A day in the life of an off-grid installer

Last week, a customer near Colac phoned me and wanted to talk about going off-grid I told him I would come down that afternoon. So I printed off one of our Off-Grid info packs and set off for Colac in the Radiant Van.

The customer lived just out of Colac, quite close to another of our Off-grid customers so I was quite familiar with the area.

Within the hour, I was at his property in the middle of a forested area in a small clearing. The house was owner built, of modest size with water tanks, solar water heating, Nth facing main roof and a grid connection

The customer came out to greet me and proceeded to show me calculations of his daily usage which was around 2-3 kwhrs/day – quite modest and that he was intending to install an LP gas stove which would make the usage even lower. We discussed the shading issues from the tall eucs in winter – it is what it is!! A backup generator was also planned.

He was a perfect candidate for going off-grid – already had water tanks, solar hot water, wood stove for winter heating, gas cooking and was planning for gas hot water backup or using the wood heater with a water jacket.

I took some photos and after discussing the implications of going off-grid, I left him with the info pack and promised that I would draw up a quote and send it to him within the next few days.

Back home that evening, I opened my trusty SPS off-grid design program from JP Energy Technology, put in the likely loads that the customer had indicated and totaled up the kwhrs/day. Sure enough, they totaled about 2.5 in summer and around 3 in winter.

From there I went to the Design Area of the program and selected Cape Otway as the closest solar monitoring station. Then I went to the PV Array area and set the brand, size and numbers of solar modules I thought he’d need to cover his winter load.  I chose 3 kwatt which is 12 by 250 watt modules.

I’ve decided to go AC coupling for the solar array – that is the DC energy from the solar panels goes to the ABB solar inverter and gets converted to 240v AC energy which is then fed to the main AC house switchboard. It then directly supplies any house loads that need energy – the fridge, maybe TV, lights, washing machine etc and then any excess goes into the battery. The DC wiring for this arrangement is very simple and makes for a very neat system.  It is our preferred arrangement.

AC coupled system

The SPS design program produces a graph which shows the solar PV output is above the load requirement. This will minimise the need for a backup generator and with panel prices so low these days, it is much cheaper than petrol in the long run.

system performance

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