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Forum Index : Solar : Grid connected inverter off grid
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Madness Guru  Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Both Oztules and I have the PWM working with no additional capacitors. Unless an issue arises I won't be adding any. 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 |
Thanks mate, it would just run house appliances mainly, most of my tools are cordless, would using one of these help when operating a circ saw? Cheers Caveman Mark Off grid eastern Melb |
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Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 1024 |
I did use the 4048HS (Lightning took it out) and now 5048HS model inverter, just running the house they work ok, 1KW (water pump) Induction motors I have run all day, over 1.8Kw I wouldn't try. Motors with centrifugal start, forget them had enough trouble with them on grid power. That soft start should work, I don't know if it is resistor soft start or SCR type? I have used one of these, https://www.ebay.com.au/itm/Electronic-Regulator-AC220V-10000W-High-Power-SCR-Speed-Controller-Control-Motor-/3023216543 23 works ok so far but its a PITA if you do a lot of start stop operating as you would have to turn the control knob each time you start up.(Do not forget it) The little 4Kw pip did start the 2600w gmc power saw without the soft start but almost hitting the maximum 8Kw surge so I wont be doing that again, best to build a proper low frequency inverter to run power tools. Cheers Aaron Cheers Aaron Off The Grid |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Thanks Revlac, I was planning to buy two of the 4000w 5kva units as they have parallell function. I rarely use big tools. I certainly look into that Ozinverter, just haven't got the spare time now. Cheers Mark Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Hi Mark, If I was in your shoes I would buy one of these LF (not the HF version) Inverters . They will start induction motors and run lots of things that will let the smoke out of the other HF type you are considering. The Ozinverter was based on these, importantly also they are repairable and spare parts are available if needed. The other HF types are very complex and you need to consider them disposable as if they fail that is what you will end up doing with them. Also they don't have a charge controller built in. there is these 80A MPPT charge controllers that are a copy of the Outback. This will cost you a bit more to setup but will be cheaper in the long run. Also you could use that Aurora GTI with this inverter. 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 |
Thanks mate, I did see them but they seem to get savaged a bit like here The HF ones I got a price of 420usd for a 4000w, if they are set as parallel they'll share the current loading so two or three connected together won't get stressed too much. I prob only run a circ saw twice a year. I know it's like how long is a bit of string, but you should see 5 years from that HF one???? Looking at the options, I want it to be ELV 24/48v pref, and plug and play, so setting up that Aurora looks like a too hard basket for now. Also the parallel arrangement of the HF is appealing as it can be added to and has redundancy in the system if one fails. If the power jack ones are actually much lower output than advertised I could just get a bigger one, still don't have the parallel function though. Cheers Mark Thanks for the help guys Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
That video is about the HF version of the powerjack as per above my advise is don't touch them. Stick with 48V, if you go 24V all your DC currents double, eventually you will end up with 48V anyway unless you have a small system. 5 Years maybe but it only takes 10 milliseconds of the wrong load and it's all over. There would be a very good chance that if one goes bad it would take out the other as it would be trying to drive the shorted out dead one as well giving you twice as much smoke. 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 |
Thanks, I'll look into it more tonight, now off to fix some hot rooftops.  Cheers Caveman Mark Off grid eastern Melb |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
OK, regarding the system voltage, if using mppt then you can run upto 120v to keep it ELV and not need a sparky. That can have either 12,24,48v output. If the solar controller is close to the inverter is there really much advantage between 24 and 48v? If all you are talking about is one metre of cables that's not a big concern to me. Is there something I'm missing? I have three 40A mppt controllers in 24v, so if they can still be used that would help, but if 48v is just way way better then they will just have to be replaced. Regarding powering the house, would it be better to have 2x 8,000w inverters rather than one 15,000? I have two power circuits one powers the kitchen and power points in the lounge, the other powers the bedroom and bathroom power points, a breaker for the oven, one for ac, one for fridge, and one for lights. Keep in mind I don't run big tools often, only a couple of times a year, the only thing I think would have a big surge would be the AC, it's 2400w but that will be replaced soon with a more modern inverter that should halve the power req'd to run it. What I was thinking was to split the loads across two inverters. At least that way if one fails I still have some input to the house, and could swap them around if needed. Cheers Caveman Mark Off grid eastern Melb |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Has anyone tested their LF units to see their actual output? That video I posted seems to show the company are pretty over-optimistic with what the units can produce. Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
