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Forum Index : Solar : Silicon Chip poor advice on off grid.
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Madness Guru  Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
What you are getting here is feedback from people who are using solar power, some on and some off grid with practical experience. The issue Glenn raised is that what was written is not correct and no one here has disputed that, not because of bias but because that article is outright wrong. 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 |
It seems to me a lot of off gridders go to a lot of what I would call uneeded expense to cover those Dull, windless days with extra generation or battery capacity. To me, while a reasonable margin is wise, there is a very fast approached point where just having a generator would be a heap more economical even if you did have to pay for fuel. It would of course depend on where you were and the cloudless/ windless days you have per year on average and what generation you had installed. You can run a Lister or even one of the China horozontal clones Damn cheap ( and cheaper still on waste oil) and get a good amount of power very cheap. CS style lister will do about 3000w on about a litre of fuel an hour. Given the low consumption people here are claiming per day, wouldn't take a lot of hours running to charge the batteries and provide addition instant power either. Just bought a 12/2 with a 6 KW head for $1300 new. Bought a 6HP china Horizontal ( which I think in many ways is better than the Lister) for $150 used but bugger all work. You can get spares for both cheap and they have really good, low maintence service lives. Seems to me putting on a few days capacity gets to be real exy real fast and the cost of running a generator maybe 14? days a year on average would lower the initial system investment price a lot. Of course the other benefit with a genny is if you want to do high load stuff you can fire it up and run off that and not even touch the battery's reserve or tax your solar/ wind/ Hydro generation. Off gridders have Genny but just appears to me many don't factor them in much or use them except as a last resort when bringing them in to play earlier would be a better option. |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
I dont know, as many have done, having flatter panels works well in overcast conditions, and for offgrid, panels are so cheap (esp 2ndhand) its easier just to put in more panels if you have the room (and face it, most offgridders have tons of ground room to fit panel racks around the place) I found on the panels I use for camping that having them flat on the roof of the exploder didnt make that much less in sunny conditions, but increased the output markedly in overcast conditions to having them tilted, so much so that I stopped tacking the racks off so I could tilt them when camping, just wasnt worth it, esp in overcast Almost every place that is offgrid I have done or visited, has a genny as well, but the biggest complaint is 'too bloody noisy'- I have quietened my own down by removing the original muffler and screwed in a pipe into the original fitting thats welded into a car muffler, that helps, putting it in a shed with bessa blocks walls also helps, but esp at night, nope, no genny for me, hate that- its pretty much the last resort |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Solar is silent and does not smell, doesn't need oil changes, etc etc. Why would you want to start a generator but there certainly is a point where it is far more economical to start a generator. You don't need an old cast iron machine that is designed to run forever either. If it is only used 10 or so days a year for a couple hours a cheaper petrol one will do the job perfectly well. If it did 50 hours in a year that's 500 hours over 10 years, a cheap chinese job will last that long. 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 |
Exactly what I was thinking, my families needs are pretty small, so having 7.5kw of solar 800ah @48v battery and a backup dc petrol charger is really a great all round solution for Melb weather. I have good AM and PM access to sun, no trees till almost sunset. We often have cool days but with partial sun, sometimes full cloud cover. It will be very interesting indeed when the changeover switch is fitted the battery bank comes and the ozinverter comes online, I'm really excited about how it will turn out. EDIT, I think having a completely renewable off grid system is potentially uneconomical, depending on sun etc. many many factors there. I don't have any issue with backup dc gen, in fact that was my first thought when considering off grid. Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
I find on really dark rainy days I get about 10% of the power I would get if there was full sun. With my 9.5KW of panels I get a full charge if it is overcast so long as the clouds are not black. Even on the worst days, it is rare to draw down any further during the day. 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 |
That's interesting Madness, what do you estimate you would pull on a cloudy day (not hot and no AC) Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Cloudy is a very variable condition, thin high level cloud has near 0 effect, had a really think thunderstorm at noon one day and total power output was down to 35 watts. If it is big white fluffy clouds with some blue sky or complete white cloud cover we still get plenty of solar power. As I am in Qld and you are in Melbourne it may be difficult to compare, winter here is normally cloud free blue skies while you have gray miserable skies and shorter daylight hours in winter. In those conditions, you are most likely going to be having less SOC at sundown than you did at dawn. 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 |
Gennys can be very quiet or very loud, depending on what you have and how you set them up. This is a nice Quiet one: https://www.youtube.com/watch?v=B2682AwYJ7w A mistake a lot of people make is trying to quiet the exhaust when it's the induction making the noise. Both the listers and the China horizontals are notable for intake racket. Cars can be too. There is a reason a lot of them have all that induction plastic piping with weird little offshoots that go no where, it's about resonance and silencing. I have a car muffler on my lister as well as an intake box and it's got no bark at all. Mechanical clatter, for sure but no intake or exhaust Noise. My daughter is having her 21st next weekend and wants it to be a bush Dance theme. One of the main props or decorations will be the lister. Going to have it running powering some lights. My wife said about the noise and straight away my Daughter said no one will hear anything over the people talking let alone the music. My china diesel is literally louder with no intake than it is with now exhaust. Even with the muffler on, open the air box and the noise goes up a huge amount. I get that solar is easier, lower maintence, quieter etc than a genny. that's why I have panels on the shed that has about 15 engines/ gennys in it BUT, I also know that the genny give me full power anytime I need it whatever the time of day or night in any weather. One can get some very good and inexpensive Chinese stuff now but the trade off tends to