Case study: Sky Station, Neudorf, Nelson
“You can't run a heat pump off-grid.” Jon proved otherwise.
Jon has lived off-grid for 15 years, so he knows his stuff. When he built his latest place at Sky Station in Neudorf, Nelson, he wanted to go one step further: run a 5.6kW heat pump entirely off solar and batteries. Several people in the industry told him straight out it couldn't be done.
We ran the numbers. Jon's home is a new build, double glazed, with a compact 60 square metre open plan living area. A small, well insulated space holds its heat, so the heat pump doesn't need to work nearly as hard as people assume. On paper it stacked up. In real life it's done even better than we expected.
The system
Jon chose an Energy Hub Midi: a 5kVA Victron inverter paired with 25kWh of SOK lithium batteries, all pre-wired and tested inside a weatherproof aluminium cabinet that sits outside. Two solar arrays totalling around 5kW feed into two Victron solar charge controllers. It was delivered in July, his electrician connected it to the switchboard, and it was up and running. We monitor and fine tune it remotely, and a wall-mounted tablet in his kitchen shows the system status at a glance.
Jon also swapped his LPG gas hob for an induction cooktop, so he's cut out gas costs completely as well.
What a full winter taught us
The nights the heat pump works hardest are the cold, clear ones. But a cold clear night usually means a sunny morning, so the batteries get a full recharge the next day. The system balances itself out better than you'd think.
The only time Jon needs to keep an eye on things is a run of cloudy days back to back. On a couple of those days he economised a bit, and that just meant not leaving the heat pump running 24/7. That's it.
The result? No generator all winter.
Not once. A warm home, fully off-grid, on a system plenty of people said wouldn't work.
It not only worked, it exceeded my expectations.
I have lived off-grid for the past 15 years and have always used Victron components because they are robust, reliable and come with a solid global warranty. Victron also offer separate hardware components which makes remote diagnostics and servicing quick and easy, which is important if you know little about electronics.
I recently needed a new system for my latest property and I again wanted Victron coupled with reputable lithium batteries. After a lot of research I chose Brendon at Sogen Energy because he was both a Victron dealer and the SOK battery importer. More importantly Sogen offers what no one else does: they install the entire system neatly inside a secure weatherproof aluminium cabinet. They then test it so when it's delivered to you it is literally plug and play. What also appealed to me was the cabinet can be safely located outside, saving both time and the interior space lost by installing everything inside.
I chose a 5kW Victron Midi cabinet system with 25kWh of SOK batteries, which was delivered in July. All my electrician had to do was connect the cabinet to my switchboard and everything was up and running and could be remotely monitored and fine tuned by Brendon. Brendon also custom designed and set up a Samsung Galaxy tablet with the VictronConnect app which is mounted on my kitchen wall, and this always displays the system's operational status on an easy to see screen which my guests think is very cool.
Ambitiously I also hoped to try and run a 5.6kW heat pump using the 25kWh battery bank, and despite some industry doubters Brendon said he thought it would work. It not only worked, it exceeded my expectations. I live in a small, well insulated open plan studio but I was warm and comfortable all winter, and that was with the heat pump running every night too. I also switched to an induction cooktop to eliminate the LPG costs of using a gas hob, and this works really well too.
I'm very happy with my latest system and the Victron components work seamlessly with the reputable SOK batteries. Couple that hardware with Brendon's decades of experience in electronics and you can be assured you are getting something very few others have: great product options and genuine hands on expertise and support.
Jon, Sky Station, Neudorf, Nelson
If you've been told your off-grid plans aren't possible, get the numbers run properly first. Get in touch.
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