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Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 09:42pm 02 Jul 2016
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This thread is about my Inverter build based on the brilliant work of Oztules.
I started with 2 Aero Sharp 3000 Watt grid tie Inverters as per Oztules design. What I have done is wind the torriod slightly differently than Oz's method shown here http://www.fieldlines.com/index.php/topic,148717.0.html
Firstly I have wound the secondary with 4 sets of 1.6 MM windings giving 8 mm square rather than the 3 in Oz's build. I have reused the 2 MM wire that came of the 2 original Torroids for the primary. There is 21 sets of the 2 mill wire giving 66 mm square. With 1/3 more copper than Oz's build in the Torroid it should be able to operate at up to 8 KW continuously.
Here is some specs
Torroid core
ID 100 mm
OD 205 mm
Depth 140 mm
Windings
Secondary 4 X 98 turns of 1.6 MM wire Total 8 MM Square
Primary 21 X 11 Turns of 2MM wire Total 66 MM square
More details of the my Torroid build can be found here.
By winding the Torriod this way I will be able to fit everything into 1 original Aero Sharp case and reuse the original heat sink. My reconfigured Mosfet board which is 100 X 250 mm and has the Mosfets soldered to the bottom side of the board so they will be clamped to the heat sink by the PCB.
At least this is the plan, I will post updates as I progress.
There are only 10 types of people in the world: those who understand binary, and those who don't.
oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686
Posted: 10:14pm 02 Jul 2016
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Best transformer I have seen bar none.
The new board will work out very well, and it is easy to replace the fets if needs be too... very friendly to work with.
Can't wait to see the rest of it come to fruition...... and I like the acetone/alcohol laser print thing too.... if I had a laser..... I would try it out tomorrow.
...........oztules Village idiot...or... just another hack out of his depth
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 10:27pm 02 Jul 2016
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I know you are on Flinders Island Oz but you can buy second hand laser printers for peanuts these days. I pickup one beside the road at council cleanup 13 years ago, had done hardly any work, on it it's first toner cartridge and only done about 1,000 prints.
I will be testing out the acetone/alcohol tomorrow, will just be a small sample first off.
I may need to remove the Torroid bolt so it can move to the left, there is about 20 mm to play with there. I have just stuck the heat sink on there with a few nuts as spacers to see how it all fit together. The idea is to leave a gap for air circulation out the top of the case. Also you can see I have cut the case under the heat sink to allow the PCB to fit and for air flow.Edited by Madness 2016-07-04There are only 10 types of people in the world: those who understand binary, and those who don't.
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 10:32pm 03 Jul 2016
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Little bit more progress on the heat sink, found a mistake in my PCB, was a major job to sort it out but I think I have it right now.
The PCB has the screw holes positioned so that they come through between the heat sink fins rather than breaking drills and taps if they where half into the side of a fin.
The hole in the middle of screws will house the thermocouple.
Tried the cold toner transfer but only had a tiny bit of acetone, need to get more tomorrow.
Edited by Madness 2016-07-05There are only 10 types of people in the world: those who understand binary, and those who don't.
oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686
Posted: 11:52pm 03 Jul 2016
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Plenty of room for filter networks now... looking very good..... laser works well too.
.........oztulesVillage idiot...or... just another hack out of his depth
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 12:45am 04 Jul 2016
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Hi Oz,
I was looking at that today, I figure I would need 3 as the Aero sharps are 3 KW sp should be safe at 9 kw. However it will be a tight squeeze to get them in, I was thinking they might need to go somewhere outside the box, will see once the E core arrives. The camera on my phone makes it look more roomy than it is.Edited by Madness 2016-07-05There are only 10 types of people in the world: those who understand binary, and those who don't.
oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686
Posted: 01:08am 04 Jul 2016
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How big is your battery bank.... there is a lot of thermal mass to start with, what is your expected high power requirement for how long?
2 units are worth 6kw continuous... long solar days.... 9kw continuous seems over the top in any circumstance I can envisage. You will need active cooling on the fets for 9kw cont for more than a 5 minutes I expect.... thats serious power.
..........oztulesEdited by oztules 2016-07-05Village idiot...or... just another hack out of his depth
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 01:31am 04 Jul 2016
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My battery bank is 1600 AH, I am want live off grid not exist off as read some where
Worst case I could imagine to pass the wife test as you put it so eloquently. Front load washing machine has 2200 W heater, pressure pump 1000 W Oven 2400 W AC 2000 W plus Fridge, freezer, TV, computer network etc another 600 W. Not all these are on at the same time normally, but it could happen. There have been plenty of times my Trace has been up around it's limit of 4500 W for 30 to 60 minutes. I have told my wife to try to use power hungry appliances will the sun is out. We don't have AC as yet but it is definitely on the list. Plan is to building a house soon also, I would like to do that with as much solar power as possible, which will include welding etc.I would rather have it so that she can use power that way than having a blue about it, been through one divorce, don't think I could survive another.