be in things like noise. Again, usually it's NOT the exhaust, it's the intake that makes the racket. You can work with and around that too and get most of them very quiet. If I were going to do a petrol Genny I needed to be quiet, I'd use the engine off my Honda Mower. Twin Cylinder, water cooled, 13HP. My god that thing is quiet! And smooth running. I bought this mower used ( and about 30 years old) just for a fill in when I moved here. Now I want another mower because this thing is way too good for what I ask of it. Don't start it for a month. Turn on the ignition and wait till the fuel pump stops so you know it's primed. Push throttle to choke position, Flick key and pull throttle straight back because it will fire first compression stroke every time. Amazing little engine. I could never have one of those horrid Briggs powered things again after this little gold nugget Like everything they both have their upsides and drawbacks but with a genny AND panels/ wind, you have ALL the bases covered at a lower cost than just relying on the renewables alone. :0) |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
I dont think anyone uses (or has suggested using) using panels alone, every offgrid I have seen has an alternate backup genny of some kind (for the first 3 months at my first offgrid house we had over a ton of extelecom batterys- and a prime mover..., which charged the batts once a week) The aim is to reduce the use of a genny to a minimum, some people have done that to the degree that the only time the gen is started is just to check its still running (which can be an issue with some motors, my old Honda HAD to be started once a week- do that and it would literally start first time, every time... leave it a month and you can guarantee a good five minutes of heaving away until it finally fired) The advent of the bigger inverters (I have a 12v 8kw blackjack in the ute for gawds sake) has reduced the need for starting a genny to 'do the big stuff'- in many cases the inverter has more capacity than the genpack, and batteys become the limiting factor. Many people actually have too much panels for their battery size, but with cheap panels, and overcast conditions dropping output, it becomes easier (and in many cases cheaper) to simply pick up some more panels and aim to get a full charge into the batts even in overcast conditions |
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| Homegrow47 Newbie  Joined: 17/08/2010 Location: AustraliaPosts: 31 |
If your inverter failed or something similar halted your PV system output, then a generator would be a nice temporary backup. edit : Just saw Boppa's post, Very interesting, I can certainly believe that. |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
Although most if not all offgridders have a backup genny, this is in no way indicative of its usage, having lived in many rural locations over the years, many rural properties that are ongrid also have gennies- and some use tham a lot more often than the offgridders had to One place I lived was on a spur line, a fault anywhere on a 30km long line that ran through forest, meant the entire spur lost power- When we had strong winds in summer, you often got a blackout a week, sometimes one a day,outages from a few minutes to several hours, 5 years there wore out a yamaha genny to the stage the motor was using more oil than petrol |
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| Homegrow47 Newbie Joined: 17/08/2010 Location: AustraliaPosts: 31 |
I live 10km from Sydney CBD, and its been many years since I can remember any blackout at all. I'd still prefer to live off grid in the country though. |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
The advantage there of course Homegrow47, is that in metro areas, they have multiple ways of rerouting, so if a feed drops for some reason (much less likely in the city anyway) then they can easily reroute from another feeder and get the power back online In a rural area, there may be only the one substation, with multiple spur feeders running from it in all directions- any fault anywhere on one spur is likely to kill the power to that entire spur, and often they can only find it by physically driving it looking for the damage- thats assuming that they actually have available staff there locally to do the repairs- a sore point at my previous house as they culled staff from the local depot, so any time they had a fault- it was a minimum hour blackout, simply because the nearest staffed depot was 100km away instead of only 15 km away |
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| Homegrow47 Newbie Joined: 17/08/2010 Location: AustraliaPosts: 31 |
I have lived here 20 years and the only blackout that lasted more than a few minutes was when a huge tree fell on the lines in my street. This pulled and damaged a pole in front of my house and they had to replace it. This happened on a Sunday and it was repaired by the next day (25 hours). I applied for some standard compensation of $100 or some such, which Energy Australia paid, no questions asked. So all good. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Wow, there must be ways to improve that, at $1500 plus that would give me major bill shock! There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Hoping so. Projected @ $1727.49 when it arrives, and I'm usually within a $$ or so. Should add that I run a Home Business/Office here with 2 Xeon Servers on 24/7, 4 NAS's & the couple of PC's & 2 laptops that don't ever shut down; Add another 100W+ for security DVR & Cams etc. 2 8kW split systems, one a multi-head (3 rooms); Try to use them as economically as possible; including burning around 100W removing the 55°C air from the ceiling cavity.  Am in the process of trying to pull it back with a Hybrid in certain areas. New learning curve for me; getting the best of what I have.  Phil. |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Those Xeon servers would be power hungry if they are anything like the one I had. It was a dual Xeon, with redundant power supplies. Noisy! It was given to me, and I understand why, I used it for a week and that was enough for me, scrapped for parts. PC wise, you could save a lot of power by buying a new fast energy efficient Pentium with lots of ram, then installing the other PC's as virtual machines on the one PC. My PC with 2 monitors draws about 200 watts under normal load, even less when the screen are turned off. Less PC's also mean less heat, so the air conditioning works less. I've installed a new 2.5kW split inverter air conditioner in my home office, and on Saturday it was 39c outside, 26c in my office, and with everything running as normal ( fridge, standby stuff, air conditioner, tv, and pc, I was drawing 800 to 1000 watts continuously for about 8 hours during the hottest part of the day. All up I would have used 10kWh to 12kWh for the day. Normally I'm around 5kWh to 8kWh. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
I have a computer sitting on my desk with a 6 core Xenon CPU, I rarely use it now due to power consumption, 300W plus at idle. My main PC these days is a I7 Ultrabook that will run 8 hours on its own battery, power consumption while running is > 20W, however I normally use it with a larger monitor. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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