Advice on new system please

[paul97]

Hi all

Your advice would be greatly appreciated. I’m looking to have a solar pv & battery with hybrid inverter installed. I have been quoted £12100 for the following and would like to know your opinions.

11x Trina Vertex S 425W Black Framed Mono
Givenergy 3.6kw inverter
Givenergy Gen 2 9.5kwh battery
And bird protection.

Many thanks

Paul

 

[johnb2713]

Get a bigger inverter, I sound like a broken record on this subject. With 3.6Kw inverter you will easily and regularly exceed it's capacity so even though the sun is shining and you have power in the battery, switching on the kettle and the toaster, oven + hob, washing machine etc you will end up, annoyingly, importing from the grid. If you install a 6kW inverter that wont happen with loads under 6kW which is a much better situation. Try if you can to get more battery capacity (they are available much cheaper than some installer's quote), you can then look at using some of the off peak tariffs to carry you through winter. Octopus intelligent for example is 7.5p off peak, I charge my batteries overnight if the weather forecast isnt favourable and then run the next day on this cheap electricity. My system a year ago was a similar price to yours (£12k) I took out a loan to purchase it and the system has saved more than the repayments evey month including through the winter.

 

[bladerunnerpv]

Hi Paul

That's the 3rd gen Givenergy inverter? The 5kW version, which is less than £100 more, will give nominal 5kW AC output (from PV), but still only 3.6kW from battery as per the 3.6kW inverter. Both have the same startup voltage of 150V.

How are they proposing to form the strings of PV panels, 1x11, 1x5+1x6 ? Do you know your roof pitch and orientation?

Suggest you have a search for PVGIS and you'll be able to get an indication of output, or easy-pv is another option. If you know your electricity consumption p.a. you'll be able to get an idea of how much the PV will cover. You won't get much from the PV in winter, that's when more battery charged on economy rate should help.

Suggest you take a look at immersion diverter too, e.g. Eddi, to use spare PV energy in summer to heat your water.

Enjoy!

 

[novelsmike]

Well, my system cost 10.9K plus another 1K for bird protection. 16 panels, 3 x 3.3 batteries, inverter etc. This seems to be the going rate. Just make sure your supplier is MCS certified.

 

[Mr Aargh]

1k for bird protection. What bird? An albatross?

Get optimisers on each panel. With the battery that should work out well to provide a lot of your needs. Also I agree re upgrading to the better givenergy.

Silly question but is there spare roof a different size of panel could address? Installers are generally limited to the ones they have in stock, a lot of the time. Those 425s are presumably quite large. Goodish though.

 

[binky]

1k for bird protection. What bird? An albatross?

Does seem a bit steep!

Get optimisers on each panel. With the battery that should work out well to provide a lot of your needs. Also I agree re upgrading to the better givenergy.

Optimisers are best avoided unless absolutely needed IMHO. They add twice as many connections on the roof and will fail before the panels, which have a life span in the region of 30+years. I'm not a fan.

Silly question but is there spare roof a different size of panel could address? Installers are generally limited to the ones they have in stock, a lot of the time. Those 425s are presumably quite large. Goodish though.

Installers don't generally stock panels, we buy from wholesalers who do that. Most installers just buy what is cheapest. 425s are generally a good spec, the higher wattage panels are not more efficient, just physically much larger. Always worth checking panel efficiency figures when getting quotes, along with low light performance. Everything works well on bright sunny days, not all work so well in winter conditions.

 

[Mr Aargh]

What I mean is smaller panels might fit more into the roof space depending on shape. I would not be without my solar edge optimisers as I can see the performance of each individual panel - and as they degrade it will not be at the same rate so the optimisers can help with that.

 

[binky]

What I mean is smaller panels might fit more into the roof space depending on shape. I would not be without my solar edge optimisers as I can see the performance of each individual panel - and as they degrade it will not be at the same rate so the optimisers can help with that.

You don't get much smaller these days, panels used to be 1.3m by 0.8m, which was good for double hipped roofs.

Out of interest, do you see much difference between the panels?

 

[Kot]

What I mean is smaller panels might fit more into the roof space depending on shape. I would not be without my solar edge optimisers as I can see the performance of each individual panel - and as they degrade it will not be at the same rate so the optimisers can help with that.

+1 for solaredge

 

[Mr Aargh]

Sorry - to answer your question, yes as I have two rooves facing south but at different heights and one is mildly shaded from one side for a short while in the morning.

 

[binky]

+1 for solaredge

I've had to replace several of their optimisers. They are mostly reliable, but not 100%

Locked to prevent hi-jacking (again)