Power to the people

I arrived home after dark on Sunday evening after a weekend away working, and turned on the light. To my shock and horror, nothing happened! “Are my solar batteries flat?”, I wondered. I checked other lights and the fridge – still nothing.

It wasn’t that much of a surprise. It had been raining with stormy winds and complete cloud cover for at least 8 days, and with mostly cloud cover for a couple of days prior. I knew from my weather app that the stormy weather was set to last for another 3 or 4 days. It was my first test, only two weeks into my new tiny house adventure.

I have GridFree's Freedom Kit solar system, comprising 8 solar panels and 4 deep-cycle lithium batteries. An inverter completes the kit. The panels each have a capacity of 385-395 W, generating a maximum of 9 kWh (3 sunlight hours) in Winter and 21 kWh (9 sunlight hours) in Summer. The batteries have a storage capacity of 10.24 kWh each, but only about 80% of that is usable. The inverter and batteries are housed in a special cabinet with access from the back of the tiny house behind the bathroom.

Eight solar panels on the roof capture sunlight

Working out which appliances are power hungry

Door to solar cabinet

I had been very careful with my power: only turning on the lights I needed and thinking about any appliances I used. But I also wanted to live as normally as possible, as an experiment, to see just how long my four deep-cycle lithium batteries would last with “normal” use and no sun.

Solar cabinet housing inverter & lithium batteries

As for appliances, there is the refrigerator, albeit a new and economic model. There are several fans: one to vent the composting toilet, also running continuously; the gas heater fan and console, which I used sparingly due to the unusually warm nights; and the range hood over the stove, with its light and fan, which I use during any cooking that generates steam. In the tiny space I have to balance the need to conserve power against the necessity of keeping condensation to a minimum.

I also used the washing machine during that very wet cloudy week. It’s a new economic model too, but a front loader that heats the water for the wash (I prefer warm-water washes). As I found out later, it uses considerable power for heating; in fact, it’s the most power-hungry appliance. Luckily, it’s the only electrically generated heating. Hot water elsewhere comes from a gas Califont appliance, and all cooking and heating of the tiny house space are via gas. I admit that using a fossil fuel for so many applications is less than ideal, but it’s all part of the balancing act that off-grid living requires.

So how did I fare during my long dark night? I have a good torch and I found a number of candles. Warm blankets and rugs kept me warm. I could heat water on the gas stove if I needed it. My biggest and most immediate power requirement was the fridge. So I visited the landowners in their cosy house, and was able to store the most urgent items in their freezer space.

I also sat with them for a while, discussing generators, because I would need to source one the next day. I had been led to believe by my former landlord that a cheap generator could cost between $100 and $200. The owners had been doing some research of their own, and this is definitely not the case. Generators start from $300 or $400.

The search for a generator

Next day my first task was to contact my solar installer and find out what sort of generator is required to recharge the batteries – the answer being anything that generates 2kW or more. I would also need something I could handle, both to carry and start the motor.

I set off for Rotorua, looking first for hire companies. By chance, after cruising up and down likely streets in the industrial area, I chanced on a small branch of NZ Plant Hire that specialises in generator hire. They happened to have the ideal model for me just back from a previous hire that morning. But at $95/hour! Rather than grab it then and there, I trusted my intuition to do some more research in the big hardware stores.

There I discovered that they don’t hire generators, only sell them. They would normally have a good range available, but in the words of one very helpful sales assistant, “all generators went down to Hawkes Bay after the cyclone”. Cyclone Gabrielle had caused enormous damage over large areas of the upper North Island, but the worst devastation was reserved for the Hawkes Bay region, where thousands were left homeless. Obviously, power services were disrupted, hence the high need for generators.

Inverter display showing generator charging batteries

I returned to the hire place and hired the little generator. I was grateful for the rain to have ceased while I connected it to my inverter and set it going. I needed more help from my wonderfully patient solar expert to ensure the batteries were receiving the charge, and in a few hours I had full power restored. What a relief.

Inverter display showing sunlight charging batteries

I had passed my first test with solar power. I now know approximately how long the batteries last without sun, and what is required when they get low or run out. I also know that I need to do more work to source a generator, although I may have to wait months for a suitable model to become available. I am hopeful that I can last out the winter without further power outages.

For now, although the rain continues intermittently, a high weather pattern is predicted. Seeing the sun shining brightly again will not only be a godsend for my power, but will gladden my heart.

Postscript:

A second power outage occurred about a month later after a prolonged period of rain. On that occasion I went to stay with a friend until the weather cleared.

Months later I now have a generator, bought once new shipments arrived. It’s a 3.5kW model that cost over $800! But more on that story later.