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renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 08:16pm 15 Oct 2018
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Phuk!!! Sounds like too hard basket, so that's why no one does it in small units Cheers Caveman Mark Off grid eastern Melb
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 09:32pm 15 Oct 2018
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That is all for a heavy duty commercial transformer that may weigh a ton to hundreds of tons, and may need to be picked up by fork lift or a crane, and transported by truck, then sit out fully exposed to the weather for decades.
All we might really need is a fairly common five gallon steel pail. Sit the toroid up off the bottom with some kind of spacer to allow the oil to convect freely, and just feed the wires in through the open top. A lid would be nice, but not essential, at least to begin with.
If the whole thing turns out to be a crappy messy impractical idea, just let all the automatic transmission fluid drain off the toroid and run it dry as it was originally.
Edited by Warpspeed 2018-10-17Cheers, Tony.
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 11:43pm 15 Oct 2018
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Another reason Mark is that it really isn't necessary unless you were planning to be using 10KW plus for extended periods.There are only 10 types of people in the world: those who understand binary, and those who don't.
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 10:59pm 16 Oct 2018
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I just checked, the arduino has a max temp on the torroid at 45c and the heatsink at 35.I'm actually surprised to see them that high, considering it's been pretty cool here in Melb. The hottest it's been since this was set up has been 27C ambient.
I do try and split the loads, very difficult to train the wife though. She'll often want to have the oven on, set the dishwasher going and go wash/dryblow her hair.(after the bloody sun has gone down) Don't know how many friggin times I have had to bloody explain it GRRRRRRRR Edited by renewableMark 2018-10-18Cheers Caveman Mark Off grid eastern Melb
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 08:39am 17 Oct 2018
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Well, there you are Mark another reason to finish that second inverter .
I'm running two here, the smaller (3KW) one powers the lights only usually and the bigger (6KW) powers the GPO's. As they are located next to one another and the battery bank its easy to swap around if one needs to come off line.
But BEWARE! doing this type split. Both inverters have their output frequency *NOT* synchronised and therefore both house wiring circuits must be completely isolated from each other. If they are not a big bang and two kaputt inverters would result.
Eventually one of my inverters will run the shed only which has the wiring also physically separate from the house wiring. If two pairs of wires, each carrying 240V AC run next to each other out of phase the resulting voltage between them could be over 600 volt at brief times and perhaps over stressing the insulation. Do not try that with a house wiring of unknown condition.
Now here is a challenge for our resident EG8010 specialists: could one chip be somehow set up to drive two different inverters? These would then run syncroniced.
I'm presently tinkering with opto isolated drivers which should make it possible to do that one brain driving two inverter thing. Klaus
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 08:59am 17 Oct 2018
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The German in you keeps coming out Klaus. Nah stuff that having different light/power inverters for the house. The wiring would have to be completely redone. Currently have a changeover switch at the fusebox and a big heavy cable into the garage with a monster plug. That's enough complication for me. What I meant about splitting loads was to run say the dishwasher in the morning, and any other high current loads at different times if/where possible.
The spare was intended to be all ready to go with just a few breakers to turn on the second unit. The way my first one was constructed, it could be repaired, but it would still take a few hours to disassemble, repair and re assemble. My primary unit may last 10-20 years, but I want the backup ready to just switch on, I think having the primary fail would be so rare it's not worth having both running with them connected to an auto changeover switch, that's prob going too far, but an option some may like.
Cheers Caveman Mark Off grid eastern Melb
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 09:26am 17 Oct 2018
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Mark, as I said - I like tinkering . Simple is just not good enough for me if I can build it more interestingly.
You mention repairing them. The PCB's most inverter builders use are not repair friendly IMO. No problem if it never goes wrong. Unfortunately a lot of builders (myself included) found this to be a fallacy. They do go wrong initially .... So I build mine differently. I can: Disconnect the inverter from the battery and mains. Open the cabinet all around. Replace all the Mosfets and capacitors, as well as the totem pole transistors without having to switch on the soldering iron. Put it all back together and re connect.
All that inside one hour.
Can you with yours? Klaus
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 09:35am 17 Oct 2018
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Apart from the drain on your battery running all those things at once should be no problem. However if you expecting the Toroid to remain at room temperature you are going to be just as frustrated as you are with your wife. Nothing wrong with 45 degrees with those loads which I guess would be getting towards 6KW.
Good luck reducating your wife, not a task for the faint-hearted.There are only 10 types of people in the world: those who understand binary, and those who don't.
