-
<p>Just had a completely random call from some old fluffybunny in Melbourne. He had our number, and I wondered why - after we moved house, we kept the same ISP, who does our landline, and I asked for silent number years ago.</p>
<p> </p>
<p> </p>
<p>So this prick had left a message, and the only reason I called him back was to find out how the got the number.</p>
<p> </p>
<p> </p>
<p>Then I remembered that we had to get a new number (moved exchanges) and therefore all the settings were blown away as it was technically a new account. FFS. I also discovered the guys who can help with that are only Mon-Fri business hours. Gah!</p>
<p> </p>
<p> </p>
<p> </p>
<p>Anyway, he had a good old rant and rave about the Powerwall and why did I choose it, how did I know it would do what they said, what about Depth of Discharge factors and all that shit. Then he finished off by calling the government fucking fluffybunnys and how he'd tried to set up his own 100kW solar farm but got blocked at every stage by bureaucrats.</p>
<p> </p>
<p>Fucking stalkers!</p> -
<p>Today was generation of 24.7kWh - not bad as, looking at the bills, my summer is peak at around 25kWh on average, and that was with the old pool pump and old habits.</p>
<p> </p>
<p>I thought I'd grab some of the output (screenshots) of the online tool that the SolarEdge inverter provides. At some point I really need to get that API going...</p>
<p> </p>
<p>In any case - see attached image:</p>
<p> </p>
<p>[attachment=1960:timeofday.png]</p>
<p> </p>
<p>Left image is today. You can see a few dips here and there, as cloud cover moved around the place and interrupted the level of light. But overall, once it hits what I call "useful light" at around 11AM, its still delivering fairly consistently at that 2kW+ level.</p>
<p> </p>
<p>Right image is the best to date (2nd Feb) which basically had no cloud, and wasn't too hot. That thing just cranks up to over 3kWh from 10AM - 4PM, with the odd dip due to reading inconsistencies, or sometimes excessive temperature. Bloody amazing that its still picking up good light (over 1kW) until 6PM then trailing off.</p>
<p> </p>
<p>The key thing to note is that lab testing of a 5kW system like mine for a Sydney latitude are rated at 19.5kWh per day generated across the year. Most of those calculations are done on a 3.9 "peak sun hour" average. I believe that figure does take weather (cloud) into account, but I've also seen calculators that quote Sydney sun as 4.8 hours per day.</p>
<p> </p>
<p>The lab tests are a few years old now, and I think the technology, particularly micro-inverters, has nudged that figure up a little because panels are simply better at catching the light. My array faces almost right on NNW, and to the east is the ridge I've mentioned which basically excludes morning sun. However, being northwest I reckon I've got the best of sun from about 10AM onwards, year-round. If I make 5+ hours a day, the ROI will be a doddle.</p>
<p> </p>
<p>But those wet weeks we sometimes get here .... :ireful: When that sort of thing happens, it'll be a case of tightening the belt a little on power usage, and selling what I can out of the battery to maximise income versus spend on grid.</p> -
<p>Hit 31.86kWh today, despite a little cloud between midday and 2PM. Main thing was air temp didn't get up past about 28C allowing the panels to get near their most efficient output.</p>
<p> </p>
<p>Autumn and Spring should actually be quite good months for power reselling, given I use about 25% less power than summer and the temperatures are actually better for solar panel peak efficiency. Less daylight of course, but maybe better bang for buck overall.</p> -
<p>Here's a bit on the Reposit thing I keep talking about in regard to GridCredits:</p>
<p> </p>
<p><a data-ipb='nomediaparse' href='http://www.solarchoice.net.au/blog/resposit-power-gridcredits-trade-homes-energy-on-grid'>http://www.solarchoice.net.au/blog/resposit-power-gridcredits-trade-homes-energy-on-grid</a></p>
<p> </p>
