Roof orientation and panels

Martyn