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Forum Index : Solar : Advice on new solar set up for home and workshop
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| Warpspeed Guru  Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Boppa, It seems that polycrystalline panels do in fact out perform monocrystalline panels in awful conditions. I have 2Kw of each both facing north. The monos are just slightly better in a clear blue sky. Cheers, Tony. |
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renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Boppa, I too have a mainly east west array, simply because of my roof, and it's great in summer as the sun is much further south. However in winter when the sun is much lower north in the Melbourne sky the east west is hopeless compared to the north facing panels. BUT when we get that sh*tty melbourne light even cover cloud, it tends to act as a filter and spreads the UV all around, so the east or west panels do just as well as the bloody north ones. So I think if you are in the more southern parts of Oz it's better to have north facing, further north it's better for east west. That is with an off grid system in mind BTW. In summer you'll have gobs of power, what you need to worry about off grid is the winter supply. Cheers Caveman Mark Off grid eastern Melb |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
I'm up in canetoad land, which is probably why my east/westers work so well I found even in winter, I was consistently ahead of the neighbours system for total output for the day, and overcast, well ahead I'll be starting with 15kw to begin with, I could comfortably double that on the shed roof without running out of space (east/west) thats 9x15m plus a 6x8 skillion roof garage/leanto facing north I want to see how it performs over winter, summer levels are comfortably higher than my expected usage anyway, if winter shows it coming up short, well more secondhand panels aren't expensive here, just keep adding until it can handle anything I throw at it... Even doubling the panel capacity leaves me well under the install cost for the grid... (the batteries are the largest cost by far) |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Winter is always going to be the your biggest problem, especially when there are several totally grey days in a row. As Mark says, extra panel area is what you need, and when its grey, the direction makes very little difference. Even several Kw of south facing panels will work just as well under those conditions. But when its really bad for several days in a row, even if you double up on panels, twice nothing is still going to be nothing. And you will definitely need some backup power, either from the grid or a generator, perhaps for just a very few individual days per year. Cheers, Tony. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
The critical factor is your usage. I have 20kw+ of panels and it's not enough for winter and far as I can see, never will be with any practical amount of panels. The thing for me is not the fact the outputs per say are lower in winter, My output is still not bad being double overclocked on the inverters. It's the fact the days are 8? hours instead of 14 in summer. Its the generation TIME not the output that's the killer. If I did the lower winter outputs for the same time I get in summer I'd be laughing. I turned half the systems off last summer and still had more power than I knew what to do with running the AC more than in winter. We heat with AC and that is the killer. If I can eliminate that load, then I'll be fine. If you heat with wood or gas, then your power generation will probably be OK too even if you have to be a bit wary and take it easy where you can in the bad spells. The other thing I notice that Pulls a LOT more power in winter is the hot water. We are using less power in Total atm even with a couple of hours a day of AC cooling than what the water heater uses alone in winter. inlet water temp is 20o +- warmer now and that makes an impact even if the consumption is exactly the same. I wish I could have summer generation in winter and winter generation in summer. That would work out very nicely. I'm looking at an oil fired boiler this winter and If I can take the heating load off, we'll be laughing. Failing the boiler, I have run the numbers on one of those Diesel van/ truck heaters. I believe it will work out cheaper than the electricity short fall we have to pay for on diesel and there is always the option to run about 25% veg or make Biodiesel which I think will be OK in these units. I estimate will be around 35-40C litre for the bio which will put me well in front. |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
My current usage is 7kwhr a day (we even have aircon, but it's only used during the hottest days, the ceiling fans are more than enough for most days), and it simply doesn't get cold enough to really warrant running it as a heater, we occasionally get down to single digits here, but I lived for years in places it got really cold in winter- freeze the dogs water bowl cold, and up here, what the locals think is cold is still teeshirt weather for me lol I have over three years of usage figures for the area (admittedly grid tie- but that doesn't affect the panels output) and although my usage will rise with the workshop, it's more a hobby than a 'must run' for that, so on extended cloudy days, well I'll surf the net instead lol Should things get desperate, well I still have a choice of gennies to select from, but even the current 6kw covers the usage in all but the most extreme conditions, and having two and a half times more panel capacity, even those would have (just admittedly) covered my current daily usage A lot comes down to selecting low usage devices, and eliminating parasitic loads, before even getting the panels, we eliminated well over half our existing consumption with newer, high efficiency devices- the fridge was cut by over a third with a newer fridge (270 down to 90w), TV went from the old plasma (500w, down to under a hundred with a new led- and that was on 8-10 hours a day!) I think it was Grogster that first clued me into the washing machine, I checked ours and it was using as much sitting all week doing nothing as it did in actual washing clothes! Led lighting on the ceiling fans now uses less with every light in the house on, than we previously used in the loungeroom alone (2x 3 bulb chandeliers with 45w bulbs in them!) |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Our normal day is 10kwhr with the elec oven going, and generally being frivolous with power, tv's going and not being watched, lights on in rooms no one is there etc. We have been as low as 6kwhr when actually watching things closely, not being a total miser, but just being sensible. We got through last winter just fine with 12kw of panels. But with 1000ah storage that was the key, some days it would get run down a bit, maybe use 8 and only put in 4, next day use 6 and put in 4, next day use 8 and put in 5, next day it would be sunny and finally give it a proper charge. So with your low usage and planned 15kw of panels you'll be just fine with that system and your backup gen. With a decent battery you won't need the gen. Cheers Caveman Mark Off grid eastern Melb |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