<p>So the feed-in tariff for most electricity companies are 5-8c / kWh under current rules (older schemes, which are expiring this year, were 40-60c! Then again their systems were more expensive, and quite a bit smaller). If I can start selling at a higher rate than I pay, then I can use the battery purely for generating profit, and buy power back in the evening, knowing I'm still net zero.</p>
<p> </p>
<p>We'll see.</p> -
<p>Got the battery management hardware installed and firmware update to the router today, so I can actually track input/output rather than just power generation</p>
<p> </p>
<p>Only been running a couple of hours all up after being out of commission all day (lot of wiring for the sparkies) so the power stats today aren't great.</p>
<p> </p>
<p>But now I can see consumption, I can start looking at habits. And I tell you, that fucking ducted air con is a big threat at this point. The fluffybunny who built this house probably bought the cheapest, nastiest piece of inefficient shit he could find, based on what he did with the other bits and pieces.</p>
<p> </p>
<p>[attachment=1962:20160209_solaredge.png]</p> -
<p>Along with changing habits do you reckon you'll end up replacing other gear to get more efficiency? Guess it'd be tempting if you had some appliances that were juice monsters... hope the air con isn't as big an issue as feared.</p>
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<p>I've taken care of some things already - LED globes everywhere in the house (except that <em>one</em> light fitting Mrs TA wanted in the guest bedroom :mad1: that thankfully isn't used that often).</p>
<p> </p>
<p>In the First World Problems category the TVs in the house are all LED and therefore much cheaper to run than a similar-sized plasma, and each of them is 32", 42", and 55". Obviously when idle they consumer bugger all (the 55" is 0.3W idle, the others a bit less) but when running that obviously cranks up to 146W in case of the case of the 55". But look at it this was:</p>
<p> </p>
<p>If I ran that TV for a solid two hours, it would use 292W, which is 0.292kW, so about 6% of what the solar panels can provide on maximum, or around 5% of the battery capacity if the sun has gone down.</p>
<p> </p>
<p>I have network appliances (network switch, modem, VOIP, Wifi, backup storage) that runs around the clock but I've tried to balance best-of-breed with green credentials in that department. At least one of them is probably due for replacement, and I can also put timers on some of that stuff in order to cut down standby during the midnight-6AM period. Just sometimes I get woken up because something at work has fallen over, and people be bitchin at me to log in remotely and fix stuff.</p>
<p> </p>
<p>The other AV equipment (Sonos PlayBar + SUB) consumes a bit more on standby because of the way the amplifiers are configured to start up instantly via the Wifi or TV connection .... you know what? I should make a list of this stuff and figure out what the bad ones are :think:</p>
<p> </p>
<p>Thanks for the idea PK! One thing I might have to kill is the TiVo - continuous consumption of 40 watts = 8 of my LED lightbulbs running all the time!</p>
<p> </p>
<p> </p>
<p>Here's another shot of the system right now. I believe this means the house is consuming 0.67kW, of which 0.65kW is coming from the battery, and the remaining 0.03kW is coming from the grid.</p>
<p> </p>
<p>[attachment=1963:20160209_solaredge2.png]</p>
<p> </p>
<p> </p>
<p>So that is pretty low consumption considering two TVs are running, and this PC with spare (LED) monitor, fridge, and fairly normal lighting with a ceiling fan or two. If that continues for the hours I don't have sunlight, then I'll get about 8 hours out of the battery.</p>
<p> </p>
<p>But considering, once everyone goes to bed, that there is only one TV running, and its the smallest, as well as less lights, computers etc... well, the battery might last longer than anyone expects.</p>
<p> </p>
<p>Ideally, it would get us through to morning including breakfast, then the panels take over again.</p>
<p> </p>
<p>So many stats to collect.....</p> -
<p>First compelling stat produced: ducted air con is, as expected, a power hog. Running at fairly low speed, I tested turning it on and refreshing the stats, and it started sucking 5kW without breaking a sweat.</p>
