Saturday, December 03, 2016

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?


* All about lead acid batteries -
* Lead acid battery charging basics -
* DV Voltage Drop Calculator -

* Video - Using a hydrometer to test batteries -
- A lead acid battery cell is fully charged with a specific gravity of 1.265 at 80° F.

* Maintaining SMF batteries -

Wednesday, November 23, 2016

A Bridge That Went Too Far

A debate is raging over one of India's first "successful" Public Private Partnership (PPP) projects.

The Delhi-Noida-Direct (DND), an arterial, privately-built road connecting NOIDA to Delhi has been declared toll-free by the courts, and the company in question, ILFS-NTBCL, is trying it best to return to status quo.

By all accounts, the status quo seems like a perfect sweetheart deal where the private company keeps on making handsome returns in perpetuity, at the cost of the public.

The DND story begins in the early 1990s when the country had just initiated major economic reforms and its public infrastructure was in a woeful state. A company formed by retired government bureaucrats, IL&FS, won a contract for building the road-bridge in 1997. The construction was completed ahead of schedule, and the bridge was opened in 2001. Under the contract, the company was to get an assured return of 20% return on investment, over a 30 year period.

What exactly was the investment involved? Now this is where things start getting murky. IL&FS reported that engineering, procurement and construction (EPC) cost was Rs 193 crore. The cost for acquiring the land, facilitated by the Noida administration, was just Rs 11 crore. On to this amount, the company added an a huge  "management fee" of about Rs 200 crores, bringing the total cost to Rs 378 crores.

As if this was not enough, the Total Project Cost (TPC) was calculated ex-post and remained open-ended to include just about anything (with zero-risk to IL&FS). This ensured that the TPC and the toll-rates could be revised upwards with each passing year. It also ensured that the "20% assured return" would always remain unmet, and the total cost spiraled to Rs.5,000 crore in 15 years!

In 2001, the government was wet behind the ears about PPPs. Soon after the DND project was completed it realized that the private developers were leading it by the nose, and came up with a series of measures to ensure fair-play and public accountability in PPP contracts. By 2005, Model Concession Agreement (MCA) were ready for PPP projects, along with samples of other documents like Request for Qualification (RfQ) and Request for Proposal (RfP).

So what happens to the contract that was signed between IL&FS and the government (UP & Delhi)? The company, quite naturally, continues to claim that it has the legal right to do as it pleases.

Fortunately this issue has come to a head with the filing of a Public Interest Litigation (PIL). The Allahabad High Court noted that NTBCL had “recovered all reasonable returns” on its investment, and was no longer entitled to collect toll. The company filed an appeal to the Supreme Court which tossed it aside with a note of sarcasm - "You have only ten kms of highway", the bench said, "and you claim that you have made a road to the moon"!

A follow-up study is now analyzing the company records for the profits it has made so far. It would be interesting to know exactly how the ex-bureaucrats went laughing all the way to the bank.

* Puri, Pradeep (2016) Article by the ex-IAS officer who joined IL&FS -
"Making the DND Flyway Toll Free can Ring Death Knell for Private Investment in India"

* Rejoinder - Mohanty, Nalini (23Nov16) - "Why the DND is a Virtual Sellout at Public Expense" -

* Mint (2Nov2016) -

* DNA (28Oct2016) -
* Indian Express (28Oct2016) -

* Singh, Abhinav Prakash (10Apr2013) -- Delhi-Noida Toll Bridge- Loot in the name of Public-Private Partnerships (An excellent primer!) --

* Chandran, Rahul (2007, Mint) -

* Qunit (16Oct16) --
- the court noted that “the Concessionaire, according to their own financial statements, has recovered Rs 810.18 crore (approx) from toll income from the date of commencement of the project till 31.03.2014 and after deduction of operation and maintenance expenses and corporate income tax, the surplus was Rs 578.80 crore.”

Monday, November 14, 2016

LED Brightness

What makes some LEDs brighter - and more durable - than the others?

The Maglite Solitaire has a tiny LED that uses a 1.5V AAA cell to produce 47 lumens. On the other hand, the standard bulb distributed by electric utility companies like UPs PVVNL uses 7W from the grid to produce 700 lumens of light.

In terms of lumens per watt (lm/W), the stardard measure of lighting efficiency, the Maglite stands at 33.5 lm/W and the UP bulb at 100 lm/W. Both are small change compared to recent innovations from companies like Philips which have produced lighting units that can produce more than 200 lm/W!

However, as anybody who has used a Chinese LED bulb/panel would attest, it takes a lot more than just lighting efficiency to measure durability and useful life of an LED bulb.

Considering the fact that the super efficient LEDs from companies like Nichia-Japan and Philips are beyond the reach of regular users, is there any global standard that sets the benchmark for LEDs that strike the best balance between lighting efficacy and affordability?


- Top 10 LED manufacturers -
- Maglite -
- Philips - now more than 200 lm/w -
- Super high luminous efficacy -
- Energy storage in batteries -

De-monetization in India

At 8 PM on 8th November 2016, Prime Minister Modi made a surprise announcement: Currency notes for INR 500 and INR 1000 were being declared invalid with almost immediate effect. 

The stated objective was to put an end to black money, terror funding and rampant forgery.

Six days later, I continue to be impressed with the secrecy and swiftness with which this decision was implemented. At the same time, it is clear that was not thought through. For one, it is astounding that the RBI would design and print currency notes that does not fit into standard ATM machines. 

