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Forum Index : Solar : Grid connected inverter off grid
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Madness Guru  Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
If you replace all your lights with LED ones they use bugger all. We use an electric oven also they are not quite as bad as you think because once it is up to temperature it cycles on and off to regulate the temp. If it is 2400W like ours you can cut that in half so if it is on for 1 hour it uses 1.2KWH. Also if you are able to use it during the day more than you are currently it helps too. My wife was bragging on Facebook recently how we still had power when everyone else around us was in the dark for 24 hours after a severe storm went through. The image below is from my 5KW GTI for yesterday, it is only half of the picture as there is another 4.5KW as well not shown. Power kept increasing up to 10 AM with the sun then the regulator started throttling it back as the battery had reached Absorb volts. Total solar energy generated for the day was 22.2KWH, it was mostly clear skies, due to the regulation it holds it back, I have had around 40KWH in one day. This was after a few days of very cloudy weather so battery needed a lot of charging and hot water was right down as well. I divert power to the HWS when the battery reaches absorb, it can take 2400W most of the day when the temperature is down.  There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
F&P washing machines also last much longer if turned off at the power point, I used to repair them for a living, being turned on with fairly 300VDC on the board causes corrosion over time. Plus they have a habit of letting out the smoke if there is a power spike. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
That's only 525 KWH in a year, reminds me I need to check for all the phantom loads in my place. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
I just dug out the original actual monitoring figures for the F&P. One heavy duty wash (50 minutes) fast spin setting. Highest peak power recorded (spin initial acceleration) 555 watts. Minimum power recorded 3.6 watts. Total power usage for one wash .083 Kwh. Power when switched off 3.6 watts, or 86.4 watt hours (over 24 hours). It doesn't sound like much, but it all adds up. Its not a lot of power. What really shocked me though was that switched off it used more power than washing a FULL LOAD. Cheers, Tony. |
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renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Bloody AC died today, looks like we're getting a new one sooner than we thought.  BUT, it will be a nice new efficient one. Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
No point crying about it, you were going to do it anyway, not the best time of year for it though. You will be doing well to get a new one installed in the next couple weeks. That is unless you do it yourself, outside it is stinking hot and I am inside cool comfortable with my solar powered DIY installed 10KW ducted AC running. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
It would have been nicer to just decommission the old unit and kick it till it bled gas, unfortunately, we are without cooling till it gets sorted. I can do it myself, but I wouldn't get a warranty on it if I did that, $500-600 fitting, prob rather handball. Got someone booked in for the 3rd Jan, so not too bad. Nice efficient new r32 gas unit!!! You ripper!! Cheers Caveman Mark Off grid eastern Melb |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
This is what I figured as well just having put my own solar set up on the roof. Summer yields are double winter so it's not cooling with the AC I have to worry about, it's heating with it. I have a 5KW array atm with a 1.6 temporary. I'd like to get another 5Kw to allow for the AC use summer or winter. I'm hoping 10Kw all up will be enough but if I fall short I could use the west roof of the house although I am reluctant because of the far lesser efficiency of that. I will if I come across them get some cheap, lower wattage panels and look at hooking them up to the hot water system through an inverter. Not sure if that will be financially efficient, spose it depends on how long the inverter lasts. |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
Actually west facing can have advantages, my sisters place has no north facing roof, so it has 10 panels on the east and 12 on the west on a dual mttp controller Power hits its peak about 9am, and continues on until about 4 when it starts to decline My mothers on the other hand has north facers only, it peaks at 11 and starts to drop off about 2 so those split east west panels deliver full power an extra 4 hrs a day- worth it imho, for the small price extra panels cost (we got no aircon here atm, its sitting in a box in the spare bedroom waiting for the sparky to find time to install it- `mid january' is his earliest estimate...) :-( |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
If you told the sparky there was a carton of stubbies waiting it would have been done already :) The 5KW of panels I have laying flat do very well in summer and were still making 2.5 KW at 4PM (Eastern Standard Time, not daylight bullsh*t time), while the panels tilted at 26 degrees facing north have the sun shining on the back of them at that time. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Hey Mad, does the water get into them sitting flat? BTW I told my air con guy I would pay folding cash, he said he'de come as soon as he could pick up a unit from the supplier. Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