<p> </p>
<p>So that'll be worth monitoring, particularly the wife's inability to stand anything over 23C.</p>
<p> </p>
<p>Might mean mitigating the heat on the western side of the house with some form of exterior window blinds to lower the heat transfer.</p> -
<blockquote class="ipsBlockquote" data-author="NTA" data-cid="557607" data-time="1455012224">
<div>
<p>First compelling stat produced: ducted air con is, as expected, a power hog. Running at fairly low speed, I tested turning it on and refreshing the stats, and it started sucking 5kW without breaking a sweat.</p>
<p> </p>
<p>So that'll be worth monitoring, particularly the wife's inability to stand anything over 23C.</p>
<p> </p>
<p>Might mean mitigating the heat on the western side of the house with some form of exterior window blinds to lower the heat transfer.</p>
</div>
</blockquote>
<p> </p>
<p>Thats the thing I've found when looking at it. The solar / powerwall combo is great, so long as your house is REALLY smartly built. Double glazing, insulated walls, underfloor ground source heat pump etc. Most houses - even those supposedly up to modern stardards, are stunningly shithouse at keeping whatever heat / cold you have inside from leaking. Even simple shit like having your living rooms face the right way.</p>
<p> </p>
<p>I fricking love Grand Designs (the TV show) and all the eco houses on that the power sources are the least of the cost, its the insulation that sends the price way up. </p>
<p> </p>
<p>Lets face it, you'll test run it for 3 years, learn all the ins & outs. And then buy a block of land & build a new build using all the data you've pulled together to get a house that barely draws anything using all the cash from your click-thrus on your blog.</p>
<p> </p>
<p>Hell, it'll be an episode on Grand Designs.</p> -
<p> :lol: I'll have to do it solo - wife says she's never leaving this house!</p>
<p> </p>
<p>If I <em>was</em> to go on something like Grand Designs, without shadow of a doubt it would be a earth-sheltered house. Energy efficient, basically fireproof, no need for air con or heating, and accessible for self-sustainability. Throw some panels on a couple of Powerwalls in there, and you're off-grid for life.</p>
<p> </p>
<p><a data-ipb='nomediaparse' href='http://www.baldwinobryan.com/'>http://www.baldwinobryan.com/</a></p>
<p> </p>
<p> </p>
<p>In terms of power consumption, I think early on I said my annual average was 22kWh / day which costs me roughly $500 / quarter after discounts. The sparkies, who are specialists in solar installs, said that for my house size, that is pretty bloody good. Some of the places they've installed power were spending $900 a quarter on power (equates roughly to 40 kWh/day) in a house not much different to mine. That indicates to me that some people go overboard on the shit they buy to run without really thinking about the consequences. I'd LIKE a 75" television, but I don't really NEED a TV that big. My consumerism has limits :)</p>
<p> </p>
<p>The guy from the inverter support team (who provide the web portal) said I should expect 80-90% savings, and that would mean ROI is 8.8-10 years. I'm going hard for 8 years, and the Reposit stuff should help.</p>
<p> </p>
<p>The ducted unfortunately is here to stay, but we don't use it much except summer and winter, which we can cut down a lot if the wife just puts another layer on. To install a couple of split systems would be a few thousand, then the ROI just extends outwards.</p> -
<blockquote class="ipsBlockquote" data-author="NTA" data-cid="557614" data-time="1455016558">
<div>
<p> :lol: I'll have to do it solo - wife says she's never leaving this house!</p>
<p> </p>
<p>If I <em>was</em> to go on something like Grand Designs, without shadow of a doubt it would be a earth-sheltered house. Energy efficient, basically fireproof, no need for air con or heating, and accessible for self-sustainability. Throw some panels on a couple of Powerwalls in there, and you're off-grid for life.</p>
<p> </p>
<p><a data-ipb='nomediaparse' href='http://www.baldwinobryan.com/'>http://www.baldwinobryan.com/</a></p>
</div>
</blockquote>
<p> </p>
<p>I fricking love those.</p>
<p> </p>
