Powering up for the collapse

4 10 2010

I’ve been meaning for ages to talk about our solar power system, but simply never seem to find the time.  But since my last posting on this poor neglected blog, a few things have happened, like me landing a consultancy job selling solar power to people in my area.  Yes… a real job!  Sometimes it feels like I’ve rejoined the Matrix…

Some five years ago, when our house project was barely up (a roof but no doors windows or cladding!) we put 20 US64 amorphous solar panels on the roof (1.28kW) with a German inverter by the name of SunProfi 1500E.  Yes, it’s 1.5kW, and the E stands for Emergency, which means we have battery backup for when the grid fails and we have to endure a blackout.  Or not in our case, the system automatically and instantaneously switches to battery power when this happens.  To be honest, the battery backup is a real indulgence.  First, we started out with a tiny 17Ah battery bank (the more Amp hours the more energy you are storing) which very quickly turned out totally inadequate.  It was soon removed and replaced with a second hand 100Ah set of batteries which cost us the princely sum of $100 and a bottle of rum.  So far they were the better value for money, because they lasted maybe 18 months or more, but they eventually curled their toes up and died.  So, a replacement set made in China and bought on eBay arrived, for a grand total of $1300.  Gel cells…  never again.  They barely lasted long enough to run out of warranty, and the problem with this inverter is that it will not work at all without batteries, and if they are dying, prodigious amounts of solar power is wasted trying to keep them charged up, instead of feeding the grid.

new 500Ah battery bank

Luckily for us, my new boss is one of the few solar people around here who isn’t one of those greedy business people who jumped on the rebates bandwagon to sell grid connected PVs for a quick buck, he actually knows solar, and has been in the business for thirty years….  some people even consider him a guru of sorts!  That’s why I chose him to work for.  And he deals in and knows batteries very well.

Out of the blue, he bought an entire telephone exchange worth of backup batteries for a song.  Not gel cells, and not piddly 100Ah jobs, these were the Rolls Royces of lead acid batteries, 500Ah Yuasa, which, he claims, have been known to last as long as 34 years…..  pretty amazing.  So I bought a set of 24 (2 volts each to make 48V) for barely more than the last set of crappy Chinese batteries.  So far so good.  They are all housed in a brand new little cubby I entirely built out of salvaged materials, looks like it’s always been there!

new PVs

new PVs, old system at the back

One thing I have learned from rejoining this industry after a 15 year period of retirement, everything’s changed.  The incentives to screw panels to one’s roof are now hard to ignore, let alone resist.  So we decided to top up our old system with a totally new one, 2.2kW of, this time, monocrystalline Chinese made PVs with a 2.8kW Chinese inverter.  Yes, China is taking over the world…

I estimate that now we have reduced our consumption to around 3 kWh per day, we will be feeding so much excess energy into the grid during the day that we should make two to two and a half grand a year profit out of the panels…  I now firmly believe that ten years from now, there will be people with panels, and people without power. Or at least people who will not be able to afford the power they currently take for granted.  Only time will tell, but at least we are ready.

UPDATE..

Since first writing this entry, Energex connected us up to our new “smart meter” which automatically works out how much imported energy we need to be charged for, and how much excess we get credited for. After our first month of “smart metering” , said meter is reading -284, 59.  This means we had to buy 59kWh @ 21c = $12.39, and we sold 284kWh @ 52 c = $150.28 for a nett profit of $137.89.

It’s a bit disappointing.  The inverter is playing up, misreading the grid voltage and cutting out constantly, and we’ve had cloudy days after cloudy days.  Still, it’s nice to know we’ll never have another power bill!

It was funny how Energex sent a team of two metering experts all the way from Brisbane (140km) to make sure we were unable to charge the batteries off the grid at 20c, only to sell the energy back to them at a profit for 52C!  As if….  the energy contained in those batteries is worth way more than theirs, and as I told the poor unsuspecting guys, I wouldn’t sell it to them for two buck a unit even if I could!  They drew a wiring diagram of the entire setup, insisted on running the house off the batteries with the panels turned off for more than half an hour, just so they could watch the batteries NOT being recharged when the grid was turned back on.  I expect the exercise would’ve cost Energex at least $1000…  a lot of kWh even at 52c!!

UPDATE 2.

The inverter which was playing up eventually died.  My mistake, I should have followed my intuition and bought a Xantrex instead of supporting the firm I worked for… that’s right, I no longer do.  They no longer sell those inverters either.  It was replaced under warranty, and so far so good seems to work just fine.  How long for is the real question.  After two quarters of this and appalling solar weather, we got our first cheque for just over $500 from the Utility Company.  Hopefully we’ll do better now the inverter is working as designed, and the rain might hopefully go back to “normal”, if Climate Change allows this to actually occur.  At least we will never ever have to worry about any more power bills.

