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Forum Index : Solar : Inverter help please
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Don B Senior Member  Joined: 27/09/2008 Location: AustraliaPosts: 190 |
Hi Curiosity, If I understand your initial posts correctly, you are hoping to use an inverter to support your generator, or vice versa, for an isolated 240V AC household supply. Trying to connect a generator and an inverter to run simultaneously into a single 240V line is not a trivial exercise, and I refer you to Allan's comment in a previous post "The inverters I have had dealings with sample the incoming power for acceptable voltage and frequency before synchronizing to that power then they close the contactor." As this indicates, at the instant of connecting the two together, the voltages, frequencies, AND PHASE must all be matched up or else there will be an instantaneous overload of one, or both. Further, once connected together, their characteristics need to be reasonably matched so that they both contribute in proportion to their capacity to regulate the line voltage and frequency as the load changes. This applies to connecting any two or more AC generating sources together, be they generators or inverters. In a power station, this involves a good deal of equipment and operator expertise. A simpler solution is to run your appliances separately from either the generator or the inverter, depending on which source is more appropriate. You could also use a battery charger run off your generator to help keep your inverter batteries charged up. The most difficult exercise with your set up is starting things with a motor like your pump, or maybe a 240V AC refrigerator. Your generator might struggle to cope with the starting surge from these sorts of loads and, equally, so will an inverter. Incidentally, a claimed 5,000 Watt inverter that can run off a car cigarette lighter and fit in the glove box is just a con, and I expect that they have deliberately added an extra zero to the output as a come-on. With inverters,as with most things, you gets what you pays for, and you simply can't get high capacity from a small cheap box that plugs into a low capacity source like a cigarette lighter. Things that have a large power requirement for heating like, say, a large microwave oven, are also a problem for your set-up, and you would be better to stick to gas for all heating requirements. Not much help, I suppose, but at least it might save you from wasting money on something unsuitable for your needs. Regards Don B |
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| curiosity Newbie  Joined: 04/12/2011 Location: AustraliaPosts: 31 |
In reply Don B Thanks for your input. There seems to be allot of inverters these days claiming to be able to run either mains power or generator. I guess it's to try to make a more multi purpose type of inverter. It sounds like you are saying they wont work? I've been selling some farm stuff to put towards our system and we may actually be able to afford an "L" cheapo setup with inverter,wind generator and hopefully some more batteries (fingers crossed) The 5000w inverted is not mine. Just someone who decided to hijack my post instead of making their own. In the first page I stated "Now we have all the mod cons Fridge,hot water and stove are all gas". Heating is wood fire so we have all that covered Anyone seen one of these in action? http://www.ebay.com.au/itm/Wind-Turbine-Generator-Kit-3-5-KW -Max-3-0-KW-Rated-48V-60V-Opt-Aerogenerator-NEW-/15080907395 8?pt=LH_DefaultDomain_0&hash=item231cebd926#ht_2409wt_1396 |
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| Don B Senior Member Joined: 27/09/2008 Location: AustraliaPosts: 190 |
Hi Curiosity, I don't doubt that there are inverters that can synchronise themselves to a 240V line. This is what grid tie inverters, for one, are designed to do. They may also claim to work paralleled with a generator, but it would probably need to be a fairly large unit for reliable parallel operation under varying load conditions. The grid frequency and voltage are very stable. It is therefore relatively simple for a grid tie inverter to transfer power into the grid in a stable and reliable manner in this circumstance. A large generator would be less stable, but an inverter might be able to be paralleled satiafactorily. Your small generator is a different matter, as its frequency and voltage will change significantly with changes in load. The relative contributions of the generator and inverter together to changes in load in a changing frequency and voltage environment would be difficult to predict without a study of the individual characteristics of each. You might be able to get the combination to work satisfactorily, and it might even be worth a try, but I would not bet the farm on it. If you use a standard inverter (ie non grid tie) powering a separate 240V line for small loads such as lights and other things that you would like constant power availibility for, you would probably save money and have a more reliable system. Many standard inverters will have a standby function so that they draw minimal power only from your batteries if nothing is switched on. Regards Don B |
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| curiosity Newbie Joined: 04/12/2011 Location: AustraliaPosts: 31 |
I had a slight change of heart on the inverter and may go for this one. It can be grid tie or stand alone. http://www.ebay.com.au/itm/6000W-48v-Solar-pure-sine-wave-in verter-60a-battery-charger-LCD-transformer-/130577333676?pt= AU_Solar&hash=item1e6703fdac#ht_5845wt_905 With the generator in my last post and this controller http://www.ebay.com.au/itm/230764672429?ssPageName=STRK:MESI NDXX:IT&_trksid=p3984.m1424.l2649#ht_6454wt_1396 Got any advise on those? |