I have been preaching this mantra for quite some time and it has brought about a very mixed response. At one extreme, there has been huge exploding anger "I don't want to live like a freakin peasant" I just want you to tell me exactly how to build a low cost solar system that will provide all the power I will ever want. Duh. But there are some very significant gains in power reduction to be had, by making a few simple changes here and there, while sacrificing nothing in convenience or lifestyle. The trick is to monitor every individual load for at least 24 hours, and base some decisions on that. There are going to be some really big surprises, and sometimes very simple and easy to implement solutions. The peak winter problem probably comes down to two choices. Either a much larger and more expensive battery, or an expensive generator. Probably not a great difference in final outcome, but for various reasons one might have more appeal than the other. Both are going to require some regular monitoring and maintenance. My own solution to this will eventually be a low powered standby dc generator (1Kw) that will cycle in and out automatically whenever low battery voltage is detected. It will run on natural gas so that no manual refueling will ever be required. If that runs for five to seven hours each twenty four hours it will cover my total loading in mid winter with absolutely zero sun. Edited 2019-11-22 09:18 by Warpspeed Cheers, Tony. |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852 |
Haha ... though after many many years of 'push back' from wife and teenage daughters on any hint of moderation or conservation, a man gets tired. I have to admit, I had some wins ... so not all wasted. Now the girls are off to pay their own bills ... this is going to be interesting to watch.  I think one of the biggest for me was when you mentioned the automatic garage door controls. I've had one off ever since ... but the other one I still have to address. I had a pretty good handle on everything else and what they use. Are you off grid yourself Tony, or are you planning to? I like the idea of natural gas, but we only have bottled here ... even though a huge gas mains goes down our road. I did look at the generator idea ... but that then brings in the maintenance and wear ... and five to seven hours each twenty four hours is going to add up too ... though I suppose it is only so many days a year. Cheers, Roger Cheers, Roger |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
That's why I'm going for the 48v lithiums, yes they cost more initially... but... A 400ahr lithium bank can be expected to get 15 years with a 80% DOD, 20 years with a 70% DOD (giving me 320Ahr/15360 and 280ahr/13440whr) In comparison, a 400ahr gel L/A with a 50% discharge gives me 200ahr/9600whr, but only 3-5 years and costs a third of the price, drop the DOD to 25% and you could stretch it out to 8/10 years, but effectively only have 100ahr/4800whr available... Jumping up to Marks 1000Ahr battery bank, you still get 3/5 years at 50%DOD (500ahr/24000whr), drop it back to 25%DOD nightly and you increase it to the normal 8-10yrs, but now are back at 250ahr/12000whr- slightly less than the lithiums, and a purchase price not that far off the 400Ahr of lithiums- and still at half the life expectancy... You can get 12-15 years out of L/A, I did it years ago in my first offgrid place, but only because I had access to extremely cheap batteries and had a huge bank in comparison to my usage at the time (I literally ran for over two weeks when my first set of panels were destroyed, just from the battery bank) but that was back then, when I could get only 3 year old batteries for literally the price of my fuel to pick them up and take them home, (ex government batteries swapped out at 3 years, regardless of condition, can't remember the exact capacity, but there were 3 wooden pallets under the leanto filled with huge ex railways batteries on a 24v system)- once they got to the magic 3 year mark, they tossed them out... Bet they don't do that anymore...  |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
I'm one of those mixed responders. There is no doubting the logic and sensibility of what you are saying. There are other factors involved though. Perhaps you just live with the Mrs who understands. My Mrs and My daughter don't and frankly, it's not worth the aggro for the few bucks saved. My priority is a quiet, stress free life and it's hard enough managing that with the daughter as it is. I invested in a ship load of panels and 8 months of the year we have ample power to a ridiculous amount in summer. I FULLY understand how in an off grid situation that could be different and then one would be very wise to follow your advise.... as always. I can well see that being the case. I have been long thinking about getting one of those PIR sensors and wiring it to a timer and putting it in front of the TV. When no bugger is moving in front of it, IE, they have left the room of fallen asleep in front of it, the thing switches off. Don't care about the power but having gone through a stack of TV's since the old tube jobs went the way of the dinosaur, I'm more concerned about longevity. New TV's seem crap. We are up to 3 Now that haven't even lasted 18 Months and my father has had one too. Maybe there are other things that would be good for the person monitor as well? I'm probably the worst offender with leaving things on, (apart from my daughter with her hair straightener going all day which I did level fire and brimstone at her for from a perspective of burning the house down) because I never turn my computer off. Goes into standby and the monitor shuts off but still using stand by power. I have read washing machines can be power hogs when not in use as well. I do knock that off as the plug is very easy to reach and the things are very susceptible to power surges I have been told. I