Frequently asked questions
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There are a lot of groups doing solar in Africa. Is another Africa solar charity really needed?
Solar4Africa.org started because solar systems in Africa are getting to the richer households but are still not getting to tens of millions of very low income households in rural Africa.
How is Solar4Africa.org different from other Africa solar charities?
We have a laser focus on maximizing the humanitarian benefit per dollar of charity that is donated. For much of our work we can now comfortably generate more than $10 of benefit for every $1 of charity donated.
We think that with a couple more years of work, we can get this up to $100 of benefit for every $1 of charity donated for some projects.
The key to maximizing benefit per donated dollar is maximizing the lifetime of solar systems that are delivered to low-income rural households. This is done by using battery technologies that can last 10 times longer than lithium ion or lead acid batteries which currently dominate the market in Africa.
Why haven't I heard about Lithium Titanate (LTO) batteries before?
Currently they are a specialty, niche battery that garners premium prices that can be ten times higher than the lowest-priced battery on the market. They also have slightly different electrical characteristics than other batteries so some customization has be to done with the battery electronics to make them work efficiently with existing solar equipment.
This means that LTO batteries have almost no visibility on current battery markets and applications.
We solve the problem of high cost by developing custom electronics and system designs that can be assembled in Africa using the raw parts (e.g. industrial quality battery cells). We also develop a very lean and cost efficient assembly and distribution network that can get the Africa-assembled batteries to village households.
With combined cost efficiencies, we can bring the retail cost of LTO batteries in rural Africa down to about $400 per kWh. This is an extremely affordable cost for a battery that can last 10 to 20 years instead of 1 or 2 years like a typical lead-acid battery.
What is a Forever Light?
Our definition of a solar "Forever Light" is a solar light that will last longer than the house it is installed in.
It is possible to do this with a simple, single, cost-effective Lithium Titanate (LTO) battery cell.
A very simple, robust and long-lasting solar lighting system can be made with a low-cost 10Ah LTO pouch cell as follows: First we note that a single LTO battery cell operates at voltages between 1.8V and 2.7V. There are simple, robust voltage converters (used in cell phone power banks) that cost less than a dollar and that can convert voltages in this range to a regulated 5V power supply.
Therefore our 10Ah LTO forever light systems use a small solar panel to charge a single 10Ah LTO battery cell, and then use commodity voltage converters to produce a 5V power supply for LED lights and phone charging. The pouch cell costs less than $6. The solar panel costs less than $5. Wire, voltage converters and LED lights cost about $4, and delivery and installation costs about $5. This creates a basic solar system that provides light and cell phone charging where both the solar panel and the battery can last 10 to 20 years while the system costs only about $20.
We believe that everyone in Africa who currently does not have electricity should have access to such a simple, robust, and long-lasting solar lighting and phone charging system.
The fact that hundreds of millions of Africans currently do not have access to such solar systems is a grave injustice!
Isn't it too expensive to use off-grid solar PV for electric cooking? Why not use a solar thermal cooker?
The vast majority of off-grid solar home systems simply have not been designed to minimize cost of solar electric cooking.
If we specifically focus on minimizing the cost of solar electric cooking, it is possible to make it radically more cost efficient and much less expensive than what is provided in current solar home systems.
In addition, when solar PV is used efficiently and effectively, an off-grid solar PV cooking system can be much more convenient and almost as cost effective as a solar thermal cooking device.
There are four techniques which can be used in combination to radically decrease the cost of off-grid solar electric cooking:
Acquire and distribute low-cost solar PV panels
Efficiently utilize and store solar PV output that otherwise would not be used
Utilize highly efficient cookers
Utilize the long-lasting battery capacity several times per day.
We explain the specific details of how this can be done in a peer-reviewed technical publication that came out in 2021. See:
You can learn more about the global movement for clean cooking with more modern forms of energy at the Modern Energy Cooking Services program of UK Aid at the following website:
Aren't solar pumps expensive? How can low-income village women afford to use them?
The cost of a solar pumping system is approximately proportional to the peak power of the system. What makes solar pumping systems un-affordable to most low-income Africans is the fact that they are usually being sold solar pumping systems that are more powerful than what is needed to meet their most urgent needs.
This means that the majority of very-low-income rural Africans are not able to buy solar pumps that they can afford in their local market. The result is that many resort of manually irrigating their gardens, or wasting money to buy fuel to power a diesel pump. Most low-income women in rural Malawi during the dry season cannot afford fuel and laboriously carry water by hand to water their very small gardens.
How big does a solar pump need to be so that women in rural Malawi no longer need to carry water by hand?
The calculation goes as follows: First we note that the human body can produce about 100 watts of mechanical power. So someone working hard to carry water by hand is exerting about 100 watts of power. Let's say the pump provides peak power that is twice the average power requirement, then you need a pump that is about 200 watts. Now suppose it is partly cloudy sometimes, then you need about 400 watts of peak solar panel power to provide a reliable 200 peak watts of pumping. You need about 600 watts if you want it to work well on a mostly cloudy day.
If we get this pumping system for a cost of about $0.50/watt, then the required solar pumping system costs only about $300. Even better, since you irrigate your garden only about once per week, at least five women can share the solar pumping system, each irrigating their garden about once per week. So providing solar pumps to rural women's groups in rural Malawi costs only $60/woman.
Considerations of basic justice and human dignity demand that every woman who is currently carrying water by hand to water their gardens and vegetable plots, needs to have access to a solar pump.
It costs so little.
Nobody has solar cars. How are you able to distribute solar cars in Africa when nobody is selling them yet?
Actually, if you look on the online international wholesale supply marketplace site Alibaba, there are lots of solar vehicles available now. These wasn't true a year or two ago.
See for example:
But none of these operate with LTO batteries. So we contracted with an electric cargo tricycle manufacturer in China to make a version of their vehicle that has 600 watts of solar panels on the roof and 2 kWh of of LTO battery capacity. We were able to get such a solar vehicle for a factory door price of less than $3,000.
In 2021 and 2022, we conducted pilot tests in rural Malawi that have verified that such a solar vehicle can run all day on sunny days and is much desired by rural villagers.
Small solar cars are now a reality, and for hundreds of millions of people around the world, they provide the possibility of convenient, moderate-speed transportation that costs virtually nothing to operate. All because - at least for now - sunshine is still free.