UPDATE 3.

After some two years of faithful service, the backup batteries have been sold because the device that was connected to them started curling its toes after eight years of duty.  See here for details…….


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14 responses

19 10 2010
ulrike

Great blog and interesting post. I am in the process of building and your info about solar sounds is just the way I want to go.

15 12 2010
Dorrian

Great work!

But you should definitively consider some “anti theft system”. Your PVs are easy to deconstruct (simple screws).

There are several kinds of anti theft screws avaiable, and this should not be too expensive.

27 12 2010
John

Don’t have to post this…

on first look at the battery bank–nice. but i think it should not be in contact with the cement blocks (side and back). cold temperature of the earth, and I’ve heard from some oldtimers (perhaps nonsense) but you don’t want to put a battery on the ground/concrete.

nice blog!

27 12 2010
mikestasse

It doesn’t show up too well in the pics, but there is a 25mm/1 inch gap between the batteries and the block walls, and the batteries are sitting on a hard wood pallet….

In this part of the world, heat is much more of a problem than cold.

17 08 2011
Travel the World

Really cool that you’ve taken the time to put this together.

Maybe one thing to add would be a simple bullet point list of the materials and brand names you’ve used and recommend? Really great post though. Thank-you!

Jonathan
http://www.GreenJoyment.com

8 09 2011
Ernest

Nice blog
I hope the new inverter is still behaving itself – all that were replaced in that batch now seem to be operating well. It turns out that a supply of transistors used on the board were sub standard for the performance required.
A note on the solar panels – we have received several comments from people using this model solar panel that they are consistently measuring output from the array to be over that which it theoretcally should be – to the tune of 20% in one case ! I would be interested if you have the opportunity to investigate the performance of your system also.
Keep up the great work of communicating the benefits of this technology.

8 09 2011
mikestasse

Hi Ernest, I’m surprised anyone gets over performance from their panels, because we consistently get under. IMO, they perform disappointingly in the heat, I rarely see more than 1.6kW from the 2.2 kW they are rated at. The only time I’ve seen 100% output is after a prolonged time of shading by a dark cloud in the middle of an otherwise sunny day when thy have completely cooled down, and then suddenly exposed to full sun……… it doesn’t last of course, you can see the numbers roll back down as soon as the heat starts accumulating back in the panels. I just assume it’s on par with the derating process of all crystalline panels.

The inverter seems fine now, no problems there. You can come any time and have a look, you know where we are!

21 09 2011
len

if we are very lucky after building this new home we may yet be able to dabble in some solar + also wind generation:

a ball park figure from friends suggests that using 12 X secondhand fork lift batteries (tested to 80% capacity), 4 solar panels (to around 15k/w cap’, an inverter and a wind generator at around $6k not including brackets and wiring. hope we can go that way some?

would never be interested in getting into bed with gov’ or rip off power authority who have judged mike by their own merits, and in the process wasted a lot of valuable money, how many other such cases have there been one would wonder.

anyhow if we can just doing solar could be around $3K = give or take.

len

17 01 2012
Don Smith

Hi Mike,
Have seen your posts on Martenson for some time and wondered where you come from. Now solved. It was from Chris’ site that I came across your blog. I have followed much the same path that you have with regard to collapse. However I have tried to work out just what level of technology and resources would be available after a collapse. As a result I have considered PV power to give me a 20 year breathing space only. What are your thoughts on this. BTY I thought my 5kW/day was good – 2.5 is terrific.
Don S

17 01 2012
mikestasse

Hi Don…..

Yes I agree, we only have a 20 yr window with EVERYTHING! My batteries are unlikely to last more than another 10 years (but then again will I even outlive them!?), and who knows how long the electronics attached to the PVs will last…. I’ve already had to replace the newest inverter twice under warranty, and the other (now seven years old) German inverter seems to be working as well as it ever has, design faults and all.

11 04 2012
michaelbarring

Hey there..!! A new idea will be developed, or suppressed, by the
party with the most money, and/or support from the
government, including the courts, not the inventor.

The good news is that there is a flood of new ideas
waiting to be implemented, as soon as the gates of
the damn dam are opened, hopefully in time to save
the US from its existential economic crisis.

20 05 2012
adriano

how is going your solar system? is still poducing profit to your wallet?

can you give some details about the costs of the panels and if you know any place where to buy them? regards!

4 06 2012
Greg Bell

So, you got burned by Chinese batteries and then by a Chinese inverter. How are those Chinese panels on top holding up?

4 06 2012
mikestasse

Well, so far so good. I think the inverter problems were a freak set of coincidences, because when I did some research on related forums, no one had anything bad to say about the Kinglongs….

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