The shock and awe tactics does seem to be having some effect on people who had got accustomed to hoarding cash. Consider these examples - 

- Big Bazaar Noida has been selling grocery cash-cards like never before. From 8 Nov., they have been open till midnight, selling cards to ladies lining up with wads of 500/1000 notes. They bought up whatever is available and walk away saying, "Keep the change!"

- At Sector-18 market, on 8 Nov., jewelry shops were open till midnight and the sales personnel hit their six-month target in just four hours!

- The sweepers and cleaners at Tower-3, Unitech South City, Gurgaon, discovered that some resident(s) had dumped poly-bags full of currency notes down the garbage-chute. All the notes had been carefully snipped with scissors so they were of no use to anybody.

- Just about all ATMs in the NCR Delhi region have  serpentine queus of people waiting to use the ATMs. Most of them are young, unemployed boys working on a commission basis - for every INR 4000 withdrawn, they pocket INR 400.


Wednesday, November 09, 2016

Gilded Cocoons

Cocoons are usually drab and unremarkable. It is the multi-colored caterpillars and butterflies that get all the attention.

As if to disprove a point, something unusual was seen today on a milkweed tree (Calotropis procera) in our neighborhood. Tucked away under a calotropis leaf, I came across one of the most beautiful cocoons I have seen so far.

It is designed as though a jeweler was creating a line of cocoons under the category 'Understated Elegance'. At first sight it looks only neat and compact, like a shapely fruit dangling on the leaf. And then you notice something glinting in the winter morning sunlight - a neat line of golden dots that mark a ridge, and then, a few more of these gilded dots scattered as a parting flourish, on the lower side.

A few days down the line, an Oriental Plain Tiger butterfly will emerge from a tiny hole, just above those golden dots, wait for its crumpled wings to dry and unfurl, and then fly away.

The question that dangles in the air is - why would the butterfly want to advertise its presence, at the most vulnerable stage of its life-cycle, by having such an eye-catching design on its cocoon? What could possibly be the evolutionary advantage of having that gilded design on your sleeping bag?


* Butterflies of India - Oriental Plain Tiger -
* Calotropis procera --

Sunday, November 06, 2016

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 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?

Vendor's Contacts:

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




* Bijli Bachao - solar panels in India -

* Understanding Solar Power - an excellent resource that brings "Solar Power to Ordinary People"--  

* Instructables - Solar charges with day-night switch -
- 2N3904 NPN Transistor, linked to photo transistor and then using a 100k pot to regulate the sensitivity level.
- Day-night switch -
- INR 292 on EBay

- Solar charge controllers -

Tuesday, October 25, 2016

Steel Production in Perspective

Staying up-to-date is a quite a challenge these days. There is so much information floating around in the print media, and in cyberspace that its a constant struggle to separate the wheat from the chaff; the signals from the noise.

Take for instance the recent headlines in the Financial Express on global steel production. According to the news report, India has "registered a 6% growth in steel output in Jan-Sept... India remained the only bright spot among major steel-producing nations in the world."

Quite impressive to be the 'only bright spot' -- until you notice a graphic tucked away. Now this tells you that a growth of nearly 6% actually translates in an increase in production from 67 million tonnes to 71 mT. The exalted position of the "third largest producer of steel in the world" looks quite pathetic when you realize that the guy in the fist position has produced 604 mT of steel -- nearly 10x times the Indian production during the same period!

An increase of 4mT gives India an "impressive" 6% growth while just about the same increase (3mT) gives China a growth of "only" 0.4%.

Is there a better case of comparing watermelons and lemons?


- Financial Express (22Oct16) - India registers 6% growth in steel output in Jan-Sept.
- World Steel Association -
- Top Steel Producers (2015) -

Wednesday, October 19, 2016

A Churning of Conventional Wisdom

I like books that yank me out of my comfort zones. The one I am reading right now - Sanjeev Sanyal's "Ocean of Churn" clearly falls into this category.

 Using the latest research evidence available - DNA profiles, population genetics and climate change data -  it punctures many 'historical facts' that have long been accepted as the gospel truth.

While one can find faults with the writing style, with Sanyal's lame attempts at being humorous, the book is certainly worth the hype on social media.

It collates and presents some startling new findings:

* Iron tools were being used in central India 3800 ago, in 1800 BCE  when the Egyptians and Mesopotamians were still in the Bronze Age (2500 - 800 BCE)

* Emperor Ashoka the poster boy for Ahimsa (non-violence) was anything but that. The great Kalinga War (262 BCE) was hardly an inflection point - he had already converted to Buddhism a few years earlier!
Also, the decisive battle may not even have taken place on the banks of the river Daya at Dhauli, but at Yuddha Meruda (Jajpur Distt) and the Kalingan capital city of Tosali (Dharmasala)

* The Sri Lankan Sinhala's have much stronger linkages to ancient Odisha than was known earlier

* In Peninsular India there have been instances of royalty being brought in from South East was a two-way traffic of goods, people and ideas.


* Tiwari, Rakesh () - The origins of iron-working in India: new evidence from the Central Ganga Plain and the Eastern Vindhyas --

* Das, Prafulla (2005): Exploring an Ancient Kingdom -

* Book Review - Mint -

* Book Review - Manu Pillai (Open) - Rim of Life -