Can I DIY solar panel replacement?

[Andeh]

We have a bungalow with a large shallow roof, with 21 x 195w panels from 15 years ago. I'm up on the roof in a regular basis gutters, Christmas lights,cleaning panels etc etc.

 

We are also on an early tariff at 85p/KW rough FIT from memory.

 

We also have a 4kw PV inverter.

 

I was thinking, how hard would it be to replace 2 panel's with brand new 450w ish ones to up our output without incurring excessive up front cost?

 

I recon I could fit 2 new ones and still be within the 4kw limit, with just how old and inefficient the existing panels are and the fact it's a 13degree roof so sub optimal? Even in the very best generation days in the last few years I've never seen a generation of more then 1.8kw peak.

 

Any thoughts? Thanks

 

 

 

 

Edited 2 hours ago by Andeh

[markc]

Parts need replacing when they break down, what’s stopping you “repairing” your system with modern components.

[ProDave]

Be careful.  A FIT system is registered with the design power.  If you add to it, there is a complex way of declaring the addition and only a portion of what is generated is then paid.

 

You could add extra panels and another inverter that is completely separate to the existing system, the procedure for that is a lot less complicated.

[Dillsue]

At 13 degrees your roof will likely be below the level where the panels are self cleaning so you'd probably get best results by setting up an automatic cleaning system that sprays them once a week.

 

You can change out the panels if you want but you'll likely need to extend the mounting rails so factor that in. If the total generation capacity goes over the FIT registered capacity you need to let your FIT payer know and they'll pay you the proportion of generation attributable to the original capacity only. You won't get FIT payments for the extension!

[Dillsue]

3 minutes ago, ProDave said:

Be careful.  A FIT system is registered with the design power.  If you add to it, there is a complex way of declaring the addition and only a portion of what is generated is then paid.

 

You could add extra panels and another inverter that is completely separate to the existing system, the procedure for that is a lot less complicated.

An extra inverter on top of an exiting 4kw unit would need a G99. Might be easier to let your FIT payer know about the extension as thats just a phone call/email??

[trialuser]

There is loads of info on the internet about using mismatched panels, presumably in series, apart from the fit aspect you need to consider the electrical side.

It may be the case that your existing panels pull the output of the new panels down considerably and you get little benefit. You also need to consider the max input voltage for you inverter if the new panels are significantly higher.