Pocster

@Radian a question for you . Why doesn’t the PW just take from the SE when it’s <100% ? What I mean is the PW sees the SE as solar ( regardless of whether it’s PV or SE ) . So say PV production is low today ( real sunshine PV ) and PW is <100% . Why doesn’t PW just drain SE until it’s full ? I.e it’s just PV to it after all …. The answer doesn’t matter ! 😁 - I’m just curious !!

Exactly ! This I have achieved ! The issue is when they both are set to charge from the grid . I’m hoping the PW won’t ‘see’ the SE as SE will be set to charge . Therefore PW will charge from grid . No idea if that will happen ! Frustratingly there’s so much solar I can’t empty the buggers to force a charge at off peak ( caveat being PW will ‘decide’ whether it charges or not ) . Both charging at the same time is my test for winter mode I.e no PV . Best find out now not later ….

Do it and be damned Research as you go , learn as you go . Takes for ever . But what’s the point of life without any challenges ?? 🙄😁

😁 they said the same about underground housing …..

I’ve said it before I’ll say it again ….. If it was easy everyone would do it !

Lol ! Bit of a head f isn’t it ! imagine the fun I have when SE says there’s 6kw of solar at 5am ! PW says house load at 4kwh when it isn’t . PW says PV at 3kwh when there’s no solar because it’s draining the SE . The list goes on 😁

Yes . Whole house off pv and off grid. PW was there long before current installer ( sorry probably should of made that clear ) so SE is an add on . I’ll get it to work ! -

4 hours off peak is 00:30 to 04:30 so no pv Your consumption a bit less than mine 😁

Yes it matters . I only have 4 hours . That’s the total time a depleted PW needs to charge . If one takes from the other - you are simply shifting the load not charging simultaneously ( so do not fill both batteries and equally charge/ discharge cycle reduces battery life span ) . Import bill this month is zero 😁

Yes 2 systems, 2 batteries. The installer ( I asked many questions ) said they could work together and can charge from grid simultaneously . I have that in writing. I went on a holiday recently and explicitly asked the rep in resort if it was "adults only" . They said yes. It wasn't so after the holiday got half my money back. My point being I have nothing to fear if these 2 systems don't work (though I'm sure they will in the way I want ). I see PW as the dominant device here. You have very little control over it. I give it the off peak charge window and it decides whether to charge and how much. It takes into account apparently your consumption, how much PV you generated (just the day before?, or week?, or month? no idea ) also *allegedly* it takes into estimated account PV production tomorrow. SE is dumb. This makes life simpler. It will charge/discharge at set times/days/months - which I can define. The MAIN objective is in winter. 13kw storage in PW is not enough to last the day (even with some negiigle PV). So I need more storage so I can fill my boots with just off grid electricity. Don't want to spend 10k on 3 phase and then ££££ on another PW - oh and maybe rewire my house !!! So a 'simple' battery that sits (how I view it) between PV and the inverter is what I need. When PW is <1% it drains from the SE . This is what I want. If load > 5kwh (max output for PW sustained) it will pull from SE and any PV.. This is what I want. What I don't want is SE stealing from PW then PW stealing from SE. This I think I have stopped. So now; it's just a case can both systems charge from the grid simultaneously .Not one charges, other steals from it. Otherwise essentially only 1 will be charging in my 4 hour window. TBH @ProDave I treat this 'problem' just like building an underground house from zero knowledge. Just give it a go and learn. Doesn't mean I won't fail or f up. Those are guaranteed . Installer will sort this if I can't otherwise I start claims court. They are still in comms with me even though been paid. I also recall they did say that another customer was having an SE added to their PW - so they in theory will experience the same issues.

Sorry I said 3.68kw from memory ( also because inverter is 3.68 max ). But yes it's 3.3kw.

I actually can’t find the rate at which it charges from AC … PW max charge rate is 3.68kwh . SE …???? . That’s what I’m trying to fathom . Though appreciate all batteries are DC . Of course though I may be asking the wrong question ! I’m trying too see that in my 4 hour off peak window ( and assuming they can’t charge simultaneously from the grid ) if there’s a preference to let one charge before the other …

@Radian perhaps you’ll know ! How much faster does DC charge over AC ? How do you compute the max kWh a DC battery can draw ( charge ) ?

I did have reservations they wouldn’t play nice . Installer said they would though it’s the 1st install he’s done like this . Indeed I can’t find anyone else via googling who has . I’m confident I can sort this ; if not via SE options then a plan B is the arrangement of CT clamps . Ultimately SE batteries are easier to come by than PW - so it’s only a matter of time before a PW owner considers a non Tesla battery to extended their storage .

No availability. Also require 3 phase ( 10k for me !! )

This is exactly how I expected it to work . SE slave to PW

Did wonder about the location of the CT clamps . Will try my experiment first 😁

Actually re reading docs it can pV charge whilst in discharge .

SE was 97% when I set it to discharge only . It’s now 100% ! 🙄🙄🙄🙄🤔🤔🤔🤔🤔🤔🤔🤔

Actually a question PW can charge at max rate of 3.66kwh. So needs 4 hours to fully charge . I can’t find a max rate of charge for SE . Because it’s DC will the affect its rate of charge ??? . Google suggests DC charging is faster but no explanation of how you can compute the rate of charge and hence time required .

PowerWall has very limited settings because it’s algorithm does what It wants ! SolarEdge is dumb ( good ! ) so I can set times to charge / discharge etc. It’s default state is “ maximise self consumption and charge / discharge as needed “ . Fine in a normal situation. Here though of course it sees the PW and grabs it . PW then sees SE and grabs it . Installer is oblivious to this issue . I’ve proven it happens so I can stop the yo yo loop . What I’m not sure about is when both need the grid to charge . PW does what it wants ( and I know if it sees the SE in normal mode it will drain it ). So I’m hoping if SE is set to “charge from grid/solar “ it can’t discharge hence PW won’t see it and therefore will use the grid ….

POwer Wall Solar Edge 😁

SWMBO is in with youngest grandson so we are eating kw like there’s no tomorrow. I notice in Tesla app our consumption is 3kwh. This is not possible . SE says solar input is 3kwh . Equally not possible ( SE at 97% ) . It’s stealing from PW !! Quickly go in SE online app set it to discharge only - house load drops to 0.4kwh . There proof !!! Might set SE and PW to both from grid tonight at off peak and see what happens …

Right ! I’ve been thinking about this ….. I think the default SE option of “ maximise charge/discharge” is incorrect in this situation. Essentially ( I believe ) it means the SE will charge / discharge when it wants . This I’m 100% certain as I have proof means it will steal from the PW for its own needs . The solution to this is set a discharge only option . But that means it can’t charge from PV . So it might require that it charges from PV for most of the day then I change it to discharge only at a certain time . This should stop all the stealing I think . I need to empty SE and PW to test this . For winter I assume telling SE to charge only from the grid at off peak means ( hopefully ) the PW won’t steal from it … Makes sense in my head . Update when theory proven or disproven !

Apparently installer contacted SE and there are no known issues . So ! I’ll drain the PW into my EV when it’s low . I’ll do this deliberately at the end of the day so SE and PW have no chance of recovering via PV . I’m assuming the same will happen .