Too many threes

[Mr Blobby]

Three phase power with panels on three elevations.  And hybrid inverter with batteries and diverer to DHW and EV.   Talk about a challenge 😬

 

Any advice on her about the best way forward?

 

I think its either solaredge 3 phase hybrid inverter or three hybrid inverters, one on each phase. 

 

The problem is the that the solaredge invertor only works with expensive batteries

https://www.itstechnologies.shop/products/8-000w-storedge-hybrid-inverter-48v-three-phase?variant=40410089881698

 

 

Something like sunsynk can be configured in parallel, as below, but this is a lot more work to set up.  And does this configuration mean the inverters work together to avoid importing from the grid or do they see only their own phase load/ battery charge level/ meter position and fight each other.  I can't seem to get an answer from the suppliers.  

 

 

 

What should I do?  Any advice?  Please?

 

 

 

 

[SteamyTea]

14 minutes ago, Mr Blobby said:

Three phase power with panels on three elevations

Which floor is your greatest daylight power usage going to be?

If one floor is just lights, say for bedrooms/bathrooms, then usage will be so low i.e. 30 or 40 W, it is not worth worrying about.

[joth]

You have expensive requirements therefore the solution is likely to be expensive.

Are you wanting to have the whole-house fail over to battery in case of a grid outage? This adds complexity. (a lot of complexity in the diagram above is trying to provide this, albeit not necessarily in a UK regs compliant way)

Are you resigned to the fact you can't get a net-metered 3ph supply so need to balance consumption and production per phase?

Are you sure you need PV divert or would you be content to run ASHP (or even immersion heater on full) at the likely-cheap times and rely on the battery to smooth over any discontinuity in that assumption?

Can you actually do it all on one-phase and just leave the 3 phase as a future upgrade possibility

 

The more you can cut down your requirements, the more likely you can cut down some of the costs.

 

Have you had a look at Solax 3phase hybrid inverter?

[Thorfun]

is your house actually being run on all 3 phases? we have a 3-phase supply but i decided to reduce complexity to just run the house on a single phase and run 3-phase cable to the garage where the EV chargers will be just in case i decide to go 3-phase charging. Our PV is run off a single 10kW Single phase inverter (the same phase that the house runs on) again to reduce complexity and our battery storage is also on that same phase.

 

IF i ever need 3-phase then by that time hopefully 3-phase smart meters will be more readily available and it can be configured for net metering as @joth mentions above and then it doesn't matter if i draw on the 2 phases that don't have PV on them as any excess generated that is sent to the grid will offset any draw from the grid on the other 2 phases.

[Mr Blobby]

25 minutes ago, Thorfun said:

Our PV is run off a single 10kW Single phase inverter

 

Yes I think running the PV off a single phase inverter will be a lot simpler.  I think the DNO is ok as long as the export is limited to 3.6kw on a single phase.

 

1 hour ago, joth said:

Have you had a look at Solax 3phase hybrid inverter?

 

The problem is the 3 roofs so either a 3 MPPT invertor (which are almost non-existant) or solaredge optimisers.

 

[JohnMo]

I say dump 3 phase, for the solar, do it all single phase, go G99, to see what they allow you to export if that's what you want. Or, slightly less efficient each array its own inverter, then something like a Givenergy All in one, all you pv is connected in to a gateway, the mains goes into the same gateway, as does car charger and battery. Full house power in a blackout (6kW, with 10 seconds at 7.5kW), PV stays online also. The installer can limit output to grid from 0 to 6kW.

[Mr Blobby]

1 hour ago, joth said:

Are you wanting to have the whole-house fail over to battery in case of a grid outage?

 

UPS function for critical circuits would be nice

 

1 hour ago, joth said:

Are you resigned to the fact you can't get a net-metered 3ph supply

 

I just assumed that net metering was standard.  I guess it must must be like that for billing, the net import position.

 

1 hour ago, joth said:

Are you sure you need PV divert

 

I think for hot water and EV charging it would make life easier to get to a zero export position

 

 

1 hour ago, joth said:

Can you actually do it all on one-phase

 

Probably.   I'll be talking to the electrician soon to finalise all this hence looking at the PV options now.

 

[Mr Blobby]

6 minutes ago, JohnMo said:

Givenergy All in one

 

ooh, not seen this before.  Time for some reading.

[Dillsue]

6 hours ago, Mr Blobby said:

 

UPS function for critical circuits would be nice

 

 

I just assumed that net metering was standard.  I guess it must must be like that for billing, the net import position.

 

 

I think for hot water and EV charging it would make life easier to get to a zero export position

 

 

 

Probably.   I'll be talking to the electrician soon to finalise all this hence looking at the PV options now.

 

How much PV have you got on each pitch and what direction is each pitch facing?

[Mr Blobby]

31 minutes ago, Dillsue said:

How much PV have you got on each pitch and what direction is each pitch facing?

 

The plan is for panels on three roofs something like this:

 

SW: 3.5 kW

S: 2.4 kW

NE: 3 kW

 

Solis have a new 3P hybrid inverters with 3 MPPTs.  The problem is its so new that they don't seem to be on sale in the UK yet.

 

 

Edited September 13, 2023 by Mr Blobby

[Dillsue]

7 hours ago, Mr Blobby said:

 

The plan is for panels on three roofs something like this:

 

SW: 3.5 kW

S: 2.4 kW

NE: 3 kW

You'll likely get those on single phase easily as they don't all hit max generation at once and you'll do well to get 3kw out of the NE array.

If you put each array into PVGIS separately, download the hourly figures for each of the 3 arrays then use Excel to combine the 3 data sets, you'll be able to see what your max DC generation is. You'll then be able to size your inverter. One of our 2 systems has 8.5kw of panels spread over 3 compass points and the calculated max output is 5.4kw

You've already mentioned Solaredge and their inverters will handle way more input than the inverters rating, so you can have a seemingly large array hooked up to seemingly small inverter.

What's the peak demand that you need for the house?

[JohnMo]

Another option could be a Tesla Powerwall3, keeping the 3 theme. This should take all you pv directly 

[SteamyTea]

38 minutes ago, JohnMo said:

keeping the 3 theme

We have Arthur C Clarke to thank for that.

 

Rendezvous with Rama

 

[Mr Blobby]

4 hours ago, Dillsue said:

What's the peak demand that you need for the house?

 

Peak demand in the house will be less than 100 amp on a single phase so its looking increasingly likely that everything in the house will run off a single phase.   The three phases will run out to the EV chargers.

 

The problem with three phase inverters, as I see it, is getting things like diverters for Zappi EV chargers and immersion heaters.  Three phase appears to be poorly supported and not well understood by installers and I can do without the hassle and the cost for little benefit.

 

I think the big question is whether the DNO will let me install an inverter bigger than 3.6kW on a single phase with the export limited.

 

Edited September 14, 2023 by Mr Blobby

[JohnMo]

G99 you can have any size system you like, the inverter is just set to match the allowable by DNO.

[Dillsue]

3 hours ago, Mr Blobby said:

I think the big question is whether the DNO will let me install an inverter bigger than 3.6kW on a single phase with the export limited.

 

You need to calculate the DC output from your split array before you speak to your DNO. Telling them you've got 9kw of panels, which you'll never get 9kw of generation from, is much more likely to get a refusal than say a calculated max of 5 or 6kw

 

As johnmo mentions you can have any size inverter you want if you install export limitation. That set up allows you to power the house with as much as you can draw from your PV/batteries but only export what your DNO has agreed.

Edited September 14, 2023 by Dillsue