I get that. I was talking about the white wire from Inverter2. Your Inverter1 is not producing any power in the cited period. Inverter2, which seems to be the primary inverter, is showing half the power needed to match the load because the Black wire is being interpreted at 120V. The White wire is the other half of the story and should show the remaining power needed to reach equilibrium. Humor me. I deliberately included the start and end unix times.
InverterW1 should be zero.
Don’t know the other components in the circuit, but they appear to be netting the two electrically, as I suspected. That reinforces my theory when I say I don’t see the point of limiting the inverters if the meter doesn’t net, more or less the same way.
Occam’s razor.
Whaaaaat? I’m not advocating doing anything to those inverter CTs. IMO they appear to be working exactly as advertised.
The question is whether your meter is recognizing that there is no net power being exported. I believe it probably is, but you need to accumulate some history to prove that out. I am advocating that you not change anything and wait until you have 100 or so kWh under your belt, then compare IoTaWatt kWh to the meter.
I wrote the above before I read your last post…
So far it seems as if the electric company meter is slowly starting to show more power used than the iotawatt says I’ve used…which would indicate that the meter is seeing the backfeed (if it’s happening) as power I’m using…and the iotawatt (since I’m allowing negative values) is not…
I hope these damn inverters aren’t producing like the iotawatt is presently configured to read them…I had a retired electrical engineer convince me that the inverters would work and not backfeed…he owns 2 of the inverters himself…he said they would work because they are feeding the overall mains voltage…I think he is confused about how the ecompanies meter reads our power usage
This will take time. Lets get the baseline with the current setup. If you want to upload to influxDB or Emoncms, you can replicate a meter that charges per leg for export with 5 or 10 second granularity respectively.
I hate to bother u more and ask how so I’ll search how…
Btw I love how fast the iotawatt is at responding to my loads…a lot faster than I thought it would be
You can send the absolute values of the two mains to Emoncms and create a feed that is the sum of the two and the running kWh total. It’s pretty straightforward.
IoTaWatt doesn’t keep derivative data, only the raw data, so even though it has the mains at 5 second resolution, it can only produce the net, not the sum of the derivative absolute values. There is a need for that, and I have some ideas for the future…
You don’t have to do that right now. You can setup an Emoncms account at anytime and have the IoTaWatt upload historical data.
Only other difference today is that I have the pool pump on and it hasn’t been on last few days…the pool pump is on main2…so this means that main2 had more loads than main1 today…usually main1 has more loads when pool pump is off…but shouldn’t one of the inverters wires match the output of the underfed amount just like in the pic where u circled
The mains mirror zero with an amplitude equal to the Watts of imbalance between the two legs. The inverter leg is half of your total load. There is no negative power when the total load exceeds the output of the solar or there is no imbalance.
I spoke to soon, I just realized the inverters weren’t covering all the loads at the time…but still confused as to why there is a backfeed if the inverters didn’t think they were fully supplying the loads…but I guess they still could backfeed and underfeed at that time…ima think on it lol
I’m just about half way to the 100kwh mark to have a good test to see if my ecompany meter is reading my limiting inverters supply (when legs loads are unbalanced) as backfeed and underfeed of the mains…I’m gonna post the results as of now…
Started meter reading at 27252 kwh, now the meter reads 27298 Which equals 46 kwh used…
At meter reading of 27252, the iotawatt displayed 59.6 kwh used…
At meter reading of 27298, the iotawatt displayed 106.4 kwh used…
Which equals 46.8 kwh used…
So ecompany meter is saying I’m using less than iotawatts readings but not by much…
This tells me that the ecompany meter is not seeing the overfeed-backfeed represented in the graphs above as power I am using, otherwise the ecompany meter would start to read as if I was using more power (not less as the results are showing) than the iotawatt displays …so the ecompany meter is acting as a “net” meter same as iotawatt reads the mains of split phase panel to get a “net” total…
I have read from many sources that the typical ecompany meter ppl have will charge for backfeed same as if we were using that power…well that seems as if it’s true and not so true…the way I now understand it considering the above kwh results is that the ecompany meter will only charge for back-feed if the backfeed is coming thru both wires (of a split phase main panel) at the same time…,if only one side (of main panel) is being backfed then the other side will be getting underfed and those two values equal out to zero grid usage in the meter…
I will test at 100kwh used (since test started) to further confirm this…and ofcourse I’ll test like every hr till that 100kwh mark is reached lol cuz I’m really having fun with this iotawatt!
I’ve reached 100kwh since I started the test and the iotawatt is still right on with what electric company meter says I’ve used…this confirms that my 240v single phase inverters feeding a split phase main panel are not overfeeding into the grid on 1 leg…iotawatt has put my mind at ease…many ppl say u cant use 240v single phase inverters on a split phase panel and I just have to say they are wrong…thx bob for everything u put into the iotawatt… great product! I’ve talked it up so much I have 2 other ppl purchasing it
I’m glad it has worked out. I learned some new things here as well like about limiting inverters. You might investigate how you could introduce opportunistic loads to harvest the substantial solar output that is being left on the table.
You may both be right. Your inverters are limiting and so don’t create a net 240V export. What would happen with non-limiting inverters is not explored here.
Yes sir I meant 240v single phase limiting inverters…it’s said (proven wrong) to only use 120v inverters on each phase, and if u don’t it will not limit correctly.
What do u recommend for using the excess solar…I was thinking about diverting to hot water heater but the hot water heater is already consuming power only during peak inverter production cause we turn it on at that time…we also use dryer during high inverter output. Sorry Ik this isn’t the topic here, also my home is newly constructed and well insulated so we shut the air off in the morning (cuz we like it cool at night) and then the air isn’t needed till around 2pm…I’m thinking of maybe doing the opposite and setting the ac colder during the day to use more of available solar then shut off ac when solar lowers output, but I’d think we would still want to turn the ac back on at night to cool it off before bed.
This is were it will help (u said u are working on it) to be able to set an exact time and date for what is displayed on the graph and so the totals can be viewed for that specific time frame…I could use batteries to power inverters to save excess solar…but I really didn’t want to add batteries but yeah a lot of power wasted
Where’s his powerwall
Happy to discuss my Tesla Powerwall and others who build their own units like it. You can do a search on YouTube for such DIY. I wanted to have a fully supported and integration of the Powerwall solution. A great way to store excessive PV generation. The home get satisfied for power needs, then the battery, and once charged, excess goes to the grid.
