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Forum Index : Solar : Cheap Off The Shelf Inverter
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| ryanm Senior Member  Joined: 25/09/2015 Location: AustraliaPosts: 202 |
Hi All, I've got some PCBs and a whole box of Aliexpress componenets waiting for me in a box, but not enough time to put them together at the moment. Had a whole lot of short (less than 5 seconds) blackouts with the current storms about and I'm looking at getting a small hybrid inverter to keep my fridge and TV running until I can get properly set up with a home made one. Was wondering if anyone has had any good experiences? I'm currently looking at this unit from MPP Solar. Brand seems to have decent reviews on youtube and the company is actually registered in Australia and uses Paypal. |
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Revlac Guru  Joined: 31/12/2016 Location: AustraliaPosts: 1022 |
Hi, No experience with the 24v models, but have used the 48v models for years without much trouble. Is there any reason you can't go for a more powerful model (apart from the price) to give you some more headroom? If it could be the same system voltage as the ones you plan to build. Cheers Aaron Off The Grid |
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| ryanm Senior Member Joined: 25/09/2015 Location: AustraliaPosts: 202 |
Nope, just cheap. I also don't want to waste too much money on a big commercial unit when I've already got all the parts to make several monster DIY units. Four huge toroids sitting in the shed. For now I'm just going to hook up my brand new LG inverter linear compressor fridge, an LED batten and my smart TV. Peak power draw shouldn't be above 5-600W. On the batteries thought was to run 2S2P for the next few months at 24V, then swap over to 4S when I've got a bigger inverter. |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2135 |
For short outages I use a very cheap 600W 12V inverter from Aldi, $80 I think. It runs a conventional fridge, TV, computer, NBN modem and a few lights. When the battery voltage drops it has trouble starting the fridge. You probably wouldn't have that issue with an inverter fridge. The start surge on mine is over 3 amps, 0.4A running. |
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| ryanm Senior Member Joined: 25/09/2015 Location: AustraliaPosts: 202 |
Chasing a hybrid one that tops up from the grid automatically so I can keep it hooked in 24/7. Last night power flicked out for barely a second about 7 times. Every &%A#F* time I had to get up and turn my remoteless amplifier back on. |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2135 |
A small UPS would be all that is needed for that. Proper outages here, the last was two days and for four days a few months ago. Edited 2021-11-29 21:05 by phil99 |
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| ryanm Senior Member Joined: 25/09/2015 Location: AustraliaPosts: 202 |
Yeah, I run an IT business. Was running a UPS until the battery got buggered and I was too lazy to change it. Square wave though and I don't want to run my fridge off that if I can help it and a pure sine UPS is within spitting distance of the solar inverter with grid charging included. Also I want to run LiFePO4 and I don't know if you've seen the prices on those UPS units, but god damn... |
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| ryanm Senior Member Joined: 25/09/2015 Location: AustraliaPosts: 202 |
I also get 4-5 hour or overnight outages a couple of times over summer. One of the many benefits of being on a remote SWER line. |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2135 |
It may be worth getting a battery for your UPS. The modified square wave from your UPS is unlikely to be a problem for the fridge as the mains supply is simply rectified and filtered, after going through a choke for RFI suppression. If you want additional smoothing make a short extension lead with a large choke in series. The secondary (24V to 60v, 1A+) of a transformer should work. My inverter is modified square wave and has never caused any problems. Edited 2021-11-30 10:55 by phil99 |
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| ryanm Senior Member Joined: 25/09/2015 Location: AustraliaPosts: 202 |
The UPS will get a battery swap, but I'll use it in the office on a computer or sell it. I want to move towards a solar self consumption setup. Already got the panels so time to bite the bullet. |
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| Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 458 |
We had the same problem with unreliable network power.We live on a mountain in Tassie, I think the first 3 months of living here we had no power for about 5 or 6 days. Whenever wild winds blew the lines would go down somewhere. Having lived in Solar for nearly 40 years I was not aware that mains was that unreliable. Our solution was to get the power disconnected. Cut the poles down and enjoy the trees growing. We have very modest power usage but still get a lot of mountain fog and clouds. So far 5kw of panels and 660 amp hour 24 volt batteries are doing great. I upped our panels from 2kw to 5 kw and have not used a generator since. The cost of replacing private poles is ridiculous, stand alone power is much better for us. I have 4 inverters, one commercial 2.3kw inverter and 3 x 8010 based inverters with transformers from our old Powerjack inverters that kept blowing up. So far the 8010s are running great, nice clean sinewave and after a few adjustments they are doing what we want. We don't run any load bigger than 2400 watts though. Like I said we have pretty minimal power usage. Pete |