<p>All you have to do is find a non earthquake area, so anywhere in NZ other than the North Island. Or South Island.</p> -
<p><a data-ipb='nomediaparse' href='http://www.vox.com/2016/2/5/10919082/solar-storage-economics'>http://www.vox.com/2016/2/5/10919082/solar-storage-economics</a></p>
<p> </p>
<p>Vox talking about Solar + Storage</p> -
<p>Will give that a listen at home.</p>
<p> </p>
<p>In other news: the battery has topped up as of 1:45PM local time (DST) today - 12:45 standard time.</p>
<p> </p>
<p>If the house is consuming around 0.5-1kW when we're home in the evening, I'll be able to run anywhere between 6-12 hours I reckon. Have to see how the Lithium will perform over time, and ensure minimums are set in regards to Depth of Drain.</p>
<p> </p>
<p>Never want to take a Lithium battery to 0% on a regular basis as it fucks the chemistry. But they recommendation of 20% minimum I reckon can be pushed a little. Will talk to the inverter guys about how to set that up.</p>
<p> </p>
<p> </p>
<p>[attachment=1964:20160210_solaredge.png]</p> -
<p>A little test when I got home this afternoon - knowing it was in the mid 30s and the wife was just going to punch the air con when she got home, I decided to beat her to it.</p>
<p> </p>
<p>This is a before and after shot of things as they stand. Taken about ten minutes apart around 5PM:</p>
<p> </p>
<p> </p>
<p>[attachment=1965:20160210_AirConComparison 5PM.png]</p>
<p> </p>
<p> </p>
<p> </p>
<p>Therefore, the ducted air con required about 6.15kW to operate, of which it pulled all the panel generation at that time of day (2.55kW), power from the battery (2.45kW, which would deplete it in under three hours), and still needed feed from the grid (1.48kW).</p>
<p> </p>
<p>Battery is now at around 57% because the panels at this time of day start to run out of puff, so it replenishes slower. And I think the thermostat on the air con is fucked, because I set the damn thing to 25 and its gotta be colder than that!</p>
<p> </p>
<p>Thing is, the west side of the house is where the kids rumpus and the garage is, so it cops a beating. I've floated the idea of putting up awnings on that side of the house, but Mrs TA is against it. She'd rather watch our money burn...</p> -
<p>Put the dishwasher on the shit list. FFS its like the fluffybunny who built this place bought the least efficient appliances just to piss me off... Next time we come around to replacing the kitchen stuff, the star rating for these fucking things is going to be a LOT higher.</p>
<p> </p>
<p> </p>
<p> </p>
<p> </p>
<blockquote class="ipsBlockquote" data-author="gollum" data-cid="557627" data-time="1455026250">
<div>
<p><a data-ipb='nomediaparse' href='http://www.vox.com/2016/2/5/10919082/solar-storage-economics'>http://www.vox.com/2016/2/5/10919082/solar-storage-economics</a></p>
<p> </p>
<p>Vox talking about Solar + Storage</p>
</div>
</blockquote>
<p> </p>
<p>Addresses a point that a lot of analyses here are missing: selling back to the market. At present, I'd get 5-8 <em>cents</em> per kW I distribute off the panels. So, if I had a good day, maybe $1.00 / diem.</p>
<p> </p>
<p>That Reposit mob I was talking about are very enthusiastic, and the GridCredits scheme is looking at up to $1 / kWh - so on a good day I could sell the content of the battery (topping it up off the panels) for $7.00 / diem. Not that I probably would, because good days are not the majority.</p>
<p> </p>
<p>But with the algorithm they've developed to look at usage, weather, a grid requirements, anything above $85c that day will cover my daily connection fee, and everything after that offsets my import charges.</p>
<p> </p>
<p>The good news, this morning, is that the software I have is reporting enough battery to get us through breakfast and to work. Thanks to Mother Nature for providing us a cool afternoon where the wife didn't feel the need to scramble for the air con. The missing graphic is the solar panel, which is doing fuck all anyway, this time of morning.</p>
<p> </p>
<p>[attachment=1968:201602120625 - Copy.png]</p> -
