Ten-Hour Power Cuts, and Our House Never Went Dark

It is the end of June 2022, and the power cuts in Sri Lanka are running for about ten hours a day, sometimes more. Through all of it, our house has not gone dark once.

The cuts are one part of a much bigger problem. Sri Lanka is in an economic crisis. The country has run short of the foreign currency it needs to import fuel, and without fuel the power stations can't generate enough electricity. The same shortage has hit the petrol sheds: petrol is rationed, the queues stretch for days, and this week fuel sales were restricted to essential services. A generator doesn't help much when you can't buy petrol to run it.

I want to write down how we got through it, because it didn't start when the cuts started. It started months earlier, with a warning from a friend.

The warning

My friend Udara Logus worked at the Ceylon Electricity Board (CEB). Late last year, Udara told me the power situation was heading somewhere bad and that I should start looking for a generator.

When someone who has worked inside the CEB tells you that, you listen. So I did.

What I put together

I decided not to rely on a generator alone, and built a small backup system for the house:

• Inverter: a 3 kW EA Sun hybrid inverter, ordered from AliExpress.
• Batteries: two 12V 200Ah Eastman solar batteries from Browns, the same people behind Exide batteries here.
• Generator: a Pramac WX 7000, an Italian generator rated at 7 kW.

The generator is honestly overpowered for what we need. Seven kilowatts is far more than our house draws. But it was what was in stock, and when everyone is looking for the same thing, you take what is on the shelf.

I did all the wiring and setup myself and had everything running in early January.

Then the cuts came

Not long after, the power cuts arrived, and they kept getting longer. Then the petrol ran short.

That changed what the system really was. I had bought the generator as the backup, but with petrol rationed, it couldn't be the plan. The batteries had to be. They charge while the grid is up, and they have to carry the house until it comes back.

On paper, two 12V 200Ah batteries hold about 4.8 kWh. That sounds like plenty until you try to stretch it across a ten-hour cut. It only works if you are deliberate about what runs: the essentials stay on, and anything heavy waits until the grid is back.

With careful management of what we used, we lasted the full cycle, every time.

Thank you

I couldn't have done this without help.

Udara Logus, thank you for the warning, and for telling me early enough that I could still act on it.

And thank you to all the people making YouTube videos about inverters, batteries and home wiring. I had never set up anything like this before. Hours of watching other people explain it, step by step, is the reason I could do it myself.

Think about power resilience

If there is one thing I want you to take from this, it is that power resilience is worth thinking about before you need it.

• Don't wait for the crisis. By the time everyone needs a generator or an inverter, the shelves are empty. My oversized generator is proof of that.
• Don't depend on a single fuel. A generator is only as good as the petrol you can buy. In a crisis like this one, the grid and the fuel supply can fail together. Batteries that charge whenever the power is on keep working when the petrol sheds are empty.
• Know your loads. Work out what you actually need to keep running, and size your batteries and inverter for that, not for everything in the house.
• Learn it, but be safe. I'm glad I learned to do this myself, and you can too. But you are working with mains power and large batteries. If you are not confident, get a qualified electrician to do the wiring or check your work.

The cuts aren't over yet, and neither is the crisis. But for now, the lights are on, and I'm grateful for that.