The National University of Lesotho (NUL)’s Electronics Engineering student, Mahloli Makhetha, has come up with a cool fix for a big problem in some villages in Lesotho —keeping electricity running without killing the batteries too soon! If the battery is doing okay, everything stays on. But once it starts dropping—say, below 70%—the system gives a warning, first to villagers, then to businesses, then to clinics…in a smart way! Mahloli is supervised by Professor Leboli Thamae.

You see, in some rural areas of Lesotho, people get their electricity from something called a mini-grid. We will show you a few of these in the coming weeks. Mini-grids are like a small solar power station for a village.

They use sunlight during the day and stores extra power in batteries for use at night or in cloudy days. But here’s the catch—if those batteries are drained too much, they get damaged and wear out quickly.

And replacing them? It’s Super expensive.

Mahloli steps in right there. She made a small system that watches over the batteries like a guard. When the battery starts to run low, her system gently tells people, “Hey, maybe switch off what you don’t really need.” And if the battery gets even lower, the system takes action—cutting off power to less important users, bit by bit, to protect the battery from getting ruined.

At the heart of this system is something called an Arduino Uno. It’s a tiny computer, about the size of your palm, and it acts as the brain. Mahloli connected it to a circuit that checks how much energy the battery still has. If the battery is doing okay, everything stays on. But once it starts dropping—say, below 70%—the system gives a warning.

First, it flashes an amber (orange) light. That’s like saying, “Heads up! Power’s getting low. Try turning off the TV or the kettle.” If people keep using too much electricity and the battery keeps going down, the system starts turning things off.

Homes go first. If things get worse, businesses are next. But important places like clinics? They’re saved for last. That way, people who really need power—like nurses—can keep working even when energy is running low. When the red light comes on, that’s the final warning: “Power’s almost gone. Get ready!”

So how does the Arduino actually cut power? It uses relays—tiny devices that work like switches. The Arduino tells them what to do, but since it’s not strong enough to move them on its own, Mahloli added transistors to help out. Think of it like the Arduino giving a whisper, and the transistor shouting it loud enough for the relays to hear.

She also added some small parts called flyback diodes. They stop the system from getting hurt when the relays turn off. It’s like wearing a helmet when riding a bike—just in case something goes wrong.

Of course, no creation works perfectly the first time.

Mahloli ran into a small problem while testing her system. She used a knob called a potentiometer to pretend the battery was losing power. But the system got confused and started switching loads off and on too quickly, like it couldn’t make up its mind.

Her fix?

She made the Arduino a bit more patient.

Instead of reacting to every tiny change in the battery voltage, it now takes an average of several readings before making a decision. She also gave it a steady voltage to compare against, so it doesn’t panic over small changes. That made everything run a lot smoother.

And here’s the really cool part—this whole thing only costs about M806 to build! That’s way cheaper than replacing a battery, which can cost thousands. Plus, with Mahloli’s system, batteries can last five years or more, instead of just two or three. That saves a lot of money and keeps the lights on for much longer.

It’s also a great way to help people in villages understand how they’re using electricity. A flashing light is much better than suddenly sitting in the dark (ever heard of horror stories of load shedding from our beloved neighbours?).

It gives people time to adjust and maybe even come together as a community to decide how to share the remaining power.

Mahloli’s project is simple, smart, and super helpful. And it’s just the beginning. She’s already thinking about ways to make it better—maybe sending text messages to warn people about low power, or making a bigger version that can manage more houses.
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