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| bob.steel Senior Member Joined: 27/02/2020 Location: AustraliaPosts: 188 |
Sounds like you are all set anyway . I have an MPPSolar hybrid 5 K running here with 12 off 250 watt panels putting out 300 to 350 v DC . That will run 20 amps of 240 v A/c out even without a battery attached in full sun. Cost me $1300. Works great. 3 years or so now I think. 48 volt. I attached 100 Ah of LFP to run basics overnight and that ran it down regularly but by geez the batteries were back up to 54v peak by 9 am. have recently upped that to 300 Ah because it all worked so well. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
12x 250= 3000W 20A@ 240V = 4800W If the inverter isn't connected to any batteries, could you explain where the other 1800W is coming from? Is it thin air or your Imagination? Moonbeams perhaps?  Wonder what panels you have? Every 250w I have seen puts out very close to 30V VMP and around 39 VOC so 12 Panels would be putting out a min of 360V unless you were dragging them off their curve at which point the wouldn't be putting out anywhere near the 250W rating. Of course then the is the small matter of the panels are never going to put out a constant 250W and the inverter is going to have about 10% losses so the reality of what you would get out of a setup like that is going to be at very and short lived best, about 2500W. That's a fair bit short of the 4800w You claim, 2300W short in fact, but hey!, If Bob says that's the way things are, well whom are we to believe Maths, reality and experience of everyone else over that "eh? This demonstrably flawed statement does seem to match up with the laughable claims you keep making about batteries and in line with the level of credibility you have established though. On other threads you have been repeatedly claiming that only a 1/4 of the capacity of LA is needed in Lipo because you can run them down so far but yet in practice, you run triple what you need to? A skeptical person might say that makes your claims hypocritical at best and stupid at worst. Frankly, I'm still trying to work out the statement you made and were questions on that running lipo batteries down to nothing was fine and didn't damage them but don't do it too often because it will damage them. But No worries, as you have also stated ( and then again done the complete opposite) You do not have time to be correcting and educating everyone and no one Drinks the Koolaide you keep leading them to so no need to reply. Your Credibility level is well established and Verified and much better you go share these sorts of claims else where because frankly, I think what you say is a complete load of crap. The simple maths backs that up. |
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| ryanm Senior Member Joined: 25/09/2015 Location: AustraliaPosts: 202 |
Some cabbage was too lazy to take these to the tip. Wouldn't even take money for them. What a steal. I'm told the GTI works so I'll give the homemade inverter a go so I can backfeed and avoid buying a charger. I was pretty gung-ho about the MPP unit, but when I read the manual I don't really like how the powe path topology is set up. From my understanding it powers the inverter directly off the solar and if the solar does not meet the load it will transfer to battery or grid. Some of my gear is sensitive to small power losses, even from an interactive UPS transfer. Also doesn't seem like you can use the inverter and charger at the same time. At night I would like to run off the inverter with the grid keeping my batteries from being too deeply discharged.  |
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| bob.steel Senior Member Joined: 27/02/2020 Location: AustraliaPosts: 188 |
Yes .They can't be legally used on GRID systems any more . Its Off grid use only so if and when buying its good to know . Same with the inverter Edited 2022-02-15 12:50 by bob.steel |
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| ryanm Senior Member Joined: 25/09/2015 Location: AustraliaPosts: 202 |
Yeah, from the little I know about it in Australia the CEC or who ever makes the solar regs is pretty much government sponsored organised crime. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
I gotta get a ute like that I can put panels 3 along in! Mine I can only get a single stack in but I do pile them 35 High! :0) I don't know about the CEC being gubbermint sponsored but they certainly write their own rules and regs they inflict on everyone else. More than clear their last priority is safety and the first is Maximum profitability of the industry. Their approval list is nothing but a protection money racket. Pay up front to have your products put on the list for 2 years then they will become unsafe and you'll have to import something newer and pay again. Couple of years ago they decreed a whole load of panels were now "Unsafe" because they only had 6 earthing holes and they upped the standard to 8. There is only one used at any given time but without those extra 2 Holes punched in the frame, a panel would be a threat to life and limb according to their propaganda. Of course at the same time these mafioso declare to be saving the planet and reducing emissions and other crap..... Funny, would not have though forcing the waste of otherwise perfectly good products and calling something that was fine to put up last week unsafe this week would have been the way to go about that but hey, what would I know? I'm not in the industry or part of the racket and corruption. As for the panels, hardly anything new. There are well over 100, probably 150 sitting down at my suppliers right now. Older low wattage things. I picked up half a dozen for playing and experimenting with I don't want them and I doubt anyone else does when you can get much higher power ones just as easy. I picked up some brand new 325"s last week they were throwing out. Probably leftovers or have fallen off the list so can't be used. Got a load of brand new 250's up the back I haven't even got around to puting up and now I'm having second thoughts as to whether to even bother installing them. Not hard to find 300w+ now and I have quite a few up to 400's so maybe the 250s are not worth it. Things do seem to move fast with this game which is exactly what the CEC would be wanting..... To keep everyone " safe" of course, nothing to do with maximising profits by making people get rid of still perfectly good assets.  |
