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Forum Index : Electronics : 6Kw Ozinverter build
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Madness Guru  Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Deleted 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 |
Dunno why you deleted that Mad, I thought it was quite relevant, anyway, yes I'll try it the easy way first and probably be happy with it. Not much progress on the build, still waiting for most parts to arrive. Didn't have spare time to wind primary recovered wire. 36c tomorrow, not too inspired to stretch and twist crap at the local footy field after a day on rooftops.  Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
I figured you can work what you think is best. 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 |
Always happy to hear options, don't forget others may benefit from ideas posted too, even if I don't use them. Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Mark sent me a PM about testing MOSFETs, I have put the reply here so others can find it too. I use my 48V battery bank but you don't have that ATM. You could use a 12V battery, I made up a tester before using a hard drive connector off an old computer power supply to stick the FETs in. I use 2 of the big 33 ohm resistors off the Aeosharp PCBs in parallel looking at the fet from the front you have gate, drain and source in that order left to right. So you need +12 (never 48V) to the gate to turn it on, the drain is connected to to the resistor and resistor is connected to positive power. Source is connected directly to ground. It is far easier if you have meter leads with small alligator clips and you must connect as close as possible to the body of the MOSFET (ie less than 1MM away), connect one to middle leg (drain) and the other to the source (right side) when power is applied to the MOSFET with all these connections we want to measure the voltage across these pins. You will need to measure the current at least once also then you can use Ohms law to calculate the RDS ON (resistance Drain-Source while turned on) For HY4008's it should be 2.7 milliohms which is a very tiny amount and why the cheap little testers can't measure it properly. Sometimes you will get a higher reading, disconnect and reconnect the MOSFET as it needs really good contact, if you got them from the same supplier I did they have always been on spec or better, but if you get any FETs that are 10% or more higher (lower volts is better) than the others put them aside and don't use them for the Inverter, they would fine in the fan controller. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Mark, you might also read my post on this subject: post Is a bit down, one post above the bottom of the page. If you test quite a few mosfets - and I think you will  its well worth while to make up a little test rig.Especially when you are selecting similar RDSon devices, it is *essential* that your measurements are spot on or you might not bother with this, its a very small voltage you are measuring. Note my comments with regard of using 10A test current, it gets you around messing with Ohms law at each measurement  .You'll need a variable power supply capable of 10A though. Klaus |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Thanks guys, I bought 40 of these thinking that I could just pop them in and all sweet. I'll test them and hopefully there aren't any more than 16 out of spec. Cheers. Cheers Caveman Mark Off grid eastern Melb |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Got my new controller today.here It can take a higher voltage than my previous ones (100v current max) so I wired everythin in 2 series and parralled them, now I can series three to get a tad under 120V open circ so it's still classed as ELV, so less line losses, sweet! But need to get up there and rewire now.  Cheers Caveman Mark Off grid eastern Melb |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
I have bought several hundred HY4008's from the same supplier, I have not had one that was out of spec. That Fangpusun is a rip of an Outback, although you can run higher voltages you will get higher efficiency in the controller if you can keep you panel voltage as low as you can above 65 volts. The difference is not huge but there is a few watts you can pickup,=. Probably what you lose in resistance at a lower voltage negates any gain anyway unless you go to heavier wiring to the panels. What you can't do is exceed 150 volts, the critical time for that is predawn on a very cold clear morning. There is a temperature coefficient for all panels and you need to be sure the open circuit voltage won't go too high when they at their coldest. However, if you are >120V you will be well within the safe zone. How many beers do you plan to have before installing it? 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 Mad, so don't bother testing the fets, just fit them? Cheers Caveman Mark Off grid eastern Melb |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
That controller was meant for the 48v bank, (yet to come) so I wasn't planning on fitting that controller yet, but probably should test it for warranty purposes. Still only have 3500w on the roof, I was waiting to get all the bits ready and then put in the changeover switch, not too trusting of that giandel inverter running the house, I'de rather wait till the OZinverter is ready to feed the house. When it gets put online I'll fit the rest of the panels. Cheers Caveman Mark Off grid eastern Melb |
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| Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Ha, you like things going puff, no? If you used only 4 of them then, no testing for RDSon but I'd still test them to see if each actually switches on. Fitting a dud to start with might be regretted later. If you use several in parallel, as most builders do, then matching RDSon is a very good idea. Perhaps you learn best by experience? If so disregard all our helpful hints and just put the thing together anyway. There's a slim chance it works. In mine and mad's case it was magic smoke, lots of times  Klaus |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
You can test the charge controller on a 12V battery, just follow the setup procedure, first setting is voltage. As for FETs I was not suggesting don't test them just that I have had a good run of no bad ones. 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 |
I do appreciate all the helpful hints and I'm sure I couldn't build it without the help of everyone on here, I was just going by what Mad said in regard to "buying several hundred from the same supplier and not having a dud one". Cheers Caveman Mark Off grid eastern Melb |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Hey guys I have been testing the components and most are fairly accurate, however the 100uf electrolitic caps are testing around 86. The 100nf monolithic are coming out at 34nf!!!  Am I expecting too much or is this way too far out? Surely the circuit won't operate as designed if the values are only 30% of what they should be. I tested them with the multimeter too and the tester appears to be accurate. Cheers Caveman Mark Off grid eastern Melb |
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| noneyabussiness Guru Joined: 31/07/2017 Location: AustraliaPosts: 513 |
I have one of those... they usually pretty accurate ( to a point )... make sure it is calibrated... But i personally have had stuff that far out, usually old caps etc. That would be expected I think it works !! |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
The multimeter showed a very similar result. So that 100nf mono testing at 34 surely needs to be tossed?? How far out do you normally accept as within spec? Cheers Caveman Mark Off grid eastern Melb |
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| noneyabussiness Guru Joined: 31/07/2017 Location: AustraliaPosts: 513 |
i would personally... because i have heaps spare.. but if in a non critical roll and the only one you have then keep it... the letter next to the number usually is the tolerance spec , 104J for example the " J " represents say 10 %... sometimes though it can mean the voltage rating.. just to mess with you  I think it works !! |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Thanks mate, I ordered some more. With the Metallized Polyester Film CBB Capacitor I was under the impression they are not polarised here backs that up. But here at 15.25 min mark the fellow show they are different. So since no one seems to worry is the difference so small that you wouldn't worry about it? Cheers Caveman Mark Off grid eastern Melb |
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| renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Well the new 100nf caps came from an Aus seller, only one was close (98) Rest were in 70's NOT HAPPY JAN !!!!!I was remembering something Mad told me te soldering the small chip and it took 30 min to find it, thought I would cut and paste here for any following to see it in a relevant area. Quote Mad "The trick to solder them is to use SMD flux, you need to do it under a magnifying glass. Put flux on the PCB pads and get the chip in place and push it down into the flux. Then with a fine pointed iron and virtually no solder on it touch one of the pads, solder should flow from the tip across to the chip connection. Make sure it is exactly in the right place, if not correct it, once it is right repeat the same on the opposite side so that it can't move. Once you have the first 2 on do the rest but always keep as little solder on the iron as possible otherwise it will short out terminals. Have some solder wick on hand to clean up excess solder if needed. When done check every connection for continuity and shorts. Don't put solder on the job just the tiniest amount on the iron, the flux will do the rest for you." End Mad quote. Other thing that pissed me off was a bus smashed into me, now have a smashed up tray, gearbox and transfer case leaks, a day off work for the hospital to check me over (needlessly) now have to deal with insurance Co and hopefully it gets fixed properly. Cheers Caveman Mark Off grid eastern Melb |
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