Inverter confusion

[Pocster]

5 minutes ago, S2D2 said:

Yes I've seen 6.2kW today on a 5.5kW "max" - never for long, I assume it's a nominal max which it can go over for short bursts.

Think now I want more PV - but have run out of roof space . Perhaps foldable PV that opens up on my front garden and folds away when it’s in the way . More PV , more storage , more export ( though I haven’t and can’t reach that yet ) .

Sounds like a project for @Onoff

[SteamyTea]

6 minutes ago, S2D2 said:

Yes I've seen 6.2kW today on a 5.5kW "max" - never for long, I assume it's a nominal max which it can go over for short bursts.

About 13% then.

Some of it is to do with the module's long term performance warrantee.

If you want to guarantee say 80% after 10 years on a 300W module, then fit a 330W module.

[S2D2]

Just now, SteamyTea said:

About 13% then.

Some of it is to do with the module's long term performance warrantee.

If you want to guarantee say 80% after 10 years on a 300W module, then fit a 330W module.

To clarify, I'm referring to the inverter's stated DC max of 5.5kW, the panels are 5.2kWp which as you say is regularly exceeded due to the artificial conditions in which it's calculated.

[Onoff]

3 hours ago, pocster said:

Sounds like a project for @Onoff

 

Too busy mate. Just FINISHED a box section arch for the pub and a reversible sign. Paid in pints and crisps! 👍

 

 

 

[Pocster]

36 minutes ago, Onoff said:

 

Too busy mate. Just FINISHED a box section arch for the pub and a reversible sign. Paid in pints and crisps! 👍

 

 

 

Ffs !

You’ve got ufh , boiler boxing , gobble doorbell to finish ! - I give you another proper job and you turn me away !

[Onoff]

51 minutes ago, pocster said:

Ffs !

You’ve got ufh , boiler boxing , gobble doorbell to finish ! - I give you another proper job and you turn me away !

 

The list is getting longer but as SWMBO seems to have no interest in projects here I have to find outlets for my talents elsewhere! 😉 That it serves beer and the conversation is better is just the icing on the 🍰.

Edited May 7, 2023 by Onoff

[Onoff]

17 hours ago, pocster said:

Think now I want more PV - but have run out of roof space . Perhaps foldable PV that opens up on my front garden and folds away when it’s in the way . More PV , more storage , more export ( though I haven’t and can’t reach that yet ) .

Sounds like a project for @Onoff

 

Thinking about this you could cover the garden with PV panels and have an AstroTurf "cover" on a  garage door type roller. 

 

To use as a lawn you would of course need to have a protective shield if you will over the PV panels, have you any experience with walk on glass?

[Pocster]

18 minutes ago, Onoff said:

s, have you any experience with walk on glass?

No 

[Marvin]

Hi @pocster

 

I've read all the posts about this inverter confusion and have come to the conclusion that it's not the inverter that's confused.

 

To follow the train of thought (only about the original issue that is) I think requires a clear diagram with details on it.

 

Also several questions cannot be answered because they are not specific enough, other items raised by others with there limited info just confuse the issue:

 

17 hours ago, S2D2 said:

To clarify, I'm referring to the inverter's stated DC max of 5.5kW, the panels are 5.2kWp which as you say is regularly exceeded due to the artificial conditions in which it's calculated.

I've never heard of this! There are so many variables as to why they would never reach there full potential that I can only think that something has been miss manufacturered.

 

[SteamyTea]

31 minutes ago, Onoff said:

have you any experience with walk on glass

You are cruel.  Just think how much electricity could have been bought it, years worth.

[SteamyTea]

1 minute ago, Marvin said:

Hi @pocster

 

I've read all the posts about this inverter confusion and have come to the conclusion that it's not the inverter that's confused.

 

To follow the train of thought (only about the original issue that is) I think requires a clear diagram with details on it.

 

Also several questions cannot be answered because they are not specific enough, other items raised by others with there limited info just confuse the issue:

 

I've never heard of this! There are so many variables as to why they would never reach there full potential that I can only think that something has been miss manufacturered.

 

I explained that.

[Marvin]

15 minutes ago, SteamyTea said:

I explained that.

 

Hi @SteamyTea

 

Considering that depending on what part of the world @S2D2 has the PV array will make a difference, I will us as an example Banbury UK to explain why I find it hard to believe that the panels are the reason:

 

The peak of the height of the sun 2 days ago in Banbury would mean the sun was at an altitude of about 54.45 degrees

 

If the:

panels were at an angle of 35.55 degrees. 

panels face directly south. 

panels have no shading or dirt of bird poo on them.

inverter has no power loss converting DC to AC

DC cables cause no loss

 

and you still achieve 13% over the stated power of the panels, then yes, but would it flick on and off of the excess level? Would it not rise slowly with the sun angle? 

 

Surely its more likely that the ping is caused by the inverters response?

 

Respectfully

 

M

 

 

 

 

[SteamyTea]

18 minutes ago, Marvin said:

will us as an example Banbury UK to explain why I find it hard to believe that the panels are the reason:

 

The peak of the height of the sun 2 days ago in Banbury

We may be talking about different things.