<p>Been playing around with the web portal supplied by the inverter mob, and looking at how they do charts etc. I'm not convinced the data is 100% accurate - the installer said it may occasionally go a small percentage over or under because of electrons and shit - its pretty close. Occasionally I see the battery feeding the house AND the grid, but they said it could be a bit of feedback as the circuits switch direction. They'll check it out.</p>
<p> </p>
<p>Here is an example of one of the power graphs they provide which shows various click-on/off options in the GUI - some of this data I can actually use later to chart it on the blog I'll set up, in different layouts. Should be fun.</p>
<p> </p>
<p>You can see from this a graph of power ins and outs recorded for the last 24 hours or so. </p>
<p> </p>
<p>[attachment=1971:GraphExample.png]</p>
<p> </p>
<p>The first massive red spike (consumption - first arrow) is the air con going on around bedtime for the kids (bit stuffy in their rooms) last night (12th Feb) and the battery trying to keep up with it. The battery has a peak output of 3.3kW and did valiantly, but the ducted air pulls anywhere from 5kW upwards based on recent experience with this interface, so that is always going to hit the grid for some of its power.</p>
<p> </p>
<p>Then, during sleepy times shortly after that, the battery (blue) is keeping up easily with the power needs. Due to the bathroom light being on, and various other things like the alarm system, TVs on standby, devices charging, fridge etc. the house draws about 200W on average from the battery over the 6 hours from midnight.</p>
<p> </p>
<p>As we move toward 0800 hours, the NTA Clan are on the move, using power for breakfast activities and turning on the TV and stuff, and the solar generation also starts. Was a fucking mint day for it in terms of cloud, as you can see by the green curve. Just gunned up to 4kW by the middle of the day, then declined gracefully toward evening. Another 32kW day! But why didn't it really go over 4kW? The answer is in the panel efficiency: ideal temps are 25C, so anything about that and you start to lose a few watts here and there.</p>
<p> </p>
<p>But you can see around 2PM (second arrow), the air con went on again as the temp started to climb into the high 30s and even my sense of economics took a back seat to Mrs TA's need not to sweat (and no, I have NOT broached the topic of menopause - I want to live to see this system hit ROI! )</p>
<p> </p>
<p>As we tail off toward evening, everything is fairly stable, with another little spike (third arrow) showing where Mrs TA used the hair dryer after being in the pool. </p>
<p> </p>
<p>Right now the battery is supplying the house needs of of 0.47kW as the kids are in bed, one ceiling fan running, and this PC plus the fridge etc. I have 30% of the battery left to play with.</p>
<p> </p>
<p>Here is a zoomed in version of midnight to 6AM.</p>
<p> </p>
<p>[attachment=1972:graphzoom.png]</p>
<p> </p>
<p>Looking at it this way: if I go to sleep with about 30% of the battery available, keeping in mind it cuts out at 5% to preserve itself, the house can run for around 8 hours in "standby" mode without calling on the grid. That may shorten over time as we tweak battery settings, and as summer dies off and I don't need the air con and have more available in the battery for night time, sleep time, and breakfast.</p>
<p> </p>
<p>It looks a fairly good argument for a 95% reduction in grid usage alone.</p> -
<p>Also: its going to get to 39C here tomorrow, so we need to get the fuck out so I'm not burning my money in that fucking ducted system!</p>
<p> </p>
<p>And the polyphase (multi-directional) meter is installed on Monday apparently so I can start getting money for all the exporting I'm doing.</p> -
<blockquote class="ipsBlockquote" data-author="NTA" data-cid="558538" data-time="1455361367"><p>Also: its going to get to 39C here tomorrow, so we need to get the fuck out so I'm not burning my money in that fucking ducted system!<br>
<br>
And the polyphase (multi-directional) meter is installed on Monday apparently so I can start getting money for all the exporting I'm doing.</p></blockquote>
<br>
But you'll spend money driving, buying lunch, drinks etc
Solar Power and Storage - a nerd's view