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rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 801
Posted: 04:42am 16 Apr 2024
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I'm slowly exploring the limits. Living dangerously.
Yesterday we had two segments of underfloor heating running (6,000w total) along with the normal house load for 4 and a half hours ... then turned half off and ran the other for an extra hour.
Seemed to handle it okay. The electronics stayed cool ... just a few degrees above ambient, but the larger two toroids started to warm up to around 50C ... so turned on a pedestal fan which brought them back down to lower 40's. I need to fit the barrel fan I have planned.
Today I'm running both heaters again and I happened to spot the total load right up at 9,663 watts at one stage. Gulp!!
The load pulled the output voltage down to 225.9v at the inverter ... and lower again up in the house at the heater connections ... so it's time to fit the "feed forward current correction" that Klaus used.
I have the current transformer on the input bus, so just need to find/work-out the rest of the process.
Along with the nicely coloured power meter, I have a basic wifi one which enables me to keep an eye on loads without having to head out to the inverter. Here's a screenshot of the biggest load so far.
Cheers, Roger
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 801
Posted: 10:14am 25 Apr 2024
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The Warpverter is still going strong and behaving itself ... and has clocked up 1,616kWh so far.
I picked up another batch of panels, rails and a 5kW Growatt GTI from Marketplace last weekend. 15 x 440w Jinko panels for an extra 6.6kW. It cost me $1,000 but I had to remove them from the house which is slated for demolition.
I've leaned them up against the north facing wall of the shed and fed them in two strings into the GTI. They are all clamped together with a rail all the way through and all the bottoms clamped together ... then tied to the shed.
It was time to jump into ac-coupling so I hooked it up and turned it on ... and stood back. It all seemed to go smoothly and very slowly started to ramp up ... and as its output rose, the Warpverters dropped correspondingly. Was exciting to watch.
One thing I haven't mentioned is that at times the normally quiet hum of the Warpverter would turn into a 4 or 5 times louder rattle/growl ... and I spent ages trying to work out if it was heat or load related. It was always quiet again in the morning but many evenings it would sound really terrible compared to normal.
Anyway I eventually discovered it was my wife's electric blanket. No idea why and I must dismantle the controller and check how it's built. That leads me to explain that this new Growatt GTI has the same effect and any time it is connected and generating any output ... even just a couple watts ... it makes exactly the same noise.
And like with the blanket, when you turn it off, the noise slowly fades away to the normal gentle hum over perhaps 10 seconds.
We've got 19.2kW of panels now. I probably should stop.
24 x 250w = 6kW 24 x 275w = 6.6kW 15 x 440w = 6.6kW
Of course now that I want to see what she'll do, the weather has been very uncooperative ... though I did have a period where it was very impressive. I had both lots of underfloor heating turned on (6kW) plus the normal household load 1-2kW.
The GTI was maxed out and providing 5,012w, the Warpverter 2,236w ... but there was still 170 amps going into the battery!!!
There were times though when the sun disappeared that the battery was providing as much as 90 amps for periods of time ... but overall it all kept up.
Today was similar weather but I had the heating on again and an additional 1kW heater and it all ran from 9 this morning until 3.45pm till I switched the underfloor heating off.
The Growatt says it's produced 25kWh today and the Warpverter is up to 30.75 so far. The best part is the wife isn't complaining about the cold ... and I haven't had to do the wood fire thing yet.
Cheers, Roger
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1369
Posted: 09:58pm 25 Apr 2024
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It's all too hard. Mike.
Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 584
Posted: 08:44am 26 Apr 2024
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Great idea with those solar panels, I assume they face North? Easy to clean too .
Your power demands are incredible compared to mine, glad that your wife is happy running on solar.
I had warpverter growling at times when I was AC back charging, never figured out why, thought it may be one of the chokes I had in it. But it had more serious problems, good to know that yours runs as expected .
That's a good size shed, no chance I could have one like that on my 645 sq m suburban block .
