Clean Energy

Is your solar backup system promisingly green?

Not every solar backup system buyer is an engineer. It turns out that, they had to be a sharp minded engineer to purchase green solar backup systems (SBS) in Nepal. After five years of my involvement in solar projects, I have come to learn that the whole process of purchasing greener SBS is very complicated and almost not possible in a low trust market like Nepal.

I am also SBS supplier like thousands in whole country .But among thousands; I am one of few engineers involved in this business with a motive to provide technically strong and quality products. I confess, I failed for 99% of my sales to provide high quality product as I promise. You know why? There were few seen things that we could control and more unseen things beyond our control. To the things that we could improve, we did but to the things beyond our mind, hands and budget we learnt a big lesson.
You won’t believe, there’s a horrible situation in the market. I now find wrong with everything, from SBS components to the installation process. Let’s discuss them in detail and start with the module.
Are they really what they say?
Most of the suppliers offer polycrystalline type module in the market. They are rated with certain efficiency and expected to meet minimum 12% efficiency but they barely satisfy the compliance, although it’s always written perfect in sticker back of module. Funny, according to the sticker most of the panel found in Nepal is either made in Germany or Italy, USA, Japan and so goes on the name of developed country whereas the reality is 99% of them are either from China or India. Buyers are innocent and easily cheated with the cheesy sticker. What’s funnier is everybody in the testing authority of GON knows they are not as they are written in sticker yet they get certificate of meeting the compliance.
What’s wrong with hybridizing PV and Grid supply?
There’s a big circus in market for hybridizing Solar PV with grid lines. Buyers choose to hybridize for two reasons, one the system price get low as PV size decreases in hybridizing second people want to get power even in bad weather days. Same reasons apply to supplier proves to be an opportunity to sell more systems in price competitive market. Good supplier offer X price for Y capacity stand alone system whereas, some suppliers offer hybrid systems in X/2 price for and promise capacity same as Y so client are compelled to choose hybrid systems. But the reality is, hybrid systems are not as promised since solar panel current and inverter supply current are not of same nature and same strength. They do not choose to go to battery together. So when there’s grid line, only grid current goes to battery since it’s stronger than other and solar PV current gets chance only if there’s no grid line. With the calculation, the chance of charging with solar PV in hybrid system goes down to only 40% of total production.
Devil on town
Common brand inverter found in Nepalese market is the main culprits behind Solar Backup Systems failure. They are of very low efficiency down to 70% -75 % which ultimately consume major amount of the current in 24 hours produced by solar PV in system smaller than 200 Wp. To simplify, lets say you have installed 200 Wp panel which theoretically (practically they are 30 % less) produce 55 ampere current  in 5 hours of good sunshine whereas your inverter has operational loss of 1.5 ampere (in 1500 VA)  which amount to 36 ampere of loss in 24 hours . Now you have only 19 amperes left for use which is only sufficient to run 40 Watt light for five hours. But while purchasing we expect to run lights , TV and also computers. Forget that.
Do small things make big difference?
Apart from solar module, Battery, Charge Controller and Inverter there are also small accessories like Wires, LEDs, Nut Bolts , Washers associated with the system which are even more vital to keep system effective.
DC wires used in the system must be of copper with good thickness, whereas in our market copper coated iron wires are most popularly supplied which buyers are quite unknown about it. Technically, the resistance of iron wire is about seven times as great as that of copper wire of the same dimension. Thus if a p.d of 10 V causes a current of 2A to flow through a copper wire it will cause only 2/7 A to flow through iron wire. That means, we are losing 5/7 amount of current using copper coated iron wire.
 Stainless steel alloys and other metal clamps, lugs, washers, nuts and bolts have also been known to cause problems with electrolysis and high resistance. They are the main reason to cause more Sulphation which results deposition of Sulphate on battery terminal where Sulphate resists more current to enter to the battery. It also causes severe corrosion on battery terminal decreases shelf life of battery. So selection of SS battery Nut bolts, Washers and use of lithium grease, petroleum jelly (Vaseline) or commercial battery protector over battery terminal will prevent corrosion.
LEDs, a negative belief have been developed in our market. The LEDs with the enough metal heat sink are not preferred by the Nepalese people, since the first LEDs introduced in our market didn’t have any heat sink and had impressive brightness which gave a understanding to Nepalese people that they are the first one so original one. But, LEDs are adversely affected with high temperature. The junction temperature of LED is a key factor for the life of a LED. In terms of electrical characteristics of LED, junction temperature plays role on pulsed current, flux reduction and color shift.
Only proper installation  guarantees good power output
It doesn’t require an engineering certificate or education degree to sell and install solar backup system in Nepal although they are written to be, to work in subsidy market. But what about the larger market beside subsidy applies. There’s a loot in the urban market. Misinformation about solar PV technology, system design and quality flows everywhere and buyers are confused about on who is right and who is wrong also which one is right and which one wrong.
I am so sad to see some panels are oriented to the west while they had to be towards south. Sometimes they are placed in such a way that they come under shadow of tress, hay tower (Tauwa) or clothes while drying. That will stop panel producing enough energy as rated since the PV cell are arranged in series. I wonder how many of the technicians are aware that battery produces harmful fumes so they shouldn’t be strictly placed in closed room. They require good airflow. Some charge controller has pre-setting at 11V for cutoff while they had to be in 11.6V. Early Voltage cutoff assures long life of battery. But since low cut off Voltage setting allows light even in bad weather while charge is low , supplier choose to cheat for not listening to the “no light” complain.
 What now?
 Here is the checklist to have greener, cleaner Solar PV backup systems.
1.      Are your solar panels oriented towards south at 35 to 40 degrees inclination? Yes.
2.      Are they not affected by any sheds and shadows? No.
3.      Use magnet to identify if they are using really copper wire or iron wire with copper coating. Does it stick to wire? No.
4.      To find out if the panels are not fake, go to their website and see if there really exists such brand in the world? Yes.
5.      Use of battery SS / Copper cable shoe and nut bolt. Yes.
6.       Your backup systems are placed in an open space with enough airflow. Yes.
7.      Do you LEDs have enough metal heat sink? Yes.
8.      Avoid the backup system “culprit” inverter if your need is only light, and if you choose to run other gadgets, do not hesitate to pay more for high efficiency inverters. OK
What would be easier solution  to control solar PV market irregularities?
Simply, government authority could have a call center to entertain queries, help people with proper system design and suggest quality product. People would be assured if they could directly talk to authorized engineer, listen to individual requirement and have a good system designed. It may be quiet complicated to entertain all queries at central level but every district has an energy unit which could more help simplify the solar system installation process and assure good SBS.


Prakash Acharya is an entrepreneur from Nepal, passionately working to substitute fossil fuels with clean energy technologies. He co-founds Mukti Energy, a solar energy company providing a one-stop solution in the sector. He is also a big believer in change so he advocates and works for creating impact in society. His topics of interest spans from sustainability, zero energy, poverty reduction, sociology to smart city. He graduated from Institute of Engineering, Thapathali Campus on Industrial engineering. He is also a former assistant lecturer in IOE, Thapathali . Prakash is a fellow for Social Entrepreneurship Outreach Program 2014, Social Entrepreneurship Forum Sweden.

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