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Forum Index : Electronics : SImplest way to use a GTI in stand-alone mode
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| rogerdw Guru  Joined: 22/10/2019 Location: AustraliaPosts: 852 |
Hi guys, I came across the forum while researching how to use a second hand GTI and panels in a stand-alone circuit … to run our pool pumps. Since last Fri I’ve spent ~ 20 hours reading as much as I can … and while I’ve learned a lot … I wonder if anyone can put me straight as to the easiest/simplest and cheapest way to achieve my goal. Thank you for any help. Cheers, Roger Cheers, Roger |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Hi Roger, welcome to the Forum. As you will already know, a grid tie inverter only works when it is connected to the grid (or thinks it is connected to the grid). They cannot be run as just a stand alone inverter. You may be able to run a lower powered grid tie inverter when connected up to another more powerful inverter that is fed from a battery, but that is neither cheap or simple and is fraught with problems. If you get that far, its simpler just to use the larger battery powered inverter without the grid tie inverter, and use the solar panels to recharge the battery, as in a normal straightforward off grid installation. Sorry Roger, but what you are asking cannot be done. Cheers, Tony. |
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renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
There is a reason they are called Grid tied. I asked the same thing a while ago here Cheers Caveman Mark Off grid eastern Melb |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
One idea that has just come to mind, might be to fit a universal ac/dc brush type motor to your spa pump so you can run that direct off solar. It might not be all that difficult to do. Remove the fan housing and plastic fan from the rear end of the original induction motor and fit a pulley in place of the fan. Then belt drive that from a suitably powerful ac/dc motor. Without the fan, the original motor can no longer be safely run from grid power without destructive overheating. But it should still work great as a pump when belt driven by a second motor that has its own cooling fan. The beauty of this is that an ac/dc motor can be run either off the grid, or from 230v nominal dc from solar, with just a simple changeover switch. If you want to be really sneaky, this power changeover might eventually be automated. Cheers, Tony. |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852 |
Thanks for the welcome and the links ... another couple hours of research.  Okay. Had a feeling it was going to be something like that ... but had to ask. So a self made Oz/Mad/Warp inverter ... and a set of forklift batteries ... say 1000Ahr @ 48V If that is correct ... what sort of battery charge/control system would you use in that case? Thanks Tony and Mark. Cheers, Roger Cheers, Roger |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852 |
That's a great idea, had certainly not thought of that. I had looked into a variable speed pool pump that is supposed to be so much more efficient. I had wondered if they run on dc ... whether I could build a device to supply one direct from the panels ... and forego an inverter altogether ... ... but they are so expensive, I'm having trouble with that idea. Our place has no solar at all yet, so I really need to address that. It's been the advent of summer and endless hours of pool pump running that has woken me up to the fact that I need to take some sort of action ... sooner rather than later. Cheers, Roger Cheers, Roger |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Basically you need to size the individual components of the system to suit the job at hand. Inverter rated power is pretty self explanatory. Battery sizing is something else. The battery will be the most expensive part of the system, so you need to think in terms of how many hours running time without sun. In mid winter (Melbourne) that might be seventeen hours running off battery, and potentially seven hours of solar. But it can sometimes go evil grey sky for two or three days in a row. I am told its even worse in Sydney. Sizing a battery for several days total backup is just not economically viable just to cover two or three really bad patches in mid winter. So you can get away with much less battery if you have an alternative to solar recharging. Either a generator or the grid perhaps when its really bad. As a rough estimate, a battery size in Kilowatt hours equal to your daily consumption might be about right to start with. That should work quite well, but will run short on power maybe two or three times only in mid winter. Bear in mind that the battery only has to supply night time power, highest loads will be throughout the day, and that will come direct from solar most of the time. Example: Total daily mid winter load 6Kwh from historic power bills. 3Kw hours over seven hours during the day, 3Kw at night over seventeen hour period. 