Thread: Off the grid power

Re solar hot water.......

We are just about to embark on a fairly serious off grid system at the farm
One of the recomendations was to have an electric HWS, to be used as a dump load.
This would depend on the size of the system and how much electricity you would use during the day.
Once the batteries are topped up in the morning any excess power that is not used ( off grid ) is wasted, so at this point having an array of optional appliances, pumps, HWS and the like means that the power is not wasted.
As an evac HWS will run at 3-4K and you can buy panels at less than a dollar a Watt, you could put an extra 4-5 kW of panels on the roof.

We are also using Lithium batts which are much smaller, can be drained to 80% DOD if required and will take a huge input charge. Can also be put safely inside.
Ours is a 48V, 18.5 kW 3 phase with 1200 Amp/hour Lithium.
Not a cheap exercise but cheaper than bringing in the single phase grid 500 meters to the house. Poles, trany and connection is not cheap anymore.

G'day Barterbuilt, I'm curious about how you would dump your extra power into your hot water system. From what I've been told by various installers of stand alone systems we could only dump straight from the batteries (DC, 12,24 or 48 volt) not from the inverter (ac). that was a while ago so maybe things have changed since the good old days. I'd love to hear your thoughts on the matter or anyone else's thoughts
Cheers
Brendan

Found an interesting site (www.solarhomestead.com) that covers most of the issues I raised previously. The hot water section goes into dumping excess power amongst other things (AC&DC).

Originally Posted by HUON

Berlin, the system equates to 1380 amp hours. I had to ring my friend at Sunreal (Wangaratta) to get the info.
Cheers
Brendan

Huon, is the 1380 amp hour sufficient for your needs given an average house demand?

I just got back from my Tassie block and got some data a the creek for hydro, looks to be a starter but need more winter flow data. I don't think evacuated tubes will be a problem as they perform well in low temp environments, just look at how well they go in Canada and the UK, and I have a great northerly aspect at the right winter angle in the design build.

Shed starting next week now I have the batter cut and supported with rocks (very big ones) so I'm on my way. When at the block I stayed in my dad's motor home which he has some solar panels to charge the batteries and it went very well with plenty of charge going in.

SB

G'day Superbunny, I'll list some of the appliances we run in the house; TV & DVD, computer, washing machine, the gas stove has an electric grill, stereo, two ceiling fans soon to be increased to four, about twenty lights inside the house and nine around the verandah and a tv, almost forgot the fridge.
Now the shed; a bandsaw (20"), a lathe, a drill press, a planer thicknesser (10") tormek sharpener, Dewalt compound cutoff saw and numerous power tools, compressor, pressure washer, bench grinder.
Of course only having two hands I don't use them all at once
I agree with regarding the hotwater tubes.
Cheers

Superbunny, don't forget to post some pics of your progress. Should be of immense interest to similar minded folk.

Haven't read tomorrow's Age yet but the website headlines sound like some interesting reading. A sign of things to come folks, if you don't invest in your own power supply then you need your head read. Don't wait for the parliamentary parrots to catch up.

Seems like they're still struggling. I think the state governments need to regain control of our utilities, and tell the shareholder driven companies to take a long leap off a short pier.

Don't know what it's like in the other states, but here they've nothing left to sell. Everything has been privatized, every cost has gone through the roof, or levied beyond belief.

Things change rather quickly, all you need are some state governments with vision and no vested interests in mining unlike federal billionaire politicians.

Where do we find them?????

OK , point taken (no vested interests might be a bit of a stretch), but I like SA's idea of the big batteries and possibly Vic and QLD following suit. I also like SA's interest in floating solar panels on their water treatment plants or catchments (reduces evaporation as a bonus).

Just been reading the Guardian online, last year according to the article 3.5 million panels were put on rooftops across Australia. That equates to 9,500 panels a day and since 2012 the prices have halved for solar panels. Can't say the same for grid power.
Whoever sold off our utilities should be thrown into jail, after they've been flogged.

Replaced two cells (2 volt batteries) a few days ago, they were about 15 years old. the folk that supplied them said they're selling gel batteries now. While we were getting them into position we started talking about the latest and greatest in battery storage, I mentioned Tesla , I quickly found out that they weren't suited to stand alone systems like ours. It was pointed out that most of the battery technology these days were aimed at returning excess power to the grid (which is not a bad thing).
There is a new lead acid battery, developed by CSIRO, sold by ecolt (suspect spelling), it runs at it's best between 30 and 90 %.