48 Volt is better for many reasons just not the wires between the inverter and the batteries. If you plan to run a full house with AC, oven etc sell the 24V stuff and go with 48V. I built my own Inverter which will run at 8KW for at least 30 minutes and I run similar appliances etc to yourself. Although during the day the inverter does not work hard as my GTI takes over. I tried the Aurora I bought the other and it works well with my off grid Inverter. You would need a regulator on it to prevent over charging your batteries but it works well and you already have the GTI. Running 2 inverters would work but I found trying to do that meant you could have one smaller inverter working really hard and the one next to it doing very little. With one bigger inverter it would be running at half it’s capability with the same loads combined. But having a plan B is also a good idea, you will need to make that call. You will get better efficiency if you keep the PV voltage lower but for a 48V system you would keep it to minimum of 70V with MPPT. However if you have long wire runs higher volts may be better. I would not contemplate running the AC you have now on one of those HF Inverters, startup power would be over 10KW. This is not an issue with an Inverter AC, they start off slow and build up to full power, there is no big surge at startup. I have a 10KW Inverter AC, it draws 3KW maximum and most of the time it is running it is powered by my GTI. But that can change very quickly with a thick cloud passing over. Keep in mind it is not how often you use heavy loads with tools as it only takes one overload to cause grief. One of the worst tools I have for this is the abrasive metal cutoff saw. It was the only thing that caused my old inverter to shut down, it runs happily with my home made inverter. You can get Soft Starters it needs to be connected in after the power trigger and eliminates the sudden surge. The chinese over rate the power output, so that 15,000 watt one would be able to handle less than half that for any extended period. One of the advantages of building your own inverter is you can avoid cutting corners to save a few cents and end up with a much better result. 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 |
OK 48v it is then, I won't argue. Maybe I'm better off waiting to switch over and just build that OZinverter, or maybe two. I see Clockman makes the boards, is there anywhere local to buy them? What's the estimated cost AUD to make one? I have done a few jaycar kits, certainly nothing this big, I do like the idea of being able to repair it if needed. Funny thing is my AC gets run by that Giandel 2800w pure sine inverter and has done for months, sounds like I have been lucky not to let the magic smoke out. Can you clarify "needs to be connected in after the power trigger" Can I run the AC power into that board and the output to the AC feed line, or does it get fitted in the AC somewhere? Cheers Mark Cheers Caveman Mark Off grid eastern Melb |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Like this???  Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Search Oztules 6KW inverter, you will find lots of information on this site and a few others. Cost to build an Inverter is under $500, have a search around for old Aerosharp 3 KW GTIs, I think there was someone in Melbourne was selling new old stock for around $60 each recently. These old inverters have transformers, copper wire, heatsinks, filters, cases and other bits and pieces that keep the cost down. I did have some PCB's but would need to order more, if you are going this way hang onto the Aurora GTI as it will work in well with what you are trying to achieve. Soft start has to have no power to it until you start the device so must go after whatever is switching on the motor, ie trigger on power tool or contactor in the AC. putting in before this will just have it passing power through with no effect. It must only see power at startup, not before. 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 |
Ripper, I found them, I've bought crap there before. motawizza Will I need one aerosharp to make a oz inverter or buy 2? Cheers Caveman Mark Off grid eastern Melb |
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Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429 |
Buy 2 at least. We stack the cores. For a 6kW inverter the Bare Cores should be somewhere around the 200mm outside diameter, 100mm diameter hole and when glued and stacked need to be about 120mm high. The OzInverter book has the calculations for the cross sectional area of the cores to give you the winding counts, and all info How to build and test for a good toroid. As madness says, around $500 to £600 for a good simple and Robust 6kW OzInverter. When we say 6kW, we mean it run all day at 6kW, go to 15kW for short periods and take fantastic surges up to 30kW to 50kW. But please remember your batteries. The OzInverter Book, project started in early 2015, and the integrated 3 PCBs come with a supplement, with component and parts lists and all other info. Follow the books instructions with the toroid build and the PCB builds, then you will have a cracker of a real 6kW Inverter. Don't worry its not like modern electronics. As the OzInverter is a simple design with through hole components, wide tracks/large pads etc, and generally designed for ease of building anywhere in the World with minimal complications. Our RE motto, keep it SIMPLE, keep it ROBUST, and importantly keep it COST EFFECTIVE. Link to Book and PCB's. ....... Its the cross World postage that blasted costs! http://www.echorenovate.com/new-book--make-a-6kw-inverter.php Everything is possible, just give me time. 3 HughP's 3.7m Wind T's (14 years). 5kW PV on 3 Trackers, (10 yrs). 21kW PV AC coupled SH GTI's. OzInverter created Grid. 1300ah 48v. |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
You need 2 of those Aerosharps to make one 6KW off grid inverter. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429 |
To tempt you, .... Here's the latest OzControl PCB board, components list etc. 2017-12-13_183324_PCBOzContrlBrd12bbList.pdf Everything is possible, just give me time. 3 HughP's 3.7m Wind T's (14 years). 5kW PV on 3 Trackers, (10 yrs). 21kW PV AC coupled SH GTI's. OzInverter created Grid. 1300ah 48v. |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Thanks for all the help fellas, this has been awesome. Now I'll get some good stuff that will suit better. Cheers Mark I ordered two of those units, I'll do an order for the boards when a few bloody customers pay me. It's very hard getting money from people this time of year. They don't mind going on holidays though, without paying my bill  Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
If you plan to build 2 inverters I would grab 4 of those Aerosharps, they are starting to get harder to find. The $75 each is good value, people who don't have access to them have to pay a lot more than that to buy the parts in them that you need. You will be able to start winding the Toroid when you get them the instructions can be found here. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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