6Kw of solar panels that in theory could replenish 24Hrs worth of power in only one hour in a clear blue sky. A 6Kw hour battery that will easily handle the 3Kwh night time load, but may struggle if you ever have a zero solar day. For recharging you are going to need some solar panels and a commercial solar controller. Plenty of choices there, and it should not be too difficult to find something with appropriate voltage and current ratings. You first need to do a power audit to get some idea of the loads you will be dealing with, particularly through mid winter. That is also a great opportunity to replace some wasteful power hogging appliances with something more modern and power efficient. Its always cheaper to replace a few ancient appliances and reduce the daily load, than to build a more powerful system to cope with what you have. So basically do the power audit, maybe use some historic power bills as a basis. If you use X Kwh per day. Start thinking in terms of X Kwh of battery capacity as a minimum, and X Kw of solar capacity. That should get you a workable system, that may not be exactly optimum, but should come close, and be a good starting point. Cheers, Tony. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Some further thinking about this. How about a 2.5Hp treadmill motor ? The big ones are usually 180 volts dc and around ten amps, and most run at around 4,500 rpm full load. Possibly $120 on e-bay secondhand. Six 24v 250 watt solar panels (that are really 30v) in series might be about right for that. With a suitable speed step down pulley ratio driving the original pump, that should be able pump plenty of water. If you fitted an external cooling fan to cool the original pump motor, that should remain usable off mains power. Edited 2019-10-23 15:00 by Warpspeed Cheers, Tony. |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852 |
Cheers, Roger |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852 |
That is a great idea. In fact I occasionally see treadmills for cheap or giveaway on our local buy, swap and sell pages. I could swipe the motor out of my wife's treadmill ... she wouldn't notice ... she doesn't use it anymore.  Cheers, Roger Cheers, Roger |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Probably the very first step is to do a complete power audit. Know how much power each appliance uses each 24 hours. There are going to be some real eye popping revelations. Something like this perhaps, available from e-bay and retail stores:  I managed to reduce my power consumption to just less than half, without changing my usage or lifestyle. Just a very few examples. I had two electric wall clocks that each consumed 15 continuous watts. That is 30 watts x 24 hours = 0.72 Kilowatt hours every single day. Those went into the wheelie bin and were replaced with a pair of battery wall clocks that run off a single AA battery that lasts one year. Led lighting everywhere, replaced numerous fluorescent and incandescent light bulbs, with a massive power reduction. A new (secondhand) refrigerator replaced the thirty year old dinosaur. An F&P washing machine that does a full load and only uses about 85 watt hours to do it. Replaced my old CRT computer monitor with flat screen LCD monitor (this was quite a few years back). No longer use an electric jug, but boil water on the gas stove which is actually faster. Many more things, such as a laptop computer always plugged in to keep the battery alive drew 17 continuous watts. A plug in time clock in the mains plug turned on the laptop for half an hour four times every 24 hours. It all sounds pretty trivial, but at the end of the day I better than halved my power consumption for minimal cost. Payback worked out to about two and a half years if I had stayed on grid. If you become really fanatical, and keep nibbling away at the problem, truly awesome cost savings are possible. I now use typically 4-6Kwh per day whereas it used to be more like 9-12 Kwh per day. Its fortunate that I have natural gas here which can be used for cooking, room heating, and hot water. Cheers, Tony. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
If you want to stay connected to the grid you may be better getting a grid tied system. No batteries to worry about, panels power the pump during the day and you put in credits for the power that you don't use. Generally people that use a fair amount of power during the day do better with grid tied. Just sign the paperwork and let some other bastard do all the work. If the GTI stuffs up down the track, re configure the series parallel connections and go off grid then if inclined, or get another GTI. Edited 2019-10-23 20:05 by renewableMark Cheers Caveman Mark Off grid eastern Melb |
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| Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814 |
Don't even need to reconfigure the panels these days, there are quite a few offgrid inverters going the HV panel voltage route This is one example of these kind of inverters (can run as gridtie, gridtie with battery backup, or straight battery power)  MPPT ranges 120V~450V, Voc 500V Input / Output Voltage DC 48V / AC 220V~240V Plus you can parallel them as well to get more capacity  Not recommending this particular brand or anything, just that they are certainly out there... |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
