All is not well in the PW SE multi verse

[Radian]

5 minutes ago, MikeSharp01 said:

I can't put my finger on it but something about +ve feedback is ringing alarm bells in my head but it might just be the beer.

 

Nulling is actually a big dose of -ve feedback ~ the most stable variety.

[MikeSharp01]

31 minutes ago, Radian said:

Nulling is actually a big dose of -ve feedback ~ the most stable variety.

Yes - Get the nulling concept but worry that it only works if the whole thing is synched up in analogue form once you have any DSP (Digital Signal Processing) in in here I feel jittery about predicating behaviour in the nulling and somewhat fear ringing taking hold. I guess that provided, as would be the case, they are both locked to grid phase the various response timings cannot get too far out. 

[SteamyTea]

6 hours ago, pocster said:

PV generation for tomorrow looks low .

Just been out to the car and it is raining here, still warm though.

[Radian]

9 hours ago, SteamyTea said:

raining

What's that? Seem to recall the term from somewhen in the distant past. Spose I could google it.

[SteamyTea]

3 minutes ago, Radian said:

What's that? Seem to recall the term from somewhen in the distant past. Spose I could google it.

August Bank Holiday, 1976.

[Pocster]

So much for “ poor PV generation “ today . Everything’s 100% full and exporting . I’ll wait until later until PV is  low . Then charge EV .

[Pocster]

Actually; I forgot - SWMBO is WfH - so we will start emptying batteries far quicker than I imagine 😁

[Pocster]

Some faffing ! But got it all going for the test .

SE is set to “ discharge to maximise export “ - the alternative didn’t seem to work ! . So SE is giving up max juice to supplement PW to charge my EV as it thinks it’s exporting ….

 

 

[Radian]

So PW sees the 3.6kW solar as the sum of PW solar (0.98kW) and battery discharge (2.67kW) while SE is 'generating'. But I'm confused as to what it does with that info?

[Pocster]

2 minutes ago, Radian said:

So PW sees the 3.6kW solar as the sum of PW solar (0.98kW) and battery discharge (2.67kW) while SE is 'generating'. But I'm confused as to what it does with that info?

What do you mean ?

PW sees this as “real” solar …

[Radian]

35 minutes ago, pocster said:

PW sees this as “real” solar …

Yes, and then what? stores it? Can you show the history of charge level in PW and SE for today?

[Pocster]

4 minutes ago, Radian said:

Yes, and then what? stores it? Can you show the history of charge level in PW and SE for today?

No . It’s being used . PW and SE are both charging EV… 

[MikeSharp01]

42 minutes ago, pocster said:

No . It’s being used . PW and SE are both charging EV… 

How do they, not you, know? 

[Pocster]

3 minutes ago, MikeSharp01 said:

How do they, not you, know? 

Not sure what you mean . House total load is around 7.5kw as we speak . SE is discharging as is PW ( PW can only do 5kwh sustained ) . No evidence of grid draw nor yo yo between them .

This I have seen before and fits in with my understanding of how I expect it to work . How “they” know - not a clue 😁

 

[MikeSharp01]

6 minutes ago, pocster said:

Not sure what you mean

Charging the EV is a correct use case but as I think we have seen before when one of the batteries is flat it will look like an EV and you don't want it, the other battery, to charge it back up so it (they) sort of need to know I think.

[Pocster]

Things of note .

PW max output is 5kwh sustained as is SE 

In reality this isn’t possible. As PW sees SE as solar and inverter max is 3.66 then max output is 8.66kwh . Anything above that will take from the grid . In practice this isn’t an issue ; just make sure total house load doesn’t exceed that ( unless there is PV also ) .

[Pocster]

4 minutes ago, MikeSharp01 said:

Charging the EV is a correct use case but as I think we have seen before when one of the batteries is flat it will look like an EV and you don't want it, the other battery, to charge it back up so it (they) sort of need to know I think.

I changed a parameter to avoid the charge / discharge cycle . SE can only charge from solar or discharge . At 00:30 it will change to charge from grid . At 04:30 it will change back to charge solar or discharge . 

[Pocster]

Stopped charging the EV

PW presumably realises it’s low and at the moment still drawing from SE 

 

 

[Pocster]

Only fly in the ointment might be that PW decides not to charge from grid as it had a ‘good’ PV day … who knows !

[Pocster]

@Radian you know I said I didn’t understand why the PW doesn’t just drain the SE as it see’s it as PV . Well , I think it can . Which might be exactly what I want .

Been fiddling with these settings … ( page 1 )

 

https://www.solaredge.com/sites/default/files/storedge_charge_discharge_profile_programming.pdf

[Radian]

25 minutes ago, pocster said:

@Radian you know I said I didn’t understand why the PW doesn’t just drain the SE as it see’s it as PV . Well , I think it can . Which might be exactly what I want .

Been fiddling with these settings … ( page 1 )

 

https://www.solaredge.com/sites/default/files/storedge_charge_discharge_profile_programming.pdf

Don't forget to make a note of what you change and what it was before!

[Pocster]

2 minutes ago, Radian said:

Don't forget to make a note of what you change and what it was before!

Of course I will …… not !

 

[SteamyTea]

I don't get this.

 

 

Why is the This Year greater than the Lifetime?

[Pocster]

Well ! The test was inconclusive. Looks like PW didn’t take from the grid . Will leave it as is and see what happens tonight.  

[Pocster]

This isn't going to work again tonight!. SE full, PW full and exporting! 😎

 

So PW bound not to touch the grid.

I really do need a cloudy day!

 

I was thinking though. I'm 99% certain I can get the PW to take from the SE constantly i.e. PW stays at 100% as it drains the SE ( ignoring any PV ).

This I *think* might be better especially for winter.

As some of us seem to think; even if both go to charge from the grid what happens when one becomes 100% full. I'm pretty certain as there's been some evidence to support it the PW would start taking from the SE ( after all it would make sense to charge from a source not the grid if it's available ).

This would then potentially mean only the SE is grid charging and PW just stealing.

 

SO! - if PW constantly tops up from SE then during winter off peak SE will always have less charge than PW as PW depletes it.

If they both go to the grid to charge PW won't steal from SE as SE is not 100%. So both in theory will charge from the grid. SE should reach 100% first ( it seems to charge at 3.68kwh and it's capacity is 9.7kw ). So at a certain point SE will be full; PW will see it and start charging from it. But I think in this particular case as both SE & PW will be near to 100% it doesn't matter.

Also as SE needs less than 3 hours to charge I could start its charge 1 hour after PW begins. Thereby the chance of it getting to 100% and PW stealing a significant quantity is reduced.

 

That theory/logic/nonsense make sense?

Edited August 4, 2022 by pocster