Forums

Forums
Sustainable Sidetra...
Solar Photovoltaic ...
My 2.5kW array is o...
 
Notifications
Clear all

My 2.5kW array is only putting out 1kWh in an entire day

 
Solar Photovoltaic (PV)
Last Post by David999 1 month ago
3 Posts
2 Users
0 Reactions
122 Views
RSS
 David999
(@david999)
Honorable Member Member
1455 kWhs
Joined: 12 months ago
Posts: 302
Topic starter 04/02/2025 3:10 pm  

My 2.5kwp array is only putting out on a decent day about 1kwp in an entire day.  Seems the sun is just too poor right now.  I was contemplating doubling that this year but it seems pointless unless I want to balance my costs during the summer months on feed in tariff which is only 15p kWh.  I charge my batteries at 7p kWh.

Would I be better off installing another battery than more panels do you think. I then get a little longer when it’s 22p kWh.  

not sure where the break even is here,  better on panels or another battery.

 

anyone give some pointers please. 

This topic was modified 1 month ago by Mars

   
Quote
 Old_Scientist
(@old_scientist)
Reputable Member Member
776 kWhs
Joined: 9 months ago
Posts: 110
04/02/2025 5:01 pm  

I generated 6.4kWh on Saturday 2.8kWh on Sunday and 7.4kWh yesterday from my south facing 3.65kWp array - Saturday and yesterday were very good days with lots of sunshine.

I've just been considering a similar dilemma - do we add more solar (I could add another south facing 3.4kWp giving ~7kWp total) or do we add a 5kW battery.

We are on the Agile Cosy Tariff, so cheap slots for me are 12.86p and day rate is 26.22p. My average import rate is currently ~20p per kWh, so I figure shifting more usage from the 26.22p day rate to the 12.86p cheap rate may save me around 7p per kWh in winter and maybe less in summer. Very rough back of an envelope calculations tell me I may be able to save £400-500 per year for a 5kW battery system that is likely to cost me £4-5K to install, so likely to pay for itself over it's 10 year lifespan. I don't really see the investment case whilst SEG rates are 15p for exported solar and the difference between cheap rates and my import rate are only 7p per kWh.

Given current pricing, I'd be inclined to add more solar and just export as much excess as possible in the summer at 15p - view this as your annual 'battery' - using this to offset your costs later in the year.

Your economics are different as you already have a battery, and your margin (7p vs 22p) is wider giving you twice the leverage I have as 22p - 7p = 15p per kWh, so more battery storage may be better for you. Even in summer you can leverage the system by charging at 7p and using that during the day whilst exporting solar at 15p.

The main issue I see is that so much can change in the current pricing regimes over the lifetime of these products. The current 15p SEG rates could disappear or massively reduce swinging things towards battery storage to make the most of the excess solar you generate, which makes it really hard to price these long term investments.

This post was modified 1 month ago by Old_Scientist

   
ReplyQuote
 David999
(@david999)
Honorable Member Member
1455 kWhs
Joined: 12 months ago
Posts: 302
Topic starter 04/02/2025 9:55 pm  

@old_scientist no easy solution for this I think, with these battery banks being built to store wind energy I’m thinking as yourself that the FIT might go leaving me with loads of free solar for the grid.


   
ReplyQuote
Forum Jump:
  Previous Topic
Next Topic  



Share:

Join Us!

Heat Pump Dramas?

Thinking about installing a heat pump but unsure where to start? Already have one but it’s not performing as expected? Or are you locked in a frustrating dispute with an installer or manufacturer? We’re here to help.

✅ Pre-Installation Planning
✅ Post-Installation Troubleshooting
✅ Performance Optimisation
✅ Complaint Support (Manufacturer & Installer)

👉 Book a one-to-one consultation now.

Latest Posts

x Powerful Protection for WordPress, from Shield Security
This Site Is Protected By
Shield Security →