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| ryanm Senior Member Joined: 25/09/2015 Location: AustraliaPosts: 202 |
I had just assumed that they were set up by the government given their role. Industry group which can essentially create laws? Yeah, nothing to worry about there. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
They are Gubbermint sanctioned if you like but are a private industry lobby made up of and run by the members and businesses in the solar industry that the gubbermint has put in charge of writing all the rules and regulations. What they decide goes. It's all made to look very official above board but completely one sided. The epitome of putting the Fox in charge of the hen house. Much like the AEMO is the same. They are the power industry overseers whom are also private but the gubbermint lets run the show. It's made out they are the industry watchdogs but are in fact 100% the industry itself whom "advises" the gubbermint, Advising being akin to telling them what the rules and regs are going to be including wholesale price of power, Solar rebate rates etc. The other one that does this I know of ( and I am sure there are plenty more) is the Air conditioning Industry. Had dealings with them and talk about a monkey having Illegitimate relations with a football! None the less, they are the governing authority which far as I could tell consisted of a President, his secretary, maybe one other pleb and the rest of the directors are all people with their own ( major) businesses in the industry that get together and write the rules and regs for that game and then the Gubbermint gives the stamp of approval ( like the others far as I can see, with no one else to questioning anything) and the that's how things have to be done and the way they are. In my first hand Multiple experience, One director ( as in multiples) had no clue what the others had decided, Rules that had been passed and what the official policy was from the director/ president whatever. I was responsible for highlighting several " Discrepancies" simply from being duckshoved from one person to another trying to get clarification to some basic questions I had and telling that person what the first had said. At first it was taken that I had misunderstood but then clarified that this was what I had in fact been told and the current policy even though the second person (and others) had not been informed and had great issue with it and thought something else was the case. They couldn't even get their own policys straight with themselves at the same time telling the public and running expensive advertisements " You better do the right thing or you will face heavy Fines". When informing my solicitor and asking what the hell I was supposed to do, he laughed and said you have the discrepancies in writing, do what you want and if they have an issue, we will have them for breakfast. That was some years back and I recently thought about it and looked it up again and they STILL haven't got anything like near a straight policy.... Which I have to admit, after all this time, did surprise me. Complete toothless tigers. Nothing corrupt or suspect about these regulatory bodies making their own rules at all really! |
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| Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 1022 |
That pretty much how it works. The changeover time is about 10ms according to the manual, even that would upset the old computer I had, it was connected to an ups when we had grid power here, sometimes it worked depending on computer load. I have never used or connected the grid to these inverters and so have never had any interruptions (on solar all day and battery all night) plenty of storage. The low voltage solar input (MPPT or PWM) on these models is fed to the battery side DC buss, so will supply power to the converter and charge the battery with any left over, the only way to charge the battery from grid power is to run the inverter backwards and is the reason for the 10ms transfer, thats my understanding of it anyway, pity they Didn't have another small converter that could bypass the inverter and charge the battery independently. The other option that would eliminate the interruptions, would be to have a battery charger that would charge or at least hold the battery voltage from getting too low. I have at times run a generator and a 50Amp 48v charger to the battery, no interruptions to the inverter or output. There is one inverter that has Zero transfer time, I think the way that works is the grid input is rectified and fed to the high voltage DC buss, then the solar power is also fed to the same buss but at a higher voltage (430VDC I think it was) so it will use the solar first until there is not enough, I think the battery-less version works in a similar fashion, or its the same one. Those were out of the price bracket though. Cheers Aaron Off The Grid |
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