To Summarise a reply to a lot of what has been said and the original question which was running pool pumps. You wouldn't need a very big battery pack at all. If you had plenty of panels which are cheap to buy these days, all you really need batteries for with a Non GTI is for " Ballast". Pool pumps don't need to be run 24/7. Generally 6 Hours a day in swimming season is enough but if you were using solar you could go as long as you liked. I buy used Panels for $15 to $25 each now. If you pool pump is 2 Kw you could go overkill and put up say 4 Kw of panels. That would cost about $400. Put them to a suitable charge controller and you can run the inverter from that and the batteries will virtually not be touched except for the odd cloud. Set the cut off on the inverter high so the batteries arent discharge much. Sun comes out, things start working and off you go again. If you have a chlorinator the lower sun will mean less UV and less time the clorinator needs to run. If you are still using Chlorine then you are only cleaning and what you miss today can be made up tomorrow. As far as winter goes, What I did was get some thick Builders plastic to cover the pool with. I had to weld it together because it was only 4M wide and my Pool was 6Mx12. Yeah, was a pool to behold. Covering the pool menat all the crap stayed out and I Only ran the filter once a week or so when I remembered on the weekend. Because the sun couldn't get to the water, the chlorine ( salt water pool) stayed way high and so there was no algae. The rain water puddled on top of the plastic and didn't dilute the pool water either and I just pumped it off. Of course all the dirt and leaves stayed out as well. When swim time cam, I'd remove the cover, see how sky high the chlorine levels were, Do the regular Ph adjustments and let the creepy crawly do it's rounds to pick up the dust and crap that had settled out of the water. Pool was ready to go in an hour really. I well overlapped the plastic over the edge coping and just held it in place with Bricks and lengths of heavy form work type timber to hold and virtually seal it in place. The plastic can be had at bunnings for about $100 a 50M roll or cheaper at plastic suppliers which is where I got mine. I Welded it together with a Soldering Iron and even though I thought that would be dodgy, it worked good as welding metal. If the plastic ripped it was NEVER where it was joined. Beauty of the black cover is it's a 100% coverage heater. DON'T leave it on in the middle of summer. I did once as I wasn't using the pool and friends came over and wanted to have a swim. The Pool after the pump had run and mixed the water was a full 40 oC!! Mate went into the laundry and threw a cake of soap in the pool. I said what's that for? He said well everyone needs soap when they are having a bath! It was a pretty warm bath at that! Personally I wouldn't muck around with an inverter and batteries. I would ( and do) just get a GTI and panels and plug it into the mains power point. As long as the inverter is under 3KW You are fine. The GTI will power the circuit and offset your usage up to it's capacity. If you are fortunate enough to have an old spinny meter, any excess will spin it backwards. If you have a Smart arse meter you would have to see how that is set up and if you can't send excess power back, get a non export meter or a diverter that send the extra power to your hot water system. I set up my own bootleg system and was pushing back 12Kw for over 5 Hours today and am regularly generating 70-80 KWH a day over the last few weeks. Solar is very easy to set up, there is no magic to it but doing it from used components give a payback time of months not years. As for taking your whole house off grid, still going to be more expensive than staying on the grid over the long haul. If you offset your grid use with solar ( without batteries) then you have the cheapest power you will get. The second you go to batteries you are behind the 8 ball. Forklift batteries are the best value I can find but still, going to be $3-4K you have to make up straight off the batt plus inverter/ charger and all the associated and never ending wiring, connectors, monitors and so on. I completely agree with Tony in saying to work out how much power you are using. That pool pump may seem exy to run, right up till the time you figure how much money you will need to spend to off set it and how long that investment will take to recover... If you even can. Best way is with a DIY solar system using a GTI. Batteries... I doubt it's possible to even get your investment costs back let alone be ahead. Time you catch up, the batteries will need replacement and an inverter or charge controller, or both, has probably already needed replacing. Myself, I rather pay a smaller amount regularly than have a big hit all at once. If you have the money in the back, great but it's spending it on a boring long term investment and if you have to borrow, well that's going to draw the repayment period out even further. Know what it is costing you before you spend lots more money You'll never get back trying to save a fraction of the cost of offsetting the expense. |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852 |
I'm not saying I want to be consuming power from the grid ... but it makes a ideal back-up if I were to build a system and it happened to blow up. The grid simply buys me time till I fix the system. I do see your point about just paying the money and getting a stock standard system and carry on. I understand I can get a 5kW inverter with 6.6kW of panels for between $3,500 - $4,500. Certainly it will make a dent in our grid usage and with a bit of retraining for us ... and the fact there's only 3 of us here now, not 5 ... should make quite a difference. Especailly 2 less teenage girls!!! Tony is right in saying we need to work out our usage now ... before we can make a decision I guess. Cheers, Roger |
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| rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 852 |
