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Replace 2.5kw system help


dave1967

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Hi

We are reroofing so our 2011 panels need to come off and as they are badly fitted and an eyesore we are going in roof. Can anyone help with a solar company who can supply. I can get 8 ja 325w panels for £850 but they cant supply the fittings and mountings . We dont want to pay more than £1500 if possible. Any help appreciated.

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1 hour ago, dave1967 said:

Yes they are but i have read as long as they are the same kw it is not an issue.

That's interesting, as I'm in a similar position. Do you have a link to the documentation?

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That was from ovo. But they advised to check with ofgem who said what they say is not legally binding however as long as all the plant is not decommissioned up to the grid it should be fine. So a swap for repairs or cosmetic should be ok. It also says this on their website.

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4 hours ago, dave1967 said:

That was from ovo. But they advised to check with ofgem who said what they say is not legally binding however as long as all the plant is not decommissioned up to the grid it should be fine. So a swap for repairs or cosmetic should be ok. It also says this on their website.

As post above, OFGEM changed the rules in Dec 2021 and loads of places I've seen don't reflect theses changes. Someone sent me link recently to a Guardian reporter saying you can't change anything which isn't what the OFGEM guidance says!

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Yes, OFGEM have bowed to the inevitable and finally acknowledged that much old FIT eqpt is nearing the end of its life and the identical like-for-like replamements they used to insist on are simply not available any more. Current guidance is much more realistic including the apportionment rules if capacity is changed.

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On 26/09/2024 at 10:51, dave1967 said:

Hi

We are reroofing so our 2011 panels need to come off and as they are badly fitted and an eyesore we are going in roof. Can anyone help with a solar company who can supply. I can get 8 ja 325w panels for £850 but they cant supply the fittings and mountings . We dont want to pay more than £1500 if possible. Any help appreciated.

Just noticed the price your quoting for 325watt panels....£100 each seems very expensive!!

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3 hours ago, dave1967 said:

I thought that 100 each was ok. Change of anyway 6 420 will fit the roof better so going with them.

CEF we're selling Longi 405s for £52 earlier this year. City Plumbing have 410s at £56 just now

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  • 1 month later...

Evening

Got the new panels

6 x dmarc 410w

Now have another problem as they may not have enough voltage to kick start my 2 sunnyboy inverters. Didn't kick in between 3 and 4 on a dull day. Is a new inverter the answer?

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The panels, string design, voltage and amperage would have been designed to match the inverter specifications.  

 

What panels did you have before?  What were they rated at? How many panels in a string?  (presumably 5 each but not necessarily)  

 

What is your string voltage and amperage now?  Is the polarity correct?  A string of six panels should have an open circuit voltage of 120 - 225 v and 10-15 Amp depending upon panel specs which should be fine on one of your SB1200's.  These things are bullet proof, but keep the other one as a spare.  

 

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Who has installed the panels?  What are their qualifications?  Are the clamps within the clamping zones of the panels?  Have you run uplift and dead weight calculations to ensure the correct number of fixings and screw sizes to work with your roof timbers?  Distance from roof edges and ridge?  If the installation was poor before, did the original installers properly assess the roof structure?  Most times not. 

 

[Back in those early cowboy days we turned down installs on some roofs rather than risk roof damage or panels flying off.  Often the homeowner would call back later to say company 'XYZ' had fitted 'twice as many panels' as we had recommended but had gone out of business.  We had quite a good business fixing all the badly installed panels during the solar crash...]

 

Who is connecting the panels to the inverters?  What connectors are they using?  Are they original manufacturer or 'generic compatible' with the original connectors, (MC3 or MC4 depending upon the age of the inverter).  NEVER mix and match connector types - there are plenty of examples of fires caused by incompatible 'compatibles'.

 

What size cables? Are they double insulated and how do they enter the roof space, (are they mechanically protected, or just run under a tile?  

 

 

 

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The issue is i have 3 panels on each inverter so the installer said they are not getting to required start up voltage. So i need more panel or a new single inverter.

No idea if this is correct.

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Yes. Who designed this system for you?

 

Is the 'installer' a MCS competent person?  If not, what are their qualifications for installing panels and working with high voltage DC?

 

Why did they not check the requirements before connecting to the inverters?

 

 

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You don't necessarily need a new inverter or more panels.  6 panels should fire up a single SB1200.  Whether it will make the most efficient use of the panels, who can say.

 

For maximum returns, a PV system should be designed, not just thrown together.

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The issue is i have 3 panels on each inverter so the installer said they are not getting to required start up voltage. So i need more panel or a new single inverter.

No idea if this is correct.

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If it were my panel on my roof I'd connect the two strings in series, then connect to one inverter.  I'd have a bit of extra inefficiency from the additional cable length, but if I couldn't get on the roof to re-string it'd be the easiest option.  

 

However, I'm stating ON RECORD that I DO NOT recommend that you do this.  It appears neither you nor your installer are competent enough to install panels or connect high-voltage DC to a grid-connected inverter.  

 

My recommendation is to have a suitable qualified PV installer commission the system for you.

 

 

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