ESS: Questions about

Hello again.
So I have a few, and ongoing, questions about the ESS. I’ll start with the simple ones.

  1. Going through the manual and referencing on my VRM Remote Console I want to check…
    In the menus “Settings<ESS<Grid feed-in”…AC-coupled PV - feed in excess is enabled. The manual seems to suggest (to me, at least) that this concerns devices like a Fronius inverter, which I don’t have. Am I mistaken?

  2. Bit of dof question, but why do the numbers on the Dashboard not add up? That is the diffs between AC-out, PV, Battery discharge. Not crucial, just curious.

  3. Is there a way to diminish the Grid-AC influence, ie, have most of the supply for my meagre loads come from my PV and only when it’s insufficient will grid-AC come flowing in?

(on Q:3 I have currently cut ties with the grid so as to utilize my PV and battery, up to that moment the grid had been bullying my installation taking up 58% of the supply, I want it to be less butch)

More questions to come, in time.

Thanks.
c.

  1. AC PV is for grid-tie ac inverters like the Fronius yes. They normally do not have batteries so their users normally have a arrangment to push excess power back into the grid. If you don’t have it, it will do nothing.

  2. This would all be about effiecencies in the conversions. The heat that devices give when working is because not all the energy you supply is going into the thing that the device does. The rest is heat.

  3. If your inverter can supply 800W of power and anything more will come from the grid, then to longer you can keep your usage to just under 800W the more power will be used from your PV and battery. So if you have a lot of loads using more than the 800W that will all come from the grid even if there is PV or battery available.

Thanks @Louisvdw

I find this to be exactly the opposite in my setup. My 1200VA inverter, when grid tied, rarely kicked out more than 200W, generally peaks at about 150-190W for fridge coming on-running once/hr, then runs for about about 15-20mins at 80W or so. Rest of the time it’s a computer, small load. And yet 58% of consumption came from the grid…hence my head scratching!

In fact, based on discussions had on this thread My Inverter's Capabilities...confused? - #12 by cattus I get the impression the ESS works as a support to the grid supplying the loads. Which leads me to think that if I attach my Installation to a large load (managed during the day eg heating geyser between 10am-3pm) I may then get more out of it. I may have misunderstood though.

Your inverter would only produce what it needs to. It wouldn’t feed back into the grid unless you’ve ticked that option. So if the loads in your house is low, it would only meet those loads.

Let’s say there’s a kettle turned on in your house, plus a few odds and ends, and your house’s total consumption is 2200W. Your inverter would supply 1200W (not sure if there’s limits while operating grid tied), meaning that 1000W would come from the grid.
When the kettle turns off, you have 200W for your house’s total consumption. Now the inverter would supply 200W and 0W would come from the grid.

In reality, you would have a grid set-point of say 50W, so your inverter would aim to always get 50W from the grid.

If you have a Multiplus and a grid meter, I think (don’t know the 1.2kW version) that it would feed back to take the grid meter to whatever the setpoint is, 50W say. So the geyser doesn’t need to be on the backup side of the Multi (and really shouldn’t be on a Multi that small, or even much larger).

Seeing that only a few items are on the inverter I would suggest your change your grid set-point to 0W. And if you know you have more loads being supplied before your inverter and that those are ALWAYS above a sertain point you could also use a setpoint of say -100W (that is the same as the grid meter saying it needs 100W for use before the inverter)
But if you only have small amount of load that is the only power your inverter will produce.

If your inverter output use too much grid power and there are no loads above 800W then it must be a setting.