No water problems, they collect more dust and stuff so need cleaning more often. On cloudy days there is a noticeable difference in output. Cash or beer works wonders. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Yep when customers tell me they are paying cash they get bumped to the top of the list, way above the real estate agents that normally pay 4-6 weeks. I know how I feel when I hear "folding cash" that's why I always offer it to trades. Cheers Caveman Mark Off grid eastern Melb |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
I crunched a lot of numbers for installing my panels and found that the prescribed idea of tilt should equal latitude to be rather erroneous for getting max yeilds. My tilt should be 34o. Crunching the numbers I found 25o to be much better over all and particularly in summer. It looses a bit in the winter months but those losses are so small I really think would depend on the weather that year than the tilt angle. In any case, the losses in winter amount to cents and the gains in summer are many dollars. My shed roof is 13o and 5o. I wanted to get my test solar farm up off the back grass but I wasn't ready to build the frame not having decided exactly how I wanted to do it or where to put them given I want to extend the shed. I thought for the time being I'll just throw them up there as can't be any worse than on the ground. I thought I'd look up the yeild and was happy to find that from Oct to Feb, the things will make a Lot more power at the lower angles than they will the higher ones. Looking at the difference between the lower angles and the "correct" angle is a total difference of $200 per year in what I pay for power. Again, I think a lot of that in practicality would depend on the weather that year regardless of what your tilt was. Given the savings in time and money of building the frame and more importantly to me, the added storm proofing of having the things flat on the roof as against elevated 600MM like a 9x1.6m sail PER STRING, I'm going to leave them where they are. The winds here get savage and although the strngest winds always would blow along the panels, I'm happier with them laying down where NO wind can get under them. With this in mind, I double secured the end panels as I figure they are likley to have the most stress. The other advantage with laying them on the roof, I was able to secure them using the roof screw holes already there with an L bracket and just putting a tek screw into the panel frame. Brackets cost .40c ea and are more than stout enough for the job. Those panels are going to come apart before those brackets yield. The only other possible disadvantage I can see doing it this way is the lack of air gap ( pretty much) for the panels to cool. They still have some air in the ridges of the corrugated roof but obviously the airflow and convection would be much better with a lot more open space underneath. Whether this makes a damn of difference in the 35-44o degree days we have had for the last 2 weeks, I'm pretty skeptical. When I had them on the ground I noticed the things got too hot to touch on even a chilly day if the sun was out and the sky clear. From memory the ratings of the panels fall off at 40oC so unless the things were in an environment with snow around, I cant see them ever not being above 40o nd the fall off i get in my strings would justify that. Working on 10 Kw of panels, if I put them on my house roof at the " ideal" angle of 34 degrees facing north I would loose 2700 Kwh a year MORE than if I had them facing west. In reality, that could be compensated by adding another 1.8 Kw of west facing panels which wouldn't be a terrible thing and I certainly have the roof space to do it. Not everyone would though. East is a wash for me. I have the biggest muther of a tree in the front yard that is known throughout the district for it's size and age. Time the sun hit any east panels the west ones would have already well come on song. If I took that same 10 Kw of west facing panels and lowered the angle from 34o to 10o ( difficult seeing my roof IS at 34o) I would GAIN an extra 1200 KW yr just by lowering them. 5o would bring another 100 Kw but not ideal for collecting dust and lower ability to self clean. I do see a lot of places where Dodgy installers have put panels anywhere they could regardless of direction or angle. Where my Kids play soccer, I can look at the houses around and see panels facing the grounds from EVERY side. The closest ones are south and I often think that the people in the place probably say panels don't work as they paid all this money and it hardly made any difference to their power bill. Looks only a small system to start with and an older one so probably 1.5 k. I reckon with the tress around as well they would be lucky to get 2Kwh a day out of them. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