That is not 9 KW but certainly getting beyond 6 on a regular basis could easily happen. Maybe all this sounds a bit over the top, if so read the first line again.
There are only 10 types of people in the world: those who understand binary, and those who don't.
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 01:59am 04 Jul 2016
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Got this with some components in the mail today.
There are only 10 types of people in the world: those who understand binary, and those who don't.
Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429
Posted: 08:19am 04 Jul 2016
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Hi Madness, I have been watching your build, and its looking good.
AC Coupling to your new Inverters created AC Mini Grid.
I use old/cheap GTI's they have internal Voltage references so if your batteries getting full, then the GTI should drop out when your Inverter raises the AC voltage slightly.
Why AC Coupling?
Power from my GTI's to my 230vac Mini Grid is being used by my houses domestic appliances, ie the batteries are not being used, but my OzInverter is keeping my Mini Grid active. However if the sun/wind goes down then the batteries step in.
I find that with Modern Mono 250w size PV panels I get 10% to 20% output on overcast days/ambient light conditions. So a 20kW array, a gloomy day, your getting that important 2kW.
You probably know all this anyway, but it may help others.
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.
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 12:24pm 04 Jul 2016
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Hi Clockman,
Thanks for your input, still trying to get my head around the grid tie inverter connected to the AC side of the DC inverter. What I am getting at is how well does it regulate the battery voltage, particularly when the batteries are just into absorb voltage. Is it a case of a little grid tie and lots of DC PV that makes it work?There are only 10 types of people in the world: those who understand binary, and those who don't.
Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429
Posted: 12:14am 05 Jul 2016
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Okay.
A brief story. Ohhh not so brief but its all here, i think.
The OzInverter works both ways, it has a H bridge, yes it takes a bit of understanding.
The Inverter unit is switched on using your 48vdc batteries to get it going.
The Inverter is now creating a 230vac (or 230vac or what you adjust the OzControl board to) the 50HZ is stable.
You have DC input from PV panels charging through a DC controller your 48vdc battery bank. I have 5kW PV on Trackers this way with a Midnite Classic and a Tristar MPPT DC controllers. I use these to finish the batteries charging regime.
These DC controllers are expensive, but there MPPT means I can give the DC controllers High Voltages, 200vdc Midinite, 130vdc the Tristar. These high voltages help with cable sizes on long runs, and ease of PV panels string connections. Also importantly I can squeeze every last drop of voltage out of the PV panels on those Murky days.
So Far so good.
So you put 3kW load on your OzInverter AC 230vac side, say washing machine and Microwave. Its sunny so your DC controllers are putting that 5kW of PV into your batteries, but 3kW of that 5kW PV is being used up.
Now as I said those good quality DC controllers are expensive.
However the OzInverter can operate both ways, 48vDC to 230vac and 235vac to say 60vdc.
So once the OzInverter is started by the 48vdc, it can now run backwards.
Now AC Coupling........
GTI's, Grid tied Iverters, are on most domestic dwellings in most Westernised countries. These work by taking the high DC voltage from PV, around 400vdc and converting it to AC 230v to feed back into the National Grid.
The same principal applies to the OzInverters created Mini Grid, I call it mini grid as it is independent of the Countries National Grid, and the OzInverter is giving you 230vac for your domestic dwelling or whatever.
So the GTI pushes back 235vac into the OzInverter and this becomes a DC voltage higher that the battery DC voltage, the OzInverter is back charging, because we wind the toroid tight to specs we get a safe backcharging DC voltage.
Now when the batteries need bulk/absorb charging the GTI pushes back into the batteries at DC. Now when the batteries are filling/ getting full the DC Voltage is starting to push back, the GTI tries to go higher with its AC Volatge to say 244vac.
But all GTI's have Country set operating parameters, set by Goverments, so at about 248vac the GTI shuts down automatically until a lower AC Voltage is detected by the GTI.
GTI's have been around a good 10 years, I use the low frequency ones, they have a toroid inside. I use GTI's below 3kW why? because most folk with PV on the roof want more and it gives me a good cheap second hand market, as these folk update there PV output.
Basically the GTI's I get are good quality, cheap and unwanted, I even get new old stock for peanuts.
For the price of a good DC controller I can get 3off high quality GTI's that are just as good at squeezing that last bit of voltage out of the PV.
Also at 3Kw max each GTI is a safety issue that each GTI drops out and at 3kW its not going to give a 1600ah battery bank to much grief if their ever was a fualt.
I have a fail safe on my GTI's that's controlled by the Midinte DC Controller, when it goes to float an auxiliary relay sends a message to each GTI and relays off on the AC side.
But so far I have never seen it work, as the GTI's just drop out on that slight AC voltage rise.
Conclusion......
Your running 6Kw of loads, its sunny, The 2off 3kW GTI's with there PV arrays are feeding into your OzInverter mini Grid, but your using the 6kW around the House, you are not using your batteries.
So its the GTI's that are directly feeding your House, called AC Coupling.