think it would be an absolute exercise in futility to try to get my daughter to unplug all the chargers she has in her room. There must be 10 of them for all sorts of things that get plugged into the devise to charge it and then plugged into the mains when the devise is removed. I see she has got some of those induction charger things for her crapple devices and they are pretty inefficiency I hear. I have been saving some power with a small panel and a USB charger I got. She has an power pack battery for her phone and thing that's looks big enough to start a car. I put that on the solar charger through the day and she uses it at night to charge things up because it's high output and charges them fast. I bet I'm saving a good .5C worth of power a month with that! :0) My winter power problem comes down to heating without question. No gas here, don't want wood really, would work out more exy to buy as I don't have a free source and if I did, I know the work involved trying to keep my fathers supply up and don't want a second lot of that. If I can get my oil burning or diesel heater going this winter, we'll be fine. The input from the panels will cover everything else. Have you done the calcs on the cost per KW hour you will be getting given losses etc Tony? I'd be very interested to see the cost comparison. Going this road you would really have to add your gas and power bill together to get the real cost of your household energy usage. As you might have noted, I am diesel and Veg oil obsessed ( as well as solar). A modest 3kw Diesel Generator would give you the output you mention in 2 hours or so and probably use about a litre of fuel ( oil ) to do it. If you had a 200L drum of oil, You would probably refuel the thing once a year if that. Maintenance would be change the oil and over precautionary and the only other thing would be collect and process the oil . For that amount should take 4 Hours if that. Yes, it's more mucking round than your proposal but 4 hours a year isn't a lot for the benefit. The time is offset and paid for by free power and to some of us, that bit of mucking round is actually fun and enjoyable. :0) Edited 2019-11-22 10:18 by Davo99 |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
Could you give us an idea of the cost/ size of the lithium's you are looking at? |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
Winstons from Trev (same as in his ute but bigger capacity) already installed a set in the ute about three years ago (baby little 60ahrs) but they gave the same runtime on the fridge as 2 90ahr L/A at less than a third of the weight, and they fitted nicely behind the utes coverplate (ie in between the outer skin and the utes inner tub) About $12g for the batteries 400ahr each cell is 13.5kg, 48v is 16 cells Edited 2019-11-22 10:36 by Boppa |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Boppa, it's not unheard of for people to get 20 years from a fork battery. They are big, heavy, gas when charged, and need to be topped up with water, so no way near as user friendly. But they will last a long time. I very rarely have mine below 51v, not sure what did that would be, but it wouldn't be much. Edited 2019-11-22 11:07 by renewableMark Cheers Caveman Mark Off grid eastern Melb |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
I've heard of a few, but only when only very lightly loaded... (and yeah, my old house required a check every month, usually only topped up every 2 or 3 months, but with the number of batteries I had, took probably 1/2 to 3/4 of an hours, and you inevitably ended up with battery acid on you, I had the 'holes in clothes' grunge look long before it became popular with the teenagers lol) The lithiums well, they are literally set and forget These will likely outlive me... (quite likely in fact) (remembering that my current daily usage is around the 7kwhr a day... less than 50%DOD on them) Edited 2019-11-22 11:26 by Boppa |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
In that case, may as well get the leads and put the savings towards having a good time while you are still here! :0) |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
Well I am hoping to be around for a few more years lol, but considering that they go from >5000 cycles at 80% to >7000 at 70%, and most of the year will be well under 50% DOD, I can see them lasting a very long time indeed... (it's not as if I really need to scimp out on the cost, my new 'toy'mill and lathe will cost more than the batteries anyway- hell I'm spending more on insulation than the batteries!!!) This is my 'retirement house' and I got the money, so I plan to use them as an 'experiment' just to see how good they are.... (it's the major reason I went rural- my old house was rural when I bought it, but is now literally in the middle of a subdivision!!!- not the best spot any more to start playing with loud metal cutting equipment... for hours a day...)  |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Bloody corrective text, I meant DOD not did. Actually I never even thought to calculate that till now. Cheers Caveman Mark Off grid eastern Melb |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
When I was in suburbia, I made a TON more noise than what I do now. One side was vacant and had been for years, The other side a bunch of self important inconsiderate arseholes built an Illegal Duplex. Gave us hell when they were building it so I repaid them back with everything I could come up with. They were never going to call the cops, didn't want any attention to one's illegal home business and the others drug dealing. I did whatever I wanted and went out my way to annoy them for the hell they had put us through. I think I succeed. Now I'm here on acreage I have great neighbours which aren't all that far away. I try very hard to be as considerate as possible and not annoy them at all. They are real good nice people. One is away a lot and I look after their animals sometimes and the other side is a tinkerer and DIY'er himself so always bashing or grinding something. I don't think there is a day when he doesn't fire Up his Ride on, I think sometimes he just likes to listen to it. He never worries me and apparently when I do make noise, even with the couple of party's the daughter has had, they say they never hear anything and aren't bothered in the least. Sometimes I miss torturing the old neighbours and getting payback but living in peace and harmony is SO much better. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Just a tad bit disturbing mate. Cheers Caveman Mark Off grid eastern Melb |
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