Why do solar street lights fail in Ghana ?Why are our streets so dark? Why are we not seeing working solar street lights in our streets today?

The answer is simple: some stand-alone solar street lights cause more problems than they solve. In some cases they don’t solve any problems at all.In Ghana a lot of streetlights are installed during  the election year ,streets are kept lit constantly and then all of a sudden the lights go out and never come on again.In recent times regular streetlights have been replaced with stand alone solar streetlights and some of them are quite fancy.

Smart Solar Street Light installation in Antigua and Barbuda

The real question is still whether this technology is economically feasible right now or whether we should wait for technology to evolve further before we take the inevitable plunge.The question of feasibility has reared its head due to bad decisions on the implementation of inadequate solar
components combined with “quick fix” solutions versus sustainable, long-term solutions.
The solar street light is a prime example of this. How many solar street lights have you seen that are not in working order? If you haven’t seen any solar street lights at all, it may be that the local municipality has not been convinced of the feasibility of these systems because so many systems have failed to date.
The solar street light is mostly sold as an LED street light with a battery box and a solar panel mounted on top of a 6 – 9 m pole. This is known as a “stand-alone” solar street light. The theory is that the solar panel will charge the battery during the day and, at night, the light will use the power stored in the battery to provide light.This idea should be considered a match made in heaven and a solution to many problems: streets lights use a lot of electricity and eliminating even only half of this consumption would lighten the strain burden on the grid. LED has a much longer life expectancy, so maintenance costs on the lights should
be minimal. So why do we not see this exciting development in our streets today? The answer lies with a combination of quality and longevity and with an understanding of the products.

Victron Energy’s highly efficient, ultra fast MPPT Solar Charge Controllers provide more efficiency in solar street lighting

The lighting units use quality components. The solar panels are 24% efficient (about as good as you can get commercially) and the LED lights are among the best at 160 lumens per watt (lm/W). The more lm/W a lamp produces the more efficient it is.A traditional incandescent light is around 15 lm/W, an energy-saving fluorescent bulb is around 60 lm/W. Easy then to see the attraction of solar power for free and lamps that are over 10 times as efficient as old fashioned bulbs – all which nicely meets companies requirements for improvements in sustainability and efficiency.

EnGoPlanet Inc ,a New York based company chose to use Victron Energy’s highly efficient, ultra fast MPPT Solar Charge Controllers, plus Victron batteries together with lighting options such as:

  • Wireless internet connection for remote control and management.
  • Smart Cameras.
  • Sensors for collecting various environmental data.
  • Mobile phone charging stations.

Their Smart Solar Street Lights are used in the Kuwait project, where 140 units have been installed. Petar Mirovic, CEO of EnGoPlanet tells me that the success of the project has interested other oil companies too, such as Saudi Aramco who are considering an installation of over 1,000 units in the coming months.

Well – that all sounds to me like a recipe for success!


Apparently the economics for backup power alone just aren’t that attractive.

Tesla has quietly removed all references to its 10-kilowatt-hour residential battery from the Powerwall website, as well as the company’s press kit. The company’s smaller battery designed for daily cycling is all that remains.

The change was initially made without explanation, which prompted industry insiders to speculate. Today, a Tesla representative confirmed the 10-kilowatt-hour option has been discontinued.

“We have seen enormous interest in the Daily Powerwall worldwide,” according to an emailed statement to GTM. “The Daily Powerwall supports daily use applications like solar self-consumption plus backup power applications, and can offer backup simply by modifying the way it is installed in a home. Due to the interest, we have decided to focus entirely on building and deploying the 7-kilowatt-hour Daily Powerwall at this time.”

The 10-kilowatt-hour option was marketed as a backup power supply capable of 500 cycles, at a price to installers of $3,500. Tesla was angling to sell the battery to consumers that want peace of mind in the event the grid goes down, like during another Superstorm Sandy. The problem is that the economics for a lithium-ion backup battery just aren’t that attractive.

Even at Tesla’s low wholesale price, a 500-cycle battery just doesn’t pencil out against the alternatives, especially once the inverter and other system costs are included. State-of-the-art backup generators from companies like Generac and Cummins sell for $5,000 or less. These companies also offer financing, which removes any advantage Tesla might claim with that tactic, as GTM’s Jeff St. John pointed out last spring.

“Even some of the deep cycling lead acid batteries offer 1,000 cycles and cost less than half of the $3,500 price tag for Tesla Powerwall,” said Ravi Manghani, senior energy storage analyst at GTM Research. “For pure backup applications only providing 500 cycles, lead acid batteries or gensets are way more economical.”In Ghana  good  quality lead acid batteries such as the AGM telecom batteries retail at $219/Kw/hr and can be purchased at nocheski Solar (Victron Energy partner ) in the port city of  Tema. These AGM batteries have 1800 cycles at a D.O.D of 30% or 750 cycles at a D.O.D of 50%

 AGM telecom battery by victron energy

AGM telecom battery by victron energy

In California, batteries can benefit from the state’s Self-Generation Incentive Program (SGIP). But California regulators have indicated that battery systems need to be able to cycle five times a week in order to be eligible, which would exclude Tesla’s bigger battery.

“In current discussions on SGIP program overhaul, it is very likely that stronger performance requirements may get added, which will make a 10-kilowatt-hour/500 cycles product outright ineligible (if cycled only once a week), or last only 2 years (if cycled every weekday for about 500 cycles over 2 years),” said Manghani. “In short, the market’s expectation is that for a $3,500 price tag, the product needs to have more than just 500 cycles (i.e., only backup capabilities).”

Backup power alone simply doesn’t have as strong a case as using a battery for self-consumption. That said, the opportunities for self-consumption are still few and far between.