Neat or what?
Obviously things can be made to work when there is power, and then there is load shedding etc, arduinos etc that can simplify stuff to an automatic regime. The World is your oyster really.
Obviously at night time or when there is poor sun, then your batteries and Inverter will have to do all the work.
Long Live the Simple, Robust and cost effective OzInverter.
Edited by Clockmanfr 2016-07-06Everything 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.
yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166
Posted: 12:50pm 05 Jul 2016
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something must be working slightly different with your GTI's or wiring resistance or settings.
The bulk of EU countries have a GTI setting for AC hiV cutout of 264.5volts, Australia's is 270v.
that's slightly puzzling. I would expect the midnite controllers to be cutting the gti's out rather than them maxing their voltage settings. I'm confused, no wait... maybe I'm not...
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 01:53pm 05 Jul 2016
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I am inclined to stick with the Midnite controllers I am using as I know exactly what the will do and they are connected together. So battery temperature is taken into account so they all work as one, when one say's it is time to go to float they all do at the same time.
Also I have bought 2 Midnite Classics recently and by buying online from USA directly they are about half the price of buying locally, that is even after paying freight.
There are only 10 types of people in the world: those who understand binary, and those who don't.
Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429
Posted: 09:59pm 05 Jul 2016
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Hi yahoo2,
The GTI settings are varied, and discussing them is a minefield.
In practise Mine knock off at 248vac to 255vac it depends.
I note that some GTI manufactures allow a bigger range, I have stuck with SMA SB's as I can also alter their internal settings.
I am always trying to keep my Sustainable Energy cost effective, cheap, yet practical, easy to understand and repairable.
Different needs I suppose.
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.
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 02:42am 06 Jul 2016
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I have been trying all to do toner transfer PCB's, works on small boards but so far have not had success with the larger board.
Has anybody tried any of the Chinese manufactures prices seem to be very cheap but do you get cheap results. Is there any manufactures that anyone is prepared to recommend?There are only 10 types of people in the world: those who understand binary, and those who don't.
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 05:30pm 10 Jul 2016
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Finally a win with PCB making. After trying to use a number of different methods of toner transfer I found one that works quite well for me and my printer.
I have a Kyocera Printer/Copier, what I have found works is to print the art work on glossy paper that has a polished clay surface (most magazines are printed on paper like it). Then using heat to transfer it to the blank PCB, first I tried ironing it on but that was inconsistent, either not sticking in areas or too much pressure causing the toner to spread. Then I used a cheap laminator, that failed, I got better results after heating the PCB in the oven to 165 Celsius then putting it through the laminator.
However I was at the local rubbish dump shop yesterday and got a semi commercial roller type laminator, basically a bigger and better version of the cheap one. The laminator had a smashed power socket and I bought it for $5, I ripped a socket out of an old computer PSU and fixed it.
Running it at full temperature and the slowest speed works really well, just put the printed artwork face down on the PCB and run it through 4 - 6 times. Then soak it in water and rub off the paper. Here is picture of it after etching, some pitting but very usable. This is intended to be a protype and I will get boards made professionally.
There are only 10 types of people in the world: those who understand binary, and those who don't.
oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686
Posted: 07:55pm 10 Jul 2016
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Looks the goods. Did the acetone not do the trick?
......oztulesVillage idiot...or... just another hack out of his depth
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 09:38pm 10 Jul 2016
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Hi Oz,
From what I have read the Acetone cold transfer works well with some types of printers. The information online mostly talks about 30% acetone and 70% alcohol, I found that had no effect, but 100% acetone did work to a point. Vary amounts of pressure helped a little but even when I got what looked like a good transfer started flaking off while etching.
The method I am using sticks like s#%& to blanket, I tried giving it a good scrubbing with a tooth brush after etching and it would not move. Cleans off very easily with acetone though when you want it off. It could be used as a silk screen too but I need to check if the toner is conductive.
With the method I am using it is very quick, from print to etching in a couple minutes. I have done the power board by printing top and bottom, stapling them together and putting the blank PCB in the middle and into the laminator. Waiting for my etchant to recover.
It is two-parts of hydrogen peroxide 3% concentration bought from woolies with one-part Hydrochloric acid (30%). At first it is clear, after the first use it turns brown. Leave it exposed to the air and the liquid turns to lime green colour as the copper in it oxidises. Then it has rejuvenated itself and ready for more etching.
There are only 10 types of people in the world: those who understand binary, and those who don't.
Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429
Posted: 12:11am 11 Jul 2016
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Hi Madness,
That's looking good.
Yes the isolation transformer is tight. Hopefully there is enough room for that big 2uf capacitor.?
Because of the transformer being tight I have done a little reworking at that end of the board.
Its awkward because of the varied isolation transformer sizes, so I have stuck with a maximum size of 3w 220vac to 12vac open type.
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.
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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You will need active cooling on the fets for 9kw cont for more than a 5 minutes I expect.... thats serious power.