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 11:20am 17 Oct 2018
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Klaus, really mate I'm not interested in really quick rebuild times. Once the bastard is built and up and running I don't anticipate an issue in the near future. I can't help but think the extra resistance all the connections from those screw in connectors with the fet legs would add up to. Compare that to a fet being snugly fitted down close to the board and soldered in. They simply can't be as good of a conductor. With the rarity of issues it really isn't a factor that should be incorporated.
I had a number of issues with my first unit,I bet my lilly white ass the next one will just go together, cro it and it will be commissioned, driven hard and run for 15 years plus. The problems I had were not the design it was me stuffing up.
@ Mad, yeah 45C is pretty good really.
That's interesting, how many others going off grid have had issues educating family on loads/drains. This really is a very important part of the puzzle and could make the whole equation undone by the actions of just one person that just can't fk'n learn.Cheers Caveman Mark Off grid eastern Melb
Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814
Posted: 12:54pm 17 Oct 2018
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I was both off grid, on tank water and on solar hws- biggest issue was when I had visitors- no, you cant have 1/2hr long showers unless everyone wants cold showers, yes if you leave the bedside light and tv on all night, when you wake up in the middle of the night there will be no power until the sun comes up tomorrow, no you cant wash the mud off your car with my very limited tank water, you can take it down to the dam or it can stay dirty Funnest bit was I had friends with teenagers, all city people from birth- I used to get fresh steak from the next door neighbour who had an excavator (sand quarry)- he would butcher a cow (excavators make both good hole diggers for the entrails, and a good hoist for butchering- that and a chainsaw) When they asked where I bought such nice steaks, I laughed when I told them it had been mooing that morning, and I had done most of the cutting myself... For people who only ever bought steak wrapped in plastic it was an eye opener...
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 09:07pm 17 Oct 2018
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My philosophy exactly. I can open up my inverter and fully expose everything in about two seconds. Circuit boards and mosfets can be changed with just a screwdriver in minutes, as everything either just plugs in, or unscrews.Cheers, Tony.
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 10:45pm 17 Oct 2018
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I have seen a few comments on here about people turning their noses to tank water, at least it does not have chlorine, fish urine and sewage from upstream in it.
We have been away for almost 5 weeks and had somebody house sitting, the only issue was that they used the clothes dryer in the washing machine at night, I had told them not to use the seperate dryer at night but did not say anything about the washer/dryer. Everything worked fine and in spite of all the rain in that time never run out of power, only one day the battery reached 99% charge instead of 100, the same night they turned on the dryer. No MOSFETs needed replacing either so it is fortunate as I have not built my inverter with screw in MOSFETs.There are only 10 types of people in the world: those who understand binary, and those who don't.
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 09:10pm 18 Oct 2018
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When you do an RDS on test the result varies dramatically the further you get from the fet body.
So if you are screwing long skinny fet legs into a connector surely the result must have a detrimental effect. Is there something I'm overlooking here?
Once built, how long would you expect an inverter to last? 1 month 1 year 5 years 15+ years?
If I get even 5 years out of it and need to spend 3 hours fixing it then that's not really too bad.Cheers Caveman Mark Off grid eastern Melb
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 09:45pm 18 Oct 2018
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At least you don't have to be worried if you might have a screw loose. There are only 10 types of people in the world: those who understand binary, and those who don't.
tinyt Guru Joined: 12/11/2017 Location: United StatesPosts: 438
Posted: 10:15pm 18 Oct 2018
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Reminds me of MTBF, MTTR, FMECA, etc. - Reasons I lost my sanity.
And they look bad or good only on paper.Edited by tinyt 2018-10-20
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 12:22am 19 Oct 2018
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Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 03:29am 19 Oct 2018
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Can you be sure screws maintain the same contact in an environment that has up to 40 degree temperature fluctuation daily? What is your schedule for retorquing all those screw connectors? Certainly lots of discussion on Electrical Engineering sites about it.There are only 10 types of people in the world: those who understand binary, and those who don't.
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 03:45am 19 Oct 2018
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How often do you re-solder your mosfets ?
Cheers, Tony.
Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498
Posted: 06:37am 19 Oct 2018
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Never had to resolder my MOSFETs.There are only 10 types of people in the world: those who understand binary, and those who don't.
renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678
Posted: 06:52am 19 Oct 2018
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OK looks like a preference thing then..
Mad, how was the holiday? Better catch up, I just did the mylar over the third secondary while you've been frigging about drinking pina coladas.Cheers Caveman Mark Off grid eastern Melb
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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