February 23, 20179 yr 20 minutes ago, SilverNodashi said: I think in his case, it's a gradual drop as the clouds move in and that's not good either. No, if clouds move in front of the sun and my PV output drops to 500 - 600 watts within seconds from 4000 watt and if my load is 6000 watts, there is nothing gradual. The batteries take a beating. With that sudden high load, the battery volts will take a nose dive. All I am saying is until we have a nice solution on how to control going back to grid, setting 12 (back to grid) is all we have and will have to do for now.
February 23, 20179 yr 15 minutes ago, Don said: No, if clouds move in front of the sun and my PV output drops to 500 - 600 watts within seconds from 4000 watt and if my load is 6000 watts, there is nothing gradual. The batteries take a beating. With that sudden high load, the battery volts will take a nose dive. All I am saying is until we have a nice solution on how to control going back to grid, setting 12 (back to grid) is all we have and will have to do for now. Fair enough. but it doesn't always work like that
February 23, 20179 yr 54 minutes ago, Don said: No, if clouds move in front of the sun and my PV output drops to 500 - 600 watts within seconds from 4000 watt and if my load is 6000 watts, there is nothing gradual. The batteries take a beating. With that sudden high load, the battery volts will take a nose dive. All I am saying is until we have a nice solution on how to control going back to grid, setting 12 (back to grid) is all we have and will have to do for now. there is a way but not for me/us yet:http://www.solarcontrols.cz/en/wattrouter_function.html
February 23, 20179 yr @SilverNodashi jip have a HOW to solve the problem programmatically to switch the entire load at peak. But I have some serious reservations about that. In my humble opinion it is not a very good idea. Ibiza has had some experiences of what I suspect could be problematic. To switch selective loads off is a very good idea. And to make software do it is easy but you need a connection to the devices / plugs and for us that connection would have to be serial, USB or an IP address for I am not going the Pi route no. So to solve the problem programmtically is not the problem. The physical connection to do it is out of my scope. The logic must be carefully assessed and failsafes to be thought of for IF the software has an issue, frreezes, wifi / LAN connection interrupted or whatever can go wrong does go wrong, so you better have the software running on a small UPS at all times like a tablet with a built in battery, is another set of what-if's to deal with for the loads at play here sounds massive to get stuck on either battery or Eskom for hours or days. Switching off selective circuits sound much safer and less problematic like if geyser does not come on, or pump stopped etc, is really not an issue. So bottom line: To tell something to switch off programmitically is easy. Popup window tells you to switch things off. Done. (where is the mic) To make a physical connection between that windows's message and the devices, that the devices "reads" the message, now that is the clever part.
February 23, 20179 yr And o yes, the Axpert has a quirk. Probably for protection. Switching from solar to Eskom is instant. Going back to solar takes a min 5 minutes from when the command was sent before the inverter does the switch back to solar. Keep that in mind.
February 23, 20179 yr 4 minutes ago, The Terrible Triplett said: @SilverNodashi jip have a HOW to solve the problem programmatically to switch the entire load at peak. But I have some serious reservations about that. In my humble opinion it is not a very good idea. Ibiza has had some experiences of what I suspect could be problematic. To switch selective loads off is a very good idea. And to make software do it is easy but you need a connection to the devices / plugs and for us that connection would have to be serial, USB or an IP address for I am not going the Pi route no. So to solve the problem programmtically is not the problem. The physical connection to do it is out of my scope. The logic must be carefully assessed and failsafes to be thought of for IF the software has an issue, frreezes, wifi / LAN connection interrupted or whatever can go wrong does go wrong, so you better have the software running on a small UPS at all times like a tablet with a built in battery, is another set of what-if's to deal with for the loads at play here sounds massive to get stuck on either battery or Eskom for hours or days. Switching off selective circuits sound much safer and less problematic like if geyser does not come on, or pump stopped etc, is really not an issue. So bottom line: To tell something to switch off programmitically is easy. Popup window tells you to switch things off. Done. (where is the mic) To make a physical connection between that windows's message and the devices, that the devices "reads" the message, now that is the clever part. I hear you. Ok, so let's not bother with it then.
February 23, 20179 yr What about reducing load with relay's ? Like switching of the geyser , swimming pump etc when the you pulling X out of the batteries or if the load is above X value rather than switching to grid .
February 23, 20179 yr 1 hour ago, Manie said: What about reducing load with relay's ? Like switching of the geyser , swimming pump etc when the you pulling X out of the batteries or if the load is above X value rather than switching to grid . well, TTT already explained above why it won't work....
February 23, 20179 yr Cool . If you say so. Already tested it and working by me. But anyway you know better than the rest of usSent from my SM-G920F using Tapatalk
February 23, 20179 yr 16 minutes ago, Manie said: Cool . If you say so. Already tested it and working by me. But anyway you know better than the rest of us Sent from my SM-G920F using Tapatalk that's uncalled for....? I don't know better than the rest of anyone. I had an idea but was told it won't work. If you say it, will, then say so and prove me wrong.
February 24, 20179 yr 6 hours ago, Manie said: What about reducing load with relay's ? Like switching of the geyser , swimming pump etc when the you pulling X out of the batteries or if the load is above X value rather than switching to grid . This is one of my ideas: when sudden drop in production occurs to switch off one geyser, if this is not enough switch off second one, if the draw from the batteries is still big changeover one DB to Eskom, and finally, if necessary, changeover another DB to Eskom. Remaining approx. 2000W is usually enough for the reduced consumption. I know you use Raspberries for house automation. Is that what you have in mind?
February 24, 20179 yr 8 hours ago, The Terrible Triplett said: And o yes, the Axpert has a quirk. Probably for protection. Switching from solar to Eskom is instant. Going back to solar takes a min 5 minutes from when the command was sent before the inverter does the switch back to solar. Keep that in mind. 10 minutes with mine, and yes I will keep that in mind, tnx
February 24, 20179 yr that's uncalled for....? I don't know better than the rest of anyone. I had an idea but was told it won't work. If you say it, will, then say so and prove me wrong. No thanks I dont have to prove you wrong. Same like some people said the Raspberry pi will not work. It to small etc.Like you said TTT said it will not work. So then the discussion is closedSent from my SM-G920F using Tapatalk
February 24, 20179 yr 12 hours ago, The Terrible Triplett said: And o yes, the Axpert has a quirk. Probably for protection. Switching from solar to Eskom is instant. Going back to solar takes a min 5 minutes from when the command was sent before the inverter does the switch back to solar. Keep that in mind. MIne is virtually a sec or so later. Occasionally it runs into a longer period of time. My Axpert is set to Appliance rather than UPS and I think it may have something to do with the transfer time. In Appliance mode it is only 20ms whereas in UPS mode it is 10ms.
February 24, 20179 yr 12 hours ago, The Terrible Triplett said: And o yes, the Axpert has a quirk. Probably for protection. Switching from solar to Eskom is instant. Going back to solar takes a min 5 minutes from when the command was sent before the inverter does the switch back to solar. Keep that in mind. Just done the test again on my axpert in UPS mode. Solar to Grid: Immediate Grid to Solar: Immediate (unless you have done a change within 5 minutes then it delays for a period (5 mins - time from last change). Because I try not to switch back and forth I don't see any delays in a normal day with my time scheduling set for a morning and evening switch.
February 24, 20179 yr Just done the test again on my axpert in UPS mode. Solar to Grid: Immediate Grid to Solar: Immediate (unless you have done a change within 5 minutes then it delays for a period (5 mins - time from last change). Because I try not to switch back and forth I don't see any delays in a normal day with my time scheduling set for a morning and evening switch. Yes its immediately, except if you change back an forth a couple of times Sent from my SM-G920F using Tapatalk
February 24, 20179 yr 24 minutes ago, Manie said: Yes its immediately, except if you change back an forth a couple of times It is exactly the same with air conditioners. They build in a time delay for the noobs that want to stop start the compressor 10 times a minute. You don't want to switch between grid and solar continuously throughout the day as your load increases or decreases.
February 24, 20179 yr @Mark At last we now have that sorted too. The logic behind when to switc we will deal with soon once our test site is ready. 2 hours ago, Manie said: Like you said TTT said it will not work Guys, I never said that. Read carefully what I wrote. Here is the summary again. @ibiza 's idea is the best.i.e. switch off one circuit at a time, it is not a train smash then if the software does have an issue and that circuit stays off till human intervention. And I said to do it via software is easy. And I said to communicate to devices / circuits the moment to switch off, that is the challenge for me. But, a friend and fellow developer of SolWEB has an idea for us to add to SolWEB later, using Windows. to switch circuits on and off. And I cautioned why I think it must be very carefully investigated IF you want to switch the entire load more often than what it has to. And it was cleared up that if you switch from Solar to Eskom (instant), you are going to be there for a min of 5+ minutes before you can switch back to solar due to built in Axpert protection. After the built in delay, that switchback from Eskom to solar will be instant. Seriously believe it is a very bad idea switching a massive load all at once backwards and forwards anymore than it already has to be done by the Axpert seeing it can handle the load with battery assistance for a few minutes. The fact that the load is so high for a few minutes, manage that better than adding more complexity. So if you have to do it, do it the Ibiza way, load for load. Less stress, less strain, less drama if things go off kilter for whatever reason. Geysers are perfect to do this with. I recall Eskom, when they "faked" load shedding to entice us towards a nuclear deal, said over and over to switch off all appliances. Why? It was to reduce the startup current when the power was "switched" back on again. Why is switching the load to and from the Axpert any different? 10kw pulled from it, then it is off, then 8kw is put back on ... I say the more you switch the more the components are put under immense strain the shorter their life. Even UPS'es are not designed to handle that kind of strain over and over. And THAT is the major point I made. Be careful why and how you want to do it. Your Axpert may last longer.
February 24, 20179 yr @The Terrible Triplett and others with Axperts, my experience is just the opposite. Grid to solar is instantly but solar to grid can sometimes take a while. I raised the issue of large loads doing the batteries no good as long ago as the days of AICC. @Manie may remember as I believe it was soon after he and Jaco Fourie joined forces for a while. Jaco at the time pointed out the problem of the Axpert taking its time when switching from solar to grid. I spend much of my day in front of the computer, around 8 hours, and since I have MQTT dashboard running on my CCTV monitoring computer with a separate screen, naturally I keep an eye on it. At times when I switch to grid manually, it mostly happens quite fast as also with grid to solar. But there have been occasions when solar to grid took several minutes. The original explanation by Jaco Fourie, who had a Axpert cluster at the time, was that solar to grid could take as long as 15 minutes or even longer. That was when I first proposed a facility to switch to grid when large loads occur on solar as it would protect the batteries and extend the period for which the batteries could supply the normal base load. Read solar as meaning solar/batteries in the above. I keep hoping to find the time to define how a switch to grid on large loads should work but something always keep popping up to undermine it. Of course the solution I am looking for is a feature in ICC. If an acceptable method could be defined and @Manie is willing to incorporate it, that to my mind would be first prize as only existing equipment would be needed. The last thing I would consider is using a bunch of relays and associated equipment to do the switching. That would be akin to a step back to the stone age and unnecessarily complicate matters,. After all less is more, always and in any respect.
February 24, 20179 yr 7 minutes ago, ebrsa said: The last thing I would consider is using a bunch of relays and associated equipment to do the switching. Plus one on that. Unless it is for loads like geysers, pumps kettle etc Microwave no. Hairdryers and curlers are also good to switch off ... wait, let me think ... nope, it is not.
February 24, 20179 yr @The Terrible Triplett what I would propose is a load setting that could be set by the user so every user could decide for themselves. An additional setting of the duration of the large load before switching takes place would enhance matters and take care of much of the frequent switching problem. After all we are in essence talking about setting a few variables to be read followed by a bunch of if then else or case statements primarily as far as the programming is concerned or something similar. Geyser loads do not apply in my case as I use evacuted tubes for the purpose which, to my mind, are more efficient than using solar electricity. So in our house it is mainly the clothes iron, microwave convection oven and sometimes the electric oven of the gas stove. Short duration loads like the electric kettle and several pumps for grey and rain water are hardly likely to cause a significant reduction in battery life or remaining AH before the switch to grid setting comes into effect after a suitable delay. Personally I would set the delay to a long enough setting to prevent the short duration high loads to activate switching. However if you base load is quite high in relation to your battery AH capacity, I would venture that a larger battery capacity to cope with large loads would be a more elegant though of course also a more expensive solution.
February 24, 20179 yr 1 minute ago, plonkster said: Sounds to me like what you guys need is a real hybrid inverter... :-P I plan to get the Infinisolar V series 5kW and then I will be sorted.
February 24, 20179 yr Plus one on that. Unless it is for loads like geysers, pumps kettle etc Microwave no. Hairdryers and curlers are also good to switch off ... wait, let me think ... nope, it is not. Haha you are funnySent from my SM-G920F using Tapatalk
February 24, 20179 yr @ebrsa Jip, that is how I see it too and yes, you are right re. the simplicity of it all. Remember my reservations though. I have similar plans for SolWEB, to do switching based on parameters for my peculiar setup. Now once I have that figured, same paremeters will apply for switching Axpert inverters back to grid. BUT in the Axpert case, the more I think on it, the more I wonder what is going to happen. Lets say you have a load of XXkw and based on parameters the load is switched back to Eskom. No problem being on Eskom for a min of 5min. After 5+ minutes the parameters are met again, so the inverter switches back to solar. Load runs and parameters dictate again a switch back to Eskom, a few minutes later, and all is back to solar based on the parameters. And there the cycles starts - on off on off ... till say min SOC is reached after which the inverter stays on Eskom. Or am I missing the obvious? EDIT: Made a clarification above.
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