Mmmm ... I was reading a thread where warpspeed mentioned he was designing an inverter that ran soley on panels ... no grid tie or batteries. How did that pan out? I wouldn't be averse to putting up a heap of extra panels ... seperate to a grid tie system ... to do that. Wow ... I wish I could find them for that price. We have a couple of huge sheds ... one with north facing roof ... 4.5 mtrs x 24 mtrs. Would fit enough on there I'm sure. Sounds like a great idea. I saw a truck tarp being sold locally a while ago ... and it crossed my mind then, that it would make a great pool cover for winter. I may have to copy your idea. We do have a solar cover ... but the crap still gets in around the edges. But doesn't that raise alarm bells. I'm all for pushing the envelope ... but I'm not that game.  Certainly keen to get a heap of extra power generated ... but for me, I'd only be comfortable if it was stand-alone ... with no connection to any legit part of our system. I'm inclined to agree with you ... though a 5kW grid tie system is going to cost me that much and more anyway. I hate to have to admit it ... but our first year here in this house we paid close to $5k in power bills. Our very first (quarterly) one was over $1,300. Our latest was around $600 ... but x 4 is still $2,400 for a whole year. Yep ... weighing it all up. Another sleepless night tossing ideas around. Thanks for your input. Cheers, Roger Cheers, Roger |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
What I did was design myself an inverter that would operate over an unusually wide dc input voltage. Most inverters are used with batteries that have a much more limited voltage operating window between peak charging voltage, and minimum dc voltage at full battery discharge. The idea behind that was so that my inverter would operate straight off solar panels during the day without requiring a battery. At dusk, or in awful weather, the voltage would fall low enough for a grid powered dc rectifier to supply dc power to the inverter. During the day, provided there was sufficient sun, I could run completely from solar. Any deficit was drawn from the grid. At night all the power came from the grid. Changeover at dawn and dusk was smooth and seamless. I ran like that for about eighteen months. The overall result was that in summer about 80% of my power came from solar, and in mid winter about 55% came from solar. Extra solar panels would not have helped those figures very much because there is nothing to be gained at night, and any extra available power during the day that is not used is of no value either. Its only on marginal days that extra panels help, and the point of diminishing returns kick in. As secondhand panels become cheaper, I may keep adding some extra, but they would need to be very low cost panels to be worth the trouble. Grid tie is a bit of a mixed blessing. The power utilities will keep moving the goal posts to ensure that they have enough revenue to maintain the distribution system and stay in business. The more people that go grid tie, the lower the feed in tariff and the more they keep tightening up the rules. There is also the problem of power blackouts. As you are situated a fair distance from Adelaide, bush fires and other problems might leave you without power for extended periods, and a grid tie system shuts down when the grid shuts down, unless you have one of the latest battery backed grid tie systems. So all things considered, a grid tie may not produce the long term financial benefits many people hoped for originally, as the buggers keep changing the rules. Grid tie may still be worth looking into as part of a much broader overall plan, but its not really some kind of ultimate solution for either us or the power utilities. Cheers, Tony. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
You have two paths to choose. 1. Easy path, get a grid connected system that will cover your pool energy during the day and give you power, excess goes to grid. You are limited in the max size here. 2. Build your own system as big as you want. Unless you are a sparky you can't (in Vic) wire anything over 120v dc. So you need to do multiple strings of 3 for mppt controller, or two for a pwm (running a 48v batt). That's a LOT of wire and a LOT of work. You'll be lucky to get a decent fork battery (800ah or so) for under 4-5k. Sourcing panels second hand in Vic and SA is a hell of a lot dearer than up the coast where they have been big users for a long time and lots of systems are continually upgraded, providing the area with cheap panels. If you plan to build an inverter yourself, how experienced at electronics are you? It's not an easy job to build one, even Poida and Madness have had multiple blow ups, I have had a lot more than most due to my lack of experience. If you plan to build one you'll need 2x 3kw torroids to start with and they are like hens teeth these days. Making the transformer is a pain in the ass itself. If you can't find suitable torroids to rewind you'll need to get a transformer made, probably $2k maybe more.... dunno. Off grid system with a battery you could EASILY spend $10-12 minimum if you do most of it yourself. That's for something like mine that is self sufficient with 11kw of panels. Cheers Caveman Mark Off grid eastern Melb |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Its REALLY difficult to in the end come out financially better off no matter what you do. The key to this is reducing your total power consumption. Grid power is the cheapest power you will ever have. As you go through the interesting process of measuring the actual power usage of every appliance, you will discover that its not the really big short term loads that are costing you. Its the small things that run continuously for 24 hours that really add up. Cheers, Tony. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