A GTM Research analysis for residential storage, purely for time-of-use shifting or self-consumption. found that the economics only pan out in certain conditions. In Hawaii, for instance, the economics of solar-plus-storage under the state’s new self supply tariff looks only slightly more attractive than solar alone under the grid supply option.

“So it comes down to the question of customer adoption of a relatively new technology for only slightly improved economics,” said Manghani. “This doesn’t mean residential customers are not deploying energy storage,” but he noted that these were the early adopters.

Tesla appears to be focusing its efforts on first movers and the markets where storage for energy arbitrage and self-consumption makes economic sense.

While the 10-kilowatt-hour option has been removed, the Powerwall website continues to offer specifications for Tesla’s 6.4-kilowatt-hour battery designed for daily cycling applications, such as load shifting. The battery is warrantied for 10 years, or roughly 5,000 cycles, with a 100 percent depth of discharge. The wholesale price to installers is $3,000.

The smaller battery is often marketed as 7 kilowatt-hours, which would appear to have a price of $429 per kilowatt-hour. In realty, it’s a 6.4 kilowatt-hour battery at a price of $469 per kilowatt-hour.

A bigger, cheaper or more integrated battery product could soon be added to Tesla’s lineup. In January, CEO Elon Musk announced a new Powerwall option will be released this summer.

“We’ve got the Tesla Powerwall and Powerpack, which we have a lot of trials underway right now around the world. We’ve seen very good results,” said Musk during a talk to Tesla car owners in Paris, The Verge reports. “We’ll be coming out with version two of the Powerwall probably around July, August this year, which will see [a] further step-change in capabilities.”

At this point, it’s unclear what the “step-change” will be.

 

 


Why your Lead Acid Battery is all Swollen Up

Working in the solar Energy industry in Ghana, I often come across several batteries that are swollen up .These mostly lead acid batteries have often than not, been purchased at very high prices not too long ago. On this particular occasion our team was conducting a survey at a prospects home in Tema when I noticed that all of her eight 100Ah batteries were swollen.

Typically a 100Ah battery will cost between $200-$300 depending on quality .In addition to this, most suppliers in Ghana give little or no warranty even though some global brands like Victron Energy give up to two year warranty on their batteries .This article aims to reveal to the public why lead acid batteries swell-up and how to avoid the problem.

Sealed lead acid batteries – both AGM and gelled electrolyte can swell up and expand sometimes. This happens due to the construction of lead acid batteries which is referred to as “recombinant”. They are constructed in such a way to allow absorption of gasses released during the chemical process inside the battery.

The positive and negative plates are placed very close together with only the thickness of the divider separating them. They are tightly secured in the cell cavity resulting in very little extra space inside the battery. When the cell plates expand, it exerts pressure on the inside walls of the battery. This situation can cause the battery case to swell resulting in possible splits and cracks at various points of the battery.

Why Do Battery Cell Plates Expand?

The cell plates most often expand due to overcharging of the battery. The battery may also expand due to shorting of the terminals of the battery. Both these situations results in heating up of the cell plates inside the battery. The lead of the cell plates has a high expansion rate when heated.

The outcome is that the battery experiences extreme pressure inside that swells up and deforms it. The swelling-up of the battery may also cause great damage to the internal components and parts.

Why your Lead Acid Battery is all Swollen Up ,How to Avoid Swelling Up of the Battery?

Overcharging or short-circuiting of the battery is the only reason for swelling up of the lead acid battery. The problem is not inherent in the battery itself. In order to avoid swelling up of the battery you need to tackle the underlying cause of the problem.

You need to follow proper instructions in charging the battery. The culprit may be that you are using a wrong charger when charging the battery. If the charger is providing too much current, this may be the cause for battery swelling up. For instance, if you used 24V charger to charge a 12V battery it will most probably result in overcharging of the battery.

Whatever the reason for overcharging of the device, the end result is the swelling up of the battery. To avoid the prospect of overcharging or short-circuiting of the battery, you need to take the following precautions:

  • Use the right type of charger that is fully compatible with the battery.
  • Ensure proper polarity when connecting the charger to the battery
  • Shield the battery terminals to avoid short-circuiting of the battery
  • Use a charger whose maximum charging capacity is lower than the battery
  • Using a good quality charger
Victron Energy Blue smart charger is a good choice for small battery banks in Ghana

Victron Energy Blue smart charger is a good choice for small battery banks in Ghana

 Battery charging tip: increase battery life with Victron 4-step adaptive charging

Victron developed the adaptive charge curve. The 4-step adaptive charge curve is the result of years of research and testing.

The Victron four-step adaptive charge curve solves the 3 main problems of the 3 step curve:

  • Battery Safe mode

In order to prevent excessive gassing, Victron has invented the ‘Battery Safe Mode’. The battery Safe Mode will limit the rate of voltage increase once the gassing voltage has been reached. Research has shown that this will reduce internal gassing to a safe level.

  • Variable absorption time

Based on the duration of the bulk stage, the charger calculates how long the absorption time should be in order to fully charge the battery. If the bulk time is short, this means the battery was already charged and the resulting absorption time will also be short, whereas a longer bulk time will also result in a longer absorption time.

  • Storage mode

After completion of the absorption period the battery should be fully charged, and the voltage is lowered to the

float or standby level. If no discharge occurs during the next 24 hours, the voltage is reduced even further and the battery goes into storage mode. The lower storage voltage reduces corrosion of the positive plates.

Once every week the charge voltage is increased to the absorption level for a short period to compensate for selfdischarge (Battery Refresh mode

The above tips will help you to protect your battery from swelling up and expanding. Taking precautions will not only protect your battery from being damaged but it will also minimize the threat of fire caused due to overheating of the battery.

Click here for more information on Victron Energy AGM & Gel batteries