But here is a chart of horizontal plain solar power from Banbury on Saturday.

Not a very impressive day, quite peaky.

 

[Marvin]

Yes I was using Banbury as an example. I do not know what part of the world @S2D2 lives in.

 

I was using an example where IF Banbury was the location and had a completely sunny day what the suggested outcome would be IF the panels were over producing. 

 

M

[SteamyTea]

6 minutes ago, Marvin said:

I was using Banbury as an example

I generally use Leicester as my generic England PV spot. It is about halfway up, and halfway across the country, and reasonably flat.

I have been to Banbury, made me cross.

[Pocster]

On 06/05/2023 at 12:20, pocster said:

My export on PW is indeed wrong - set at 3.68.

I assume it's a simple case of contacting Tesla and they'll change it?

Presume they can validate themselves it's within the limitations of what the DNO has set.

I emailed Tesla explaining that my PW limit is incorrect and that my total inc PV is 8.6 ; so PW needs to be 5Kw.

 

Got a reply today that it's all be changed.

 

Indeed it has. They've set my PW to be able to export at 8.6!!!

 

Wonder what DNO will think if they knew ! 😮😎

[S2D2]

2 hours ago, Marvin said:

 

Hi @SteamyTea

 

Considering that depending on what part of the world @S2D2 has the PV array will make a difference, I will us as an example Banbury UK to explain why I find it hard to believe that the panels are the reason:

 

The peak of the height of the sun 2 days ago in Banbury would mean the sun was at an altitude of about 54.45 degrees

 

If the:

panels were at an angle of 35.55 degrees. 

panels face directly south. 

panels have no shading or dirt of bird poo on them.

inverter has no power loss converting DC to AC

DC cables cause no loss

 

and you still achieve 13% over the stated power of the panels, then yes, but would it flick on and off of the excess level? Would it not rise slowly with the sun angle? 

 

Surely its more likely that the ping is caused by the inverters response?

 

Respectfully

 

M

 

 

 

 

Yes, we're talking about the inverter limitation, not the panels. I don't know anything about the DC max other than it's listed on the data sheet for the inverter.

 

Wrt the panels question, the biggest power output I see (119% of kWp rating) is not on a cloudless day but rather when there is a break in the cloud so the panels are cool then suddenly receive both direct sunlight and indirect sunlight from clouds. This transient nature makes it very difficult to determine whether the inverter reacts and pulls it back to DC max or whether it's just a change in indirect sunlight levels that reduces the output. Someone who knows more about inverters may be able to enlighten us.

[Dillsue]

3 hours ago, pocster said:

They've set my PW to be able to export at 8.6!!!

PW spec says 5kw sustained 7kw short bursts so may be worth checking they dont mean collective export is 8.6kw when SE is at max??

 

There wasnt a note at the bottom saying you got what you want but warranty is now void

[Pocster]

15 minutes ago, Dillsue said:

PW spec says 5kw sustained 7kw short bursts so may be worth checking they dont mean collective export is 8.6kw when SE is at max??

 

There wasnt a note at the bottom saying you got what you want but warranty is now void

I'll leave it for now. AFAIK PW can now export at 8.6

 

Of course this wasn't what I asked ; I asked for 5. So if it blows up it's Tesla fault 

[Pocster]

17 minutes ago, Dillsue said:

PW spec says 5kw sustained 7kw short bursts so may be worth checking they dont mean collective export is 8.6kw when SE is at max??

 

There wasnt a note at the bottom saying you got what you want but warranty is now void

What confuses me is that in effect I have 2 inverters. So the SE/PV when exporting will go through the SE inverter which is capped at 3.68.

When PW exports it naturally goes through it's own inverter ; so in effect neither know nor care about the other....?!?

Edited May 8, 2023 by pocster

[Pocster]

1 hour ago, Dillsue said:

PW spec says 5kw sustained 7kw short bursts so may be worth checking they dont mean collective export is 8.6kw when SE is at max??

 

There wasnt a note at the bottom saying you got what you want but warranty is now void

You made me bloody worry now !

I’ve email them again to change it to 5kw …. 🙄

[Pocster]

Tesla replied already !

Blaming me for telling them to set it to 8.6 - which I clearly didn’t !

Bit worrying that they don’t appear to check with DNO …. 🙄

[Pocster]

Now Tesla have replied ….

 

We cannot change the Powerwall export, but the total export, so it should be to 8.6kW.

 

oh ok ! But erm it’s 2 inverters - no understandy !!!!

 

[SteamyTea]

56 minutes ago, pocster said:

We cannot change the Powerwall export, but the total export, so it should be to 8.6kW.

Sounds like it only has 4 functions on it.

On

Off

Zero Export

Maximum Export

 

Now what other products you got in the house that have limited functionality.

[Pocster]

26 minutes ago, SteamyTea said:

Sounds like it only has 4 functions on it.

On

Off

Zero Export

Maximum Export

 

Now what other products you got in the house that have limited functionality.

What I really want with Tesla is use their predictive algorithm OR ignore it . Be nice to override it - or at least have it show you what it plans to do the next day . When it gets it right it’s great , but it cannot know if SWMBO will reenact a bake off episode or do 10 loads of washing - but I can .