I don't have any south facing panels, and for me it would be the most difficult direction to install panels anyway. But south facing, is not as bad as you might expect. At many times of the year actual sunrise and sunset can be well south of the due east-west line. And if the sun is directly overhead, as it might be right now at the mid day summer solstice, you can get more power than you might expect from south facing panels. Its going to be pretty horrible in winter though, when the sun is mainly in the north and never rises very high even at mid day. But if its totally overcast, with a dull grey sky in every direction, south will work just as well as facing in any other direction. But you might still only be looking at about 8 watts to 15 watts of output per panel. In the end, panels are now becoming so cheap, that the more you have the better its all going to work, almost regardless of direction. Cheers, Tony. |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Your latitude less 10 degrees is correct for grid tie, however, this thread is about off-grid. For grid-tie you aim for the most $$$$, for off-grid it is about getting through the worst conditions. So when it the sky is dark and the days are short is what you need to design for. I have seen my 9.5KW of panels making 30 Watts at midday, this was just before a big storm on top of an already dark rainy day. That situation is rare and conditions vary depending on your location, we can get a week of really heavy rain. When that occurs I am lucky to make 5KWHs in a day, fortunately, we don't get those rain events that often. To have enough solar to get through that I would need 30KW plus of panels, twice the battery bank or some other backup source. Others on this forum say they can run 24/7/365 on just solar, here in SE QLD near the coast we do get these big rain events from time to time. It depends on how thick the cloud cover is but there are not many days that I don't get a full charge. When the sky is blue we have power to spare and batteries are at 100% by 11AM, so running an AC that draws 3KW is easy. A cheap petrol generator would last quite a few years as a backup. I know Oztules has people running generators into a rectifier via a run capacitor then to a GTI as a battery charger. The run capacitor in series reduces the amount of power draw if the generator is being overloaded if it is a 3KW GTI and a 5 plus KW generator you may not need to restrict it. Another option is using a Inverter Welder such as this one this is another Oztules idea. I have done this, you need to add 1 more turn to each of the half of the secondary of the biggest inductor otherwise there is no current flow on a 48 Volt battery, 24 volt might work fine out of the box. I have one of these working but I need to spend a bit more time on it to get the current control right. On the lowest setting it puts out 20A but ramps up very rapidly with the slightest turn of the knob. Then there are other options such as wind of micro-hydro power which I plan to have both at the property I am in the process of buying. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
I was going to build one like this Higlander did  here I have an older 42 stator and just recently scored a newer 36, I'll add that to the list of projects. I see a lot of people are using cheap second hand 190w panels, for me that's not an option. My roof is pretty small so I need to get the most from the space. Went and re measured again yesterday. Currently have 8 North on the garage 6 West on the roof Total I can fit 12 West 14 North 16 East 6 South 2 East on the shed if needed. And luckily NO TREES, I would put up a wind turbine but there is a child care centre behind us ( yes VERY noisy) and I'm terrified of a blade coming adrift. I did see those lantern turbines on ebay, look like toys though. Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Wind generators in suburbia would no doubt have the local council ordering you to remove it. My plan is to have a fairly large dam which will be filled by run off from a very small creek, there is then 80 metres of fall to the lowest point. Flow in the creek is about 1 litre per minute during the dry spell we had recently not enough to generate useful power. With rain it is very different though. With the 80 metre fall it takes about 1 litre per second to generate 500 watts going buy several calculators I have looked at. I figure 500 watt continuos with a little solar would keep us going on renewable energy only. At some point, I would like to have an electric car also. 12.5 KW of panels is plenty, have you decided to keep the Aurora GTI? It would work well with 12 panels to the east and same from the west, maybe?? more. Having the GTI works really well with bigger loads during the day and is the most efficient. Even in cloudy conditions, the GTI is the most efficient way to get the most out of the available sunlight. I have worked out the issues I was having the regulator for the GTI, I am working on some changes to the PCB for auxiliary devices before ordering a new batch of them. It will be interesting to see how you go with the F%P charger. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
Do you have any links to that? I asked about doing this recently. I'd love a place I could do MH. To me it is the ultimate in alternative power. I wanted to move to Qld as well. Love the place. I could have bought a mansion around the goldy and had money to spare to buy land behind to put a weekender and play on for what I paid here. Unfortunately the wife and daughter were too entrenched in the Sydney sh*thole so here I am. Least we are now rural and the area is Qld like in the people are friendly and happy. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Yes Mad, I'll keep the Aurora, it's not worth enough to bother selling really, if it can be used down the track I'll hang onto it, however I'll need a sparky to install that part as the rest of my setup is ELV (below 120V) so I can do that myself. From memory the Aurora needed 150V to kit it into gear, it would be bloody nice if that could be lowered. Sounds like you're in a ripper spot for mini hydro, I'm jealous Cheers Caveman Mark Off grid eastern Melb |
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