My Nephew has designed and sold a controller that runs Direct off panels or with battery backup. He's sold a ton of them to some Asian Gubbermints to bring light and power to remote Villages. They are only doing 1.2KW atm although I believe they are working on a 2 Kw version. Hoping to get a couple off him to test/ play with. You have to look and not be afraid to negotiate. I haven't bought any where they advertised them for that price but wheeling and dealing is half the fun. With 250W panels, That would give you 12KW. Should be adequate. That's why I mentioned it! :0) It does work really well and is cheap and simple. Proper pool covers might have a few refinements but are way over priced. Been Fine so far. Everything I could find and people I talked to in the power game all said the only thing they look for is really HIGH bills to see if you are growing an Illegal Crop. My only concern now is that the Police Choppers that use the local airport 1.5 KM away will see all the panels I have and still think that's what I'm doing! Ah well, nothing to hide. If they pay me a visit they will just see I'm a Nut case not a career benefiting case. The other thing I have been told and take with a grain of salt is they measure the power going into an area and if it's higher than what they are billing, they might start looking. I can't see that being practical but in any case, I'm not stealing power and the usage here would be all over the place anyway. One neighbour has solar and goes away a lot, sometimes for a couple of months so their bills are lower than I'm game to make mine. Other side are either not there or the family come for a few weeks and they must burn power like no tomorrow. Neighbours across the street have Kids living in the granny flat out the back and have a Pool so probably paying $1500 a quarter. There is no way they could have an average bill round here or a lot of places I reckon. I am careful not to go backwards on the last bill. That would ring alarm bells for sure. I let the solar take the meters back with about 50-100Kwh useage on each phase when they are read and turn the solar off when the meter reader comes. He came early first reading this year and I got lucky that one meter was the same as the last reading. I'd switched the solar off to rack up some more useage but wasn't expecting him for another 2 days when I would have had more useage racked up. That's not unusual to have the same reading though. 1 Leg only has the 3rd phase for my AC connected and I haven't used that in months being neither hot or that cold. Few nights we have been cool we just used fan heaters which I have the power circuits on the backfed meters so the 3rd phase is still the same and may well be for this whole quarter legitimately. Unfortunately that is an electronic meter that registers all power as a usage so I can't rewind that. Most annoying but I'll take the opportunities I have and give thanks for them. My solar obsession has saved us a LOT of money and allows me a peace of Mind I am VERY grateful for. I do have another small Inverter I hook up in summer that is controlled by the AC through a relay. When the Compressor Kicks in, the inverter fires up and power's the compressor. Depending on the time of day, this offsets about 90% of what that leg uses so makes running the AC very cheap. Not a concern I have. All my GTI's are used equipment that was OEM and Compliant. Far as I'm concerned, what's behind that is of No consequence to the grid. I had a solicitor mate have a look at the rules and regs and his summation was what I am doing is not illegal because I'm not stealing power nor interfering with other customers or the grid safety, It's just I'm doing something they probably haven't thought of to make against their regs yet. There is definitely a risk but I gauge it and the possible consequences to be extremely low and something I'll accept. Far as I can see, even if I do get caught, there is little they can do except make me stop and install a Smartarse meter. I have left roof space on the north side of the house roof to have a legit system installed. I'll have a 10KW connection approved which I can have being on 3 phase and then I'll hook my inverters back up again so I can rack up a load of FIT to offset their rip off 6/8C they pay for the power you make. It may be possible to get a nill bill over the course of the year if I can do that. Don't even get me started on how corrupt and mis managed the power co's are. They can't even get the supply within 10V of what it should be here. I don't worry about doing the right thing by those whom want to screw me (and everyone else) over at every opportunity but each to their own. They want to charge my mate up the road $34,000 to put a new transformer in the street to allow him to be able to draw the amount of power he is entitled to but they won't connect because their old equipment won't handle it. He said fine as long as I am the ONLY One connected to it given you want me to pay for it. Of course they wanted him to pay but they would connect everyone else in the street as well. Unbelievable. He has spoken to the neighbours a couple whom have also asked for a higher amp connection and been knocked back and they are all going to organise a time where they all Turn everything on they have and blow the snot out of the transformer as they have been told it's way under rated anyway so it has to be replaced at the power co's expense.... as it should have been years ago. Yes but you will get that investment