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| Don B Senior Member Joined: 27/09/2008 Location: AustraliaPosts: 190 |
Hi Curiosity, The 6 kW sine wave inverter looks very suitable for your purposes, however, from the diagram that they supply, it does not appear to be a grid tie type - merely an inverter with lots of grunt and a built in battery charger (to charge from the grid or your generator), plus a solar panel charge controller. With an inverter set up of that capacity, then you might well be able to run all of your household loads directly off the inverter, and use your generator only to boost your batteries when the solar panels can't keep up. Do keep your batteries well charged though - particularly after you have drawn them down. The inverter's green mode should also help minimise battery draw when there is no household load. If you have not already purchased a wind generator, then I would hold off on this and the controller until you see how the generator/inverter/solar panel/battery arrangement works. Before buying the wind generator, you might also give consideration to more solar panels instead, unless you happen to have a particularly windy location. Wind generators rated at 1.5 kW (or any rating really) don't achieve anything like that output on a long term basis unless you have a true roaring forties exposure. Regards Don B |
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| curiosity Newbie Joined: 04/12/2011 Location: AustraliaPosts: 31 |
Grid tie is no good to me anyway as it's $70,000 just to get the line to run to the gate. The area is Edenhope Victoria. It's renown for cold, overcast and wind. So I wasn't planning on having many panels at all but I could be totally wrong in my thinking. Here is the averages http://www.energymatters.com.au/index.php?main_page=performa nce&climate=522425598&town=Edenhope&state=VIC&country=Austra lia&solarpanel=734 Allot of days you get over 20km/h winds for most of the day. Some days would be no wind obviously and others are 100km/h (battern down the hatches)LOL |
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yahoo2 Guru  Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
If you could match those watt hour numbers from the energy matters I would have a solar system at your location yesterday. I would find someone that has roughly the same cloud/fog as you with a grid system and get some stats from them. You might be pleasantly surprised. (the reason I say look at someones grid system is cos with a battery system the power generated is throttled back as the batteries are charged so it wont give a true power reading for the day/month.) I'm confused, no wait... maybe I'm not... |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
Curiosity, OK I will be the one to say it! this thread has gone to 4 pages, you asked a valid question and received answers, you are fast entering the we won't listen territory. Cheep equipment is cheep equipment, some may last a life time most won't, sorry to be the one to tell you this but a good quality OZ made grid interactive (grid can mean owners generator) inverter of the KW you are looking at costs $10,000. What you want is someone to advise/tell you to take a certain rout, so if it does not work "it's not my fault". Unless you live somewhere like Flinders Island you can never rely on obtaining more than 15% of a wind turbines rated output, on the average. Solar panels have come a long way, I live in Far North Queensland, all my research said solar does not work here. I installed 10KW of solar to allow for cloud cover, just like now when through clouds, although thin I am receiving 3.96 KW of solar. Just my take on this thread. Have a look and listen here daintree to you want gas (im the agent, Bob waffles on about things, he is 5 blocks up stream of me, a bit frightening actually) Sorry Bob but it is the truth. Allan of the Daintree "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
I just had a look at a 5Kw system in a spot that has a reputation for cold and wet, they are on track for 7900 Kw for this financial year. That is an average of 4.36 watt hours of power per rated watt of panel every day. Not to shabby at all. I'm confused, no wait... maybe I'm not... |
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| curiosity Newbie Joined: 04/12/2011 Location: AustraliaPosts: 31 |
 I'm certainly not looking to blame anyone for anything. I am simply trying to fully understand something I have no knowledge of. It is however puzzling that a wind forum would discourage wind power, even in the solar section.
I don't have anywhere near 10k to spend on the project, little own an inverter so I guess I should just give it up as a pipe dream. I've obviously gone way to far already with my thread and have appreciated any comments that members have put forward (especially you Allan) Ive asked the mods to lock this thread so it will no longer annoy |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
I doubt Glenn will lock this thread, no board rules have been broken, and you are not annoying me. Call it tough love if you will, personally I am just trying to say it as it is. I would never deliberately discourage anybody from having a wind turbine, had a few myself in a past life, just understand the realities of the potential output. Looking back wind has played a very important part in Australia's history but our expectations have changed. There are very few places in Australia where wind alone can provide sufficient power for a modern household. Wind can and does make a contribution, just look at the number of commercial wind farms, but alone they provide only a small percentage of our grid power. My last comment was a bit rough, so I apologize to you for that and will step back into the corner. Grumpy Allan "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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