Welcome to Stewart Island & Sails Ashore +64 3 219 1151 tait@sailsashore.co.nz

Sails Ashore is Solar Powered

Click to See our First Post on Stewart Island Energy

Finally !!. though MUCH quicker than we had initially expected as we keep hearing horror stories about supply chain issues.

Shane from Tansley Electrical Arrived a week ago and installed everything over a couple of days. He came back last Tuesday and commissioned the system. So Sails Ashore is now “Off Grid”, although our garage is still on grid. We do have a changeover switch to go back on grid if need be. Shane has some issues with the monitoring systems, and at this stage we are only looking at what’s happening with the battery … either charging or discharging, how much, and state of charge. We can only infer what the panels are producing and what the inverters are supplying to the house. But once he’s consulted the oracle I’m sure he’ll have it sorted.

We’ve had two days on system, and each night the battery has dropped to the mid 70% charge. Both days have been bright sunshine and the battery back to 100% by late morning. Today is cloudy, and at midday we are at 80% charge and charging the battery at around 1000 w per hour over and above our house load. Once we have the two non working displays up and running we’ll have a better idea of what’s happening.



The last of the 16 panels being installed.
A total of 7.04 kw maximum output

We wanted the batteries and electronics well away from the house,
as Lithium Ion Batteries can occasionally go on fire

Lots of little lollies, and a few flashing lights.
We have 2 * 6 kw inverters. The red one is also the Solar Panel regulator.
The big white boxes are the 6 battery modules. each 4kw

We have 24 kw of battery storage, about 140% of our daily winter use.
The 2 larger boxes on the left are inverters, and the rest some switches/circuit breakers and the Internet interface unit.
This allows us to monitor and control from anywhere with internet access.

Domestic Hot Water & Central Heating

We have a diesel fired boiler which produces both domestic and central heating hot water. The cylinder also has a 3kw electric element, which was purely for backup if the boiler failed.

Yesterday at 1500  I switched the boiler off and the electric element on … the battery was at 100% charge … and we ran that for 4 hours until the batter dropped below 100%. Thus saved ourselves around 1 litre of diesel.

At the moment we have to do the switching manually, but again, when the kit arrives this will (I hope) work automatically as soon as the battery state of charge  hits a pre set level. And in time I’m hoping that we can turn the boiler off more or less permanently, at least over the summer.

Load Adjustment.

Our system has 7 kw of PV panels on our roof, and 24 kw of LI battery storage for when the panels aren’t producing. So in bright sunlight from fully discharged  we theoretically should be able to fully charge in 4 hours. Ideally we should adjust our usage to coincide with daylight hours. So laundry during the day, instead of at night, ditto dishwasher, rinse at night, full wash in the morning. We have a very efficient Vestfrost freezer which is supposed to “hold” for up to 56 hours. So maybe run it daylight hours only.


Time only will tell whether this investment will pay. But our research indicates that it will work, especially if we can cut our diesel usage in half.

Currently Electricity is $0.60 per unit, monthly connection is $95 giving us an annual power bill of around $4000.
Add to this diesel for central heating and domestic hot water  @ $5600 pa (total) so we are hopeful we can save around $6000 pa.
(You would be a real optimist if you thought diesel and electricity costs would move in any direction except upwards)

We will retain our grid connection until we are quite certain we can disconnect safely, so I guess next winter will be the real test.

Once we have the final data from the panels and inverters available we will make them available at the following places:-

We have links to all our Solar Power Posts etc on our “Solar Power & Environment” page