), and telling him that SCC's are available at ₹ 350 (Shop no. 40, 6Amp, DeepSolar brand). Will he get one installed before it is too late? Or will he continue with his "jugaad" setup, get disillutioned with his panel set and return to the regular mode?

And then, even if he does get himself a SCC, it would be yet another component which comes with no quality assurance, standard ratings or guarantees. 

We have set ourselves ambitous targets for increase in renewable energy capacity. The focus so far seems to be on big companies and on turning vast areas into solar-energy farms. While this is necessary, it is also important to ensure that entrepreners like Kasim have access, not only to solar equipment of reliable quality, but also to information and guidance that helps avoid unnecessary loss of faith in a good source for off-grid, renewable sources of power.

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LINKS & REFERENCES

* https://en.wikipedia.org/wiki/Charge_controller

* Charge Controllers - http://www.freesunpower.com/chargecontrollers.php

* Do I need a Charge Controller? -- http://forum.solar-electric.com/discussion/4518/do-i-need-a-charge-controller

- Battery AH * 2% * Vmp = Panel Wattage

* Do I need a controller? - http://www.mrsolar.com/content/faqs/when-do-I-need-a-charge-controller-and-why.html

* Solar Panel Selection Guide - https://www.bijlibachao.com/solar/india-solar-photovoltaic-pv-panels-selection-guide-understanding-system-quality.html

* MNRE Achievements - http://mnre.gov.in/file-manager/UserFiles/Achievements-of-Power-Coal-and-MNRE-Nov2015-English.pdf 

On Batteries

How do batteries work?

Until today my understanding had been confined to high-school lessons in physics: lead anodes, cathodes, and of charged electrons swimming through sulphuric acid.

Now an enquiry from a friend in Japan is beginning to improve my understanding of an essential device that has become so common place that we not only take it for granted but also miss out on the wide range of batteries in the market now.

Here is an interesting video produced by EngineerGuy - Bill Hammack, University of Illinois:



If you decide to move on from lead acid batteries, the videos take you tthrough other interesting stuff like - the various uses of copper, Qweerty vs. Drovak keyboard layouts, magnetrons in microwaves and the connection between nutmeg and tantalum (!).

Coming back to batteries, they now come in serveral types -  AGM or dry, deep cycle or solar batteries. Unlike automotive batteries which are designed to give out a big burst of energy to start the engine, the AGM/Deep Cycle/Solar batteries are designed to discharge over a long period of time.

This is quite useful when you want to have, say, a streetlight running on solar panels. The panels absorb energy during the day, and keep the roads lit up all night on a single charge.

What if the such energy could be stored to run power-hungry equipment like freezers, microwaves and flatscreens? How would that work?

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USEFUL LINKS

- AGM (Absorbed Glass Mat) battery technology - http://www.solar-electric.com/agm-battery-technology.html/
- Running a microwave on a 12V battery - https://www.youtube.com/watch?v=WeY4qE2afvU
- Winiversal Inverter - https://www.youtube.com/watch?v=1ZhrqvYBqCE

* Power Inverter FAQ - https://www.donrowe.com/power-inverter-faq-a/258.htm
- AMPS X 120 (AC voltage) = WATTS -- This formula yields a close approximation of the continuous load of the appliance
- WATTS X 2 = Starting Load
- Induction motors such as air conditioners, refrigerators, freezers and pumps may have a start up surge of 3 to 7 times the continuous rating.
- The auxiliary battery should be connected to the alternator through an isolator module to prevent the inverter from discharging the engine start battery when the engine is off.