Mix & match PV panels OK? Installers Surrey?

[resybaby]

Oooh that link is just the thing i have been looking for, thanks both for sharing.

I am looking at extending my 545w JA Solar paneled system, as my invertor can handle another 1.6kw of PV. So thinking of adding 3 extra panels. Trouble is i cannot obtain the identical panels i have despite them being brand new just 6 months ago. Nearest equivalents are 565k JA Solars, so im thinking of stepping up for those additional three units, and wondered about the consequences. Article seems to say they will be 'down rated' to my existing 545w's, which is fine by me.

Also thinking of swopping out my 21 x 190w Upsolar FIT panels for 7 of the same 565w 'extra' panels, rather than end up with three different types on the same roof. Have done a few calcs and the 545w versions are giving such a big improvement in output, when compared with 190w panels, that i should earn enough cash from the remainder of my FIT contract to more than meet the whole bill for changing them.

Welcome to the forum Snuggy, some well helpful lads on here that really know their onions and are happy to help complete newbies like me to the world of PV. You've certainly found the right place to learn.

[resybaby]

I think I mean watts? But hey I was pants at physics so you guys lost me in the discussion above!!

Say for example could I have a row of large panels for example
JA Solar 565W (JAM72S-30-565-LR) and underneath another row of JA Solar 425W (JAM54S-30-425-LR-BF) This is simpler than what I am proposing but I want to know if they will work ok, or if I am better to keep to the same wattage panel and not maximise my roof space.

I am hoping to understand your next answer Thanks

Snuggy, my understanding of this question is yes you can do what you are saying. But it would be simpler to keep the two differing sets/rows of disimilar panels connected to their own MPPT point on your invertor. I.e. string the 565's on one string and the 425's on another.

[Joeboy]

I think I mean watts? But hey I was pants at physics so you guys lost me in the discussion above!!

Say for example could I have a row of large panels for example
JA Solar 565W (JAM72S-30-565-LR) and underneath another row of JA Solar 425W (JAM54S-30-425-LR-BF) This is simpler than what I am proposing but I want to know if they will work ok, or if I am better to keep to the same wattage panel and not maximise my roof space.

I am hoping to understand your next answer Thanks

Yes you can do this. Do you have an inverter in mind or is it still blueskying ideas? You would be looking to buy a dual string inverter. How many of each panel do you think you would like to fit? I think the recommended space between panel edge and roof end is still 200mm?

[Snuggy]

Whats an inverter?


No just kidding.
I was starting with the panels , when I know what the maximum I can get out of the system is I can go into that more, but I have had 2 quotes which want me to go for a 3.6 inverter which smacks of them not wanting to get involved in the G99. That is a battle yet to be fought I think

[John_S]

It may well be that the installers know that the DNO is likely to reject any request for a system which could export more than 3.68kW. Even without batteries, you can oversize the nominal output by around 10-20% of the inverter rating.

Are you considering batteries as well? That way, surplus can go into the batteries and be used or exported between dusk and dawn.

When choosing panels, you may also need to consider panel rating v panel area? The two JA that you are considering have virtually the same output per sq metre. If your roof is large, cheap less efficient panels may work out cheaper. Conversely, if you are constrained by roof area, more expensive and efficient panels pay be worthwhile.

[Snuggy]

if you are constrained by roof area, more expensive and efficient panels pay be worthwhile.

Yes probably need to go down this route. And yes a battery is definitely on the wish list

[John_S]

If you are considering adding batteries, it would be best to get a hybrid inverter now to which the batteries can be added.

I was an early adopter of solar panels and installed mine just as the generous FIT started. I remember that my preferred installer gave me two quotes one for more efficient Sanyo/Panasonic panels. The extra predicted income per the PVGIS extra expected output gave a 5% yield on the extra expense. That was good enough for me and it has improved over time with inflation.

[nowty]

Question (or puzzle) for you all,
How many strings can you see in this picture and I am not using any TIGOs. ?

5 maybe 6?

FYI Fintrary, sorry it was a bit of a trick question , there are actually 7 strings and 3 inverter / charge controller inputs. You fell into my dastardly trap of thinking 4a and 5a are in series.

Strings (1), (2) and (3) are in parallel and feed into a DC charge controller. Two different types of panels and different elevations but all have a similar voltage.
(1) 1a +1b
(2) 2a + 2b
(3) 3a +3b

Strings (4), (5) and (6) are identical single panel strings (Panasonic 60V panels) and are in parallel feeding into a second DC charge controller. In fact there is a 4th panel in parallel that is not shown in the picture because its around the other side of the house. All panels are identical but directions and elevations are all different. Note - standard single 30V'ish or 40V'ish panel strings could not work with a 48V battery system.
(4) 4a
(5) 5a
(6) 6a

String (7) is a more conventional higher voltage string feeding into a grid tie inverter.
7) 7a+7b+7c+7d+7e+7f+7g+7h

So my pearl of wisdom is,

Series strings need to have similar current (amps) rating and point in the same direction and elevation.

Parallel strings need to have a similar voltage (volts) rating but can point in different directions and have different elevations.

PS - Over 70 kWh generated today here at Nowty Towers and still generating.




PPS - And tomorrow looks like a fecking madman, maybe a PB.

[Fintray]

Question (or puzzle) for you all,
How many strings can you see in this picture and I am not using any TIGOs. ?

5 maybe 6?

FYI Fintrary, sorry it was a bit of a trick question , there are actually 7 strings and 3 inverter / charge controller inputs. You fell into my dastardly trap of thinking 4a and 5a are in series.

PS - Over 70 kWh generated today here at Nowty Towers and still generating.

PPS - And tomorrow looks like a fecking madman, maybe a PB.

Damn it, why am I not surprised!
That mash-up of panels is going to give Snuggy ideas that lead down the path of madness

[Snuggy]

What is the weather app you are using Nowty?

Thank you everybody who posted a sane answer to the original question.