back. Batteries will always be an ongoing cost. The other thing is if you are running heavy loads like a pool pump and AC you will have to manage your consumption. Not something you really have to worry about with the grid. The other thing is the BATTERIES will cost you $3-4K. The REST of the system will probably cost you another 5-10K and you'll be up for a good amount when you average replacement costs of wear and tear on equipment anyway. If your batteries cost say $4k and last 10 years, that's 400 a year. If an inverter costs $2k and lasts the same, that's another 200 a year. Not hard on a big system to get to a grand a year and that's if you don't have any unexpected failures. OTOH, a solar system may cost $4k and be paid back in 3 years and then you are in front every year. If you are a big user, a 10Kw system may be better. Cost more up front but will repay quickly and the savings then on will be more substantial. You have to crunch the numbers that apply to YOUR situation and see what works best for your needs. I know where you are coming from. The guilt trip because your Bills are not what everyone else has. Mine were the same, Only worse. Round here, it's not uncommon for people to have $1200 -1500 power bills and more. The houses are large, we are running our own septic systems with pumps going all the time, The weather is very cold in winter, 40o+ for a week at a time in summer and there is no town gas. My brother in law round the corner has a summer bill of $1800 to $2k with the air and pool filter. I'd guarantee the Dr. up the road leaves that for dead with his mansion with the pool and tennis court that's lit up more nights that not in the warmer weather. The lights around the house going all night every night which look beautiful probably add up to a few kwh a night even if they are all LED which I am sure they are not. Won't be long and he'll have his Christmas lights up which would put the Griswalds house to shame. Good on him. Puts a smile on a LOT of peoples faces and I'm sure he works hard to pay for it all. It's nice to see cars cruising the street with the little kids hanging out the window looking at all the houses that put lights up round here. Lots of people quote low bills and shock and horror at anyone using over 20KWh a day but when you get into details, they have gas hot water, cooking and maybe heating or they have a wood stove in winter. They might also live in mild climate where they boast they use AC less than 10 days a year in total. They will tell you they use $200 a quarter in power but never their what they pay for gas and costs for Fire wood. For those of us that are fully electric, there is no comparison. Nothing for me in winter or summer to burn through 50-60 Kwh a day with the AC. That's why I have a stack of panels. Last year some do gooders on another forum were lambasting me for " Blasting my whole house with AC" and putting a drain on the stretched grid when they were asking people to back off their AC. I pointed out to the ignorant green obsessed that while running my AC, I was still pumping more than 5Kw back into the grid supporting my neighbours use and propping the mismanaged grid up and doing it a favour. My AC pulls 1500W off 2 phases and about 1900 off the 3rd for about 5KW all up. Yesterday I was pumping 12Kw back to the grid and I'm not finished with my setup yet. I'll be doing the power company Bastards a bigger favour again this summer. I'm looking for a 1500W inverter for the 3rd leg of the AC. I had the main leg on the electronic meter last year with a 2Kw inverter but I rotated the phases so it's on a backfed leg now and I need a smaller inverter for the non offset leg. I actually find it all quite fun and a good brain exercise. That said, Often I'll think something through for a week and 10 Min after I have done it, I'll see the realisation of how I SHOULD have done it but completely missed the glaringly obvious which now smacks me in the face! :0( If you have the independence bug and want to save some money, a real easy way to apply solar is with your hot water. You can easily set up a system to heat your water with panels that is not grid connected that will supply your hot water most if not all the year. Few ways of doing it, one would be a separate feeder tank that goes into your regular heater. The first heater is solar powered and if it heats the water enough the main heater never kicks in. If it does not get the water all the way up to temp, the main heater finishes it off and you save your bill on what it would have cost otherwise. Again, a number crunching exercise to see how much the hot water is costing you, what it would cost to eliminate that bill and the payback time. I find plenty of good used heaters at the junk yard that may just need an element or a thermostat or have nothing wrong with them at all and were just replaced because someone put in gas or made the mistake of going solar Direct. Whatever you do, Don't pay more than $50 for a used 250W panel. People ask stupid prices all the time but a month later, most but definitely not all, realise their overly optimistic pricing and come down to reality. I set my price point at $100Kw But that is for good 250W panels. I bought the last lot for $25 ea and for older 190's etc which are very plentiful, I'd not pay more than $20 ea for them. Prices vary in different areas, I have seen them a lot cheaper in QLD but again, DON'T pay too much and don't take the advertised price which is inevitably over what the things are worth. |
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