Tesla Powerwall 2's + Solar iBoost = Problem?

[TT]

His CPD are  remember

[Countrypaul]

Did you get the phases checked out and if so what is the result?

[Aunat]

No not yet. He didn't turn up... typical electricians... 

[cg617]

I'm confused.
I like drawings, as they tend to graphically show what's going on and if there is an 'error' in the system usually shows it up.
A three phase system, I'm assuming this isn't the UK, don't recognise the equipment in the cabinet.

I would imagine that the solar and batteries are on the same phase, and there can't be any cross connect of power between phases as they are 120deg out of phase.  So this would result in anything on the two phases not having the solar/batteries not benefitting from any of the home grown generation or storage.

[Countrypaul]

I'm confused.
I like drawings, as they tend to graphically show what's going on and if there is an 'error' in the system usually shows it up.
A three phase system, I'm assuming this isn't the UK, don't recognise the equipment in the cabinet.

I would imagine that the solar and batteries are on the same phase, and there can't be any cross connect of power between phases as they are 120deg out of phase.  So this would result in anything on the two phases not having the solar/batteries not benefitting from any of the home grown generation or storage.

If you read the thread he says that there is a powerwall on each phase, and a Solaredge 3 phase inverter.

[Fintray]

I'm confused.
I like drawings, as they tend to graphically show what's going on and if there is an 'error' in the system usually shows it up.
A three phase system, I'm assuming this isn't the UK, don't recognise the equipment in the cabinet.

I would imagine that the solar and batteries are on the same phase, and there can't be any cross connect of power between phases as they are 120deg out of phase.  So this would result in anything on the two phases not having the solar/batteries not benefitting from any of the home grown generation or storage.

Label on the incomer says Western Power Distribution, so definitely in UK.
Western Power Distribution is the electricity distribution network operator for the Midlands, South Wales and the South West.

[cg617]

Countrypaul, my bad, forgot the 3-phase inverter bit and assumed the 3x powerwalls were on one phase.

From the photos and some comments I've drawn up this simplified diagram of the system, probably loads missing though.  But what immediately struck me was where the power flows are in relation to the position of the iBoost CT clamp.
As an aside, the picture from the app showing the power flows doesn't indicate which phase it's showing.  I'm hoping it's not showing the net results of all three phases combined, as this would n't help with troubleshooting.

[cg617]

With the diagram

[Countrypaul]

I think you have misinterpreted the solar iBoost - the Boost is connected to phase 2 and to the immersion heater, it also has a wireless CT oround the phase2 cable in the meter cabinet.

[cg617]

Haha.  Right again, I was rushing, never a good thing.  I did have it on phase 2, but on the diagram had it connected between the inverters and the load.  Then realised it's actual location may be pertinent so drew the 'box' for the cabinet and moved the connection of the CT clamp...  to the wrong phase. 
The annoying thing is the software I used for drawing it is on a computer that doesn't allow loading pictures to this site, so I have to email it across computers...   

[Aunat]

Yes I'm UK - Midlands.

I'm currently at this stage (after talking direct to the Solar iBoost manufacturer)...

The CT clamp is currently on the middle cable coming out of the L2 henley block, and when batteries reach 100% STOC then it does import correctly to the iBoost - there is a however - the iBoost is still 'saving' some energy (ranges from 2-4kwh) before the batteries reach 100% STOC, but at least it's not mimicking any loads on phase 1 anymore. I can't remember which way the clamp is, but it's definitely working 'better' than it was.

I think what I'm going to do is get the immersion moved to P3 and the clamp moved to P3. I've got a feeling it may be something to do with the backup gateway on P3 somehow.

[Countrypaul]

Are the 3 powerwalls connected together at all? I am wondering if they behave as a true 3phase system or just 3 completely independant single phase systems. If they are completely independant then once the one on phase 2 is fully charged I would expect that whatever is exporting from the PV inverter is available to the iBoost (and consequently the immersion), if the powerwall is 3 phase could it be attempting to balance things and therefore causing phase2 to show less PV export than we expect?

Similarly does teh 3 phase inverter export the same power on all phases, or does it try and balance the voltage (and current?) between phases so they all appear the same?

Completely out of my sphere of expertise, I can see the questions, but have no idea of the answers.

[Aunat]

Are the 3 powerwalls connected together at all? I am wondering if they behave as a true 3phase system or just 3 completely independant single phase systems. If they are completely independant then once the one on phase 2 is fully charged I would expect that whatever is exporting from the PV inverter is available to the iBoost (and consequently the immersion), if the powerwall is 3 phase could it be attempting to balance things and therefore causing phase2 to show less PV export than we expect?

Similarly does teh 3 phase inverter export the same power on all phases, or does it try and balance the voltage (and current?) between phases so they all appear the same?

Completely out of my sphere of expertise, I can see the questions, but have no idea of the answers.

Hi Countrypaul,

I'll attempt to answer the questions as best as I can. I come from an IT background, not electrical so here goes.

The Powerwalls are set to 5kW each (not 3.68kW as they are out of the box), which means I have 15kW of power (assuming it's dark, no solar). If I set my Tesla to charge at say 18A, the car will pull 13.5kW from the Powerwalls (my incoming voltage is ~250V) so that now leaves 0.5kW per phase of spare power you would assume - however if I turn say the hot tub on, which pulls 3kW, it will pull 0.5kW from each battery and the rest from the grid, resulting in a maximum power draw of 15kW even though the batteries are on different phases and the hot tub is single phase. This has been confirmed by Tesla to be correct as my app only shows one picture of a Powerwall but with a x3 in the middle of it - so all batteries move up and down with the same state of charge regardless of what phase pulls the electricity...

So theoretically if I had an 10.8kW power shower on a single phase, the batteries would provide 3.6kW each as they all discharge and charge at the same rate.... somehow 

[ceisra]

Aunat
Nothing wrong with a background in IT
My last 25years were spent working on large computer networks with multiple firewalls/internet connections.
Started out as time served electrical engineer then industrial electronics then process control.

My initial comment about moving the clamp was based on the amount of flux that was created around the tightly packed cables.

There are many things that surprise me about your installation but lets not go there.

As a microgen system you should have been provided with full documentation including wiring diagrams, do they exist.

When and if your electrician turns up do you have/is there a plan as to what is tested

Could you also point me in the direction of documentation on the powerwalls please.

Roger

[Fintray]

The CT clamp is currently on the middle cable coming out of the L2 henley block, and when batteries reach 100% STOC then it does import correctly to the iBoost - there is a however - the iBoost is still 'saving' some energy (ranges from 2-4kwh) before the batteries reach 100% STOC, but at least it's not mimicking any loads on phase 1 anymore.

I wouldn't worry too much about the iBoost saving some energy before the batteries reach 100%, in my system the PV diverter for the immersion will come on when there is an excess above what the PW2 can take and there is a bit of toing and froing between the PW2 and the PV diverter.