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 801
Posted: 12:12pm 26 Apr 2024
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Thanks Mike and Klaus
Yes it faces directly north ... very convenient layout. I was being lazy I suppose but the inverter is only a couple metres inside the shed from the right hand end of the panels, so it certainly saves in cable too.
We've always been very frugal with our power use because of the cost but with the potential for free power I'm getting a bit carried away. And after years of chasing firewood for heating, I'm a bit over it ... so if I can use what's there for heating as well I'll be very happy.
It is a shame the ac coupling makes it noisier but because it's in the shed and a long way from the living area it's no issue ... and the benefits far outweigh the nuisance value. The part of the shed to the right is my workshop where I work, but it's sectioned off and insulated so it doesn't bother me in there either fortunately.
I can hear it with the door open, but it's normally closed anyway.
The sheds are what sold me on the property when we bought it. The wife loved the house and I loved the sheds, so was an easy decision. It cost a bit to enclose the workshop area but is a great work space. And we have an upstairs section above it for storage. I guess it's one advantage of living in a regional area ... a bit more space. Cheers, Roger
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1369
Posted: 06:31am 27 Apr 2024
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Hi Roger, I have 20 x 480W panels and they are amazing - added to the rest of the solar, it can get us through weeks of overcast rainy weather, providing we take steps to conserve power usage after early afternoon - by that I mean the big oven and larger hot plates. A medium size air-fry oven is handy then, or the occasional small gas bottle and portable stove, but everything else is pretty much normal use.
Even the Air-Con can be run all night and day, I realized years ago that the only to have efficient Air-Con is to have small split inverters (with eco mode) in each room that needed to be kept cool/warm, and only use one at a time, as there are only two of us that works, and cool does not mean stupid cold and warm is not stupid hot, seriously, the things I see people do and then complain about the power bill or usage - absolutely clueless about what it really means to run off OR on grid efficiently.
This is also a small suburban block like Klaus, but I have a heavy duty 6 x 9 shed, and a solid 6 x 6 carport, I still have one side of the 6 x 9 shed roof clear, it's facing south but that makes zero difference with over cast rainy condition, and extra panels for bad conditions don't care much about angle, actually they seem to like almost no angle in overcast dim rainy conditions, but that can create other problems it you don't keep an eye on them.
Love the big sheds you have. My new motto - you can't have too much solar or big enough shed. It's all too hard. Mike.
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 801
Posted: 01:14pm 27 Apr 2024
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Thanks Mike. Having these nice 440W panels makes me wish I'd chased bigger ones earlier. I have virtually filled that side of the roof now and would hate to have to undo all the work and fit bigger ones ... so I think they'll stay and I'll find somewhere else if I end up with more.
There's still 40 metres of fence in line with that shed wall ... so I could start filling that too. Haha
I'm still learning the ropes and have probably hung on too long with the heaters ... so by the time I turn them off the battery doesn't have time to recover as much as it needs. I'll get the hang of it eventually and then try and automate it somewhat.
One of our problems is that the house is very open so it is hard to divide off and just heat or cool one area ... plus there's five of us here and that's harder again.
Our air heater is still performing well but it will make a huge difference to have the big new one on the roof. Still have to finish it but am actively working on it again now that the solar is getting there.
I do enjoy the space here but can see the advantages of a small block. Wouldn't need a tractor and slasher and rideon and all the other work involved in maintaining a large block. Maybe eventually we'll downsize ... though shifting that Warpverter would be a major undertaking. Perhaps we'll subdivide and just keep the house and sheds.
I never expected to be able to run electric heating with solar but seeing we have plenty of space ... and panels are cheap enough if you keep an eye out ... it may be perfectly feasible for several months of the year. And the money saved from power bills can pay for new batches of panels.
I do know a guy online who has lots of panels (cheap secondhand) and several inverters and a heap of forklift batteries who runs an all electric house with three ovens and a jacuzzi on his system. Crazy.Cheers, Roger
Alston Regular Member Joined: 04/04/2021 Location: AustraliaPosts: 63
Posted: 03:16am 28 Apr 2024
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Roger that is all looking fantastic, an amazing achievement. Sorry to hear you had a blow up but I hope you have all of that sorted out. How has the forklift battery been going? Wish I could say I have done some serious testing with mine but because the wife and I are thinking of buying a new place I have decided to park the idea of putting up the panels I have on this on house. I have also not yet bite the bullet and order any cells. So I can't provide much data on my Warpinverter at this stage. I have been keeping myself busy with some woodworking projects instead
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 801
Posted: 11:39am 28 Apr 2024
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Hi Alston, looks like you're a man of many talents. That's a seriously nice table, well done. I'd like to explore cabinet making one day myself, though can't imagine producing something that good.
Thanks for your comments on the Warpverter, it's coming along well ... and I'm still learning stuff about it every day. Today I finally realised why some of the reported numbers didn't add up when using AC-coupling.
Even though I knew the house was only drawing say 750 watts ... the GTI was showing perhaps 2,200w and the Warpverter maybe 1,000w
Yet if I added a 750w heater load ... the Warpverter power monitor would DROP from 1,000 to 350w. It should have gone UP by 750w not down by 650.
Anyway, my revelation this morning was that the Warpverter power monitor is also registering (and adding) the power generated by the GTI.
I missed the obvious when taking all my readings by not noticing that the battery current was going INTO the battery and not coming OUT OF the battery.
Now that I understand what's happening there, I am a lot more comfortable with the GTI backfeeding ... though the accumulated kWh won't be a true output of the Warpverter ... but will include the power that has been backfed through it from the GTI.
The forklift battery is going great and with the sunny day today received a decent equalisation charge and held at 61 volts for a couple of hours. I might start actively looking for a second one to add to it. I've got plenty of room and can use all the power we can generate, so why not.
I've set up a charger to 47.5 and fed through a diode, so that if the battery gets a little low overnight, it will feed just enough in to help cover any loads that kick in ... eg instantaneous water heater that draws 4,000w and drops the dc volts enough to make the lights flutter coz it loses regulation.
Since having all four mppt's connected I haven't really had any trouble until the other night after running the underfloor heaters for too long. I left the charger on overnight but it never went over just a few amps a couple of times ... though that charger can ramp up and supply 50 amps if necessary to get over any humps.
Good luck with your house hunting and hopefully you can find one that suits having heaps of panels and utilising your Warpverter. And I'm still keen to see how your IGBTs perform. Cheers, Roger
Haxby Guru Joined: 07/07/2008 Location: AustraliaPosts: 419
Posted: 09:11am 01 May 2024
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I have a theory about the hum and the electric blanket.
My warpverter would make some "interesting" sounds whenever I turned a load on or off. I guess it was changing its regulation profile from one stage to another. That would only create a funny sound for a short second or two. Like a robotic note with harmonics.
But...I noticed that my cheap soldering iron would upset it but only if it was set to low heat. Internally I believe the soldering iron switches a diode in/out of circuit. So low power is just one half of the sinewave getting through to the element.
That's a great way to get half the power with only one component, but it's also a pretty rude way of doing it.
I "think" that the warpverter is attempting to regulate one half of the sinewave at one lookup table value, and the other half at a different lookup table value. So this might be the sound you hear.
It might be nothing to worry about, but a large load on just one half of the sinewave might induce step saturation in the transformers.
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 801
Posted: 10:11am 01 May 2024
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Hi Phil, thanks for your thoughts.
The Warpverter is surprisingly quiet and has a gentle hum that is not intrusive at all ... that is until that electric blanket is turned on ... then the hum/rattle builds up over 10-12 seconds and stays until it is turned off.
And then it slowly fades away, it is not sudden.
But now that I have the Growatt GTI hooked up ... it gives the exact same result whenever the GTI is outputting any power ... even a few watts. But as above, as soon as there's no power (or I turn off the AC to it) ... it fades away to the normal quiet level.
I dismantled the blanket control and it uses a micro and an SCR but I haven't really tried anything other than an isolation transformer, and that changed nothing.
That does sound quite feasible and it reminds me of what I noticed on a little DSO I use to monitor the AC o/p via a 240-24v tx.
A couple days ago I turned it on and even though the 0-line was in the centre of the screen ... the waveform wasn't centred vertically ... the negative going part was a few volts larger than the positive going portion.
I centred it again but it didn't change the result. I just put it down to the cheap little 'toy' I was using even though it hadn't done it before. Perhaps I'd better drag my bench DSO in there and compare it properly.
One other thing I noticed is that I believe it is the 2nd largest toroid that makes all the noise when it happens ... and for some reason I thought it was the outer primary winding making all the noise. Its made up of multiple strands of 1.7mm wire and is wound fairly tight.
Anyway, you may well be onto something there, so I'll give it some thought and try a few experiments. If you have any more suggestions, I'm all ears. Thanks.Cheers, Roger
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1369
Posted: 10:26am 01 May 2024
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DC injection or bias on the the AC line from garbage loads, like heat guns with a diode to run low heat, they play havoc with the big Toroids, that includes some SCR circuits, but not all.
The choice of chokes can have an affect on how bad that noise is, as can putting the bad load a long way from the inverter, and especially when running a good resistive load with it, tends to help swamp the bad load - or just chuck the bad loads . Edited 2024-05-01 20:43 by KeepISIt's all too hard. Mike.
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 801
Posted: 01:29pm 01 May 2024
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Yes I've seen those discussions and have been meaning to try that out. Which I did tonight ... and on low speed my heat gun causes the same effect and even a bit louder and nastier sounding than the electric blanket.
The heat gun was plugged in alongside the inverter but the electric blanket is 120 mtrs away by cable.
I checked waveforms and switched it on and off but didn't really come to a conclusion. If anything the lower portion of the waveform was a bit reduced when the heatgun was on ... but it may just have been the slightly reduced output due to the 750 watt load on low speed ...
... though then again, while the DC-In dropped a few hundred mV ... the AC out seemed to rise a half a volt or so. Bit hard to decypher because the power meter lags a few seconds as well ... and I really didn't like the sound it was making.
I haven't got a choke on the device at all. I wonder if that is the next step ... or just ignore it and see how it goes.Cheers, Roger
Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 584
Posted: 04:37pm 01 May 2024
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You might remember that I had a choke on the large and medium toroids. They helped initially when starting up but after I worked up a different start up technique I think they did not help with the distortion for some loads. So, if I were in your shoes, I'd leave them out.
I do remember my warpverter making horrible noises when back charging, especially with higher currents. I would suggest you hit the off switch if you hear exceptional loud noises coming from it. If I remember right, I was not quick enough on the switch when mine finally died. And don't apply any AC load until its running with a nice sine wave after switch on. Maybe worthwhile to leave an old CRO connected to monitor the AC, I used a home made 100:1 probe and disconnected the earth of the CRO plug.
AC voltage regulation was never exceptional, + - 5V was quite normal. The current feedback modification only worked in one direction, eg. taking current from the battery. It did not work while charging from the GTI, doing that always increased the AC voltage..
The EG8010 based (or Poida's Nano based) inverters I now use here are a bit better with AC regulation but not by much. I just set AC for 235V at no load and don't worry if that goes up or down a bit as whatever it powers runs just fine.
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1369
Posted: 11:16pm 01 May 2024
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Yes Klaus is correct in that I forgot that you are using a different inverter, so the waveform distortion will appear to be different, and choke not relevant to your inverter.
The AC voltage display is likely not a true RMS display and the apparent voltage will change with waveform distortions. Some meters that boast true RMS are not.
I never worry about slight variation in indicated AC output. The loads should not give rats whatever - OK I'm wrong !!! Maybe some snotty lights can give hint of a change, whatever! It's all too hard. Mike.
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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