Best way to set this up - solar, batteries and grid


Just in the middle of commissioning our new Battery system.

In Australia - 3 phase.

We have a Main board where this IOTAWATT will be positioned - this is where the mains come in from the street.

So we have the following inputs/outputs

3 x Grid for 3 phases
3 x Solar for 2 x 3 phase inverters (happy to group their inputs which is what i do now)
3 x Consumption circuits that go to another sub board where all the house loads are connected to Circuit breakers etc
3 x Single phase inverters with Batteries attached

Now obviously the grid can be positive or negative depending on how much solar and/or battery activity we have

the Consumption can never be negative as this is where all the loads are

The solar could theoretically be negative at night

The batteries can be either charging (they are AC coupled only) or discharging

So my question is what is the best way to orient the clamps on the Battery and grid circuits ?


A line drawing would be worth a thousand words here Craig. Should be easy to whip one out and I could anotate it.

Yep will do that over the weekend - just struggling with the software on the batteries at the moment.

Last weekend i replaced all of my YHDC clamps with the ones i got from you the ACUCT 40-50 units (this is on my 2nd working IOTA - not the other one with SD problems.)

I have an online portal from the battery supplier - which looks nice but is crap - but am using it for monitoring at the moment

I currently have the inverters set for manual percentages for charging the batteries - 3 inverters, 3 batteries,

The IOTA is reporting power flow as in the picture below whereas the inverters are reporting in the 2nd picture - it is fixed amount that the inverters are putting out (it is set as a percentage of their 5KW rating) and seems pretty accurate so wondering why i am seeing such a discrepancy between IOTA and the inverters reporting ?

I have two of them set for 10% of the 5KW of the inverter (so 500w) and one for 15% so 750w so i should see a total around 1.75 - but IOTA is consistently reporting 1920 - 1950

I am using derived 3phase (and these are on different phases) but my phase voltages are wthin 1 volt of each other at the moment (according to the output from my 3 phase solar inverters)


You’re going to have to bring me up to speed a little more on what you are doing.

Is it:

Consumption: always positive, total what the house is using? Including the battery charger?

GridFeed: Is that positive import power/ negative export power?

Battery: Is that positive battery is supplying power, negative battery is charging?

Solar: Is that positive inverter output?

Assuming the above, and that battery is also part of the consumption, you show 7,238 Watts solar generation and 6,316 Watts consumed, leaving a 922 Watt surplus and a 1,020 Watt export - possible - explain below. That leaves the -1,920 Battery that is charging as part of consumption.

Is that right?

The status display is not a snapshot of a single instant in time. The IoTaWatt is sampling channels at a rate of 32/second. The status display has a damping algorithm so the numbers have a little hysteresis. Unless they are all relatively constant, they wont add up.

What should add up is the Wh over an interval as little as 10 minutes. If you plot Solar, Grid and Consumption, the Wh integration should be Solar + grid = consumption.

Now the battery online portal:

The metrics here appear to be different. Is it:

Load: Positive what your house is using? including battery charging? (Same as IoTaWatt consumption)

Meter: negative import power, positive export power? (reverse of IoTaWatt grid)

Battery: Negative charging, positive supplying power? (reverse of IoTaWatt)

PV: positive supplying power. (same as IoTaWatt)

I’m looking at the graph and in particular the PV pulse at about 11:00am. PV is putting out 10kW and 15kW is being exported to the meter and battery is charging away at it’s standard 1.7ish kW. What am I missing here?

Have you compared “Today Generation” to the running total in statistics when you plot Solar with Wh units for “today”.

Is it possible that you need to use 1,900 Watts of AC to get 1,700 Watts of DC into the batteries? 10% seems like a plausible efficiency if they are converting the AC back to DC for the batteries.

Sorry - as you say a picture is worth 1 thousand words - i promise i will get there by next week !

So in context this has all been running fine for about 6 months or so with no issues - but last week we added batteries to the mix so am not trying to work out the best way to make all the data come together

The consumption is the 3 phases that lead from my meter board to my switchboard where all my loads are connected (except the batteries) - that switchboard is where my other flakey IOTA lives.

So Consumption I treat as being a negative against my total energy “budget”

Gridfeed are the mains from the street - this can be either negative or postive - when it is positive i am drawing from the grid and when it is negative i am feeding to the grid

Yes if positive the 3 batteries are outputting power- if negative they are charging

Yes the Solar inverters are for all intents and purposes always postive (they do draw a little power at night to keep them alive for stats etc)

No the batteries are not part of the consumption figure - they are seperate feeds and go direct to the main board and hence bypass the switchboard/subboard


To clarify

  1. I have 2 x 3 phase Solar inverters - they are measure by the Solar clamps
  2. I have 3 x Single phase AC coupled inverters with batteries attached - each of the inverters is represened in the Batteries Output as a total

When i tell the inverters to charge the batteries i do so as a percentag of the total inverter output (that the battery is attached to) therefore it should be (and does appear to be with Mark one Eyeball) a fairly constant number

Yeah ignore all the stuff on the portal - i think their energy meters which represent power to and from the house are stuffed and can not work in the way i have them configured - waiting for the vendor to confirm that - i trust the IOTA numbers much more than theirs.

The main one that interests me is the big number at the top which is the power being put into the batteries - i think you might be right here - this is the DC watts going into the battery pack (i had not thought of that before) - rather than what is being drawn from the grid - hence the discrepancy with your numbers.

Let me monitor and graph for a while with that in mind and come back to you

Thanks for the time on this one

I wil get the line drawing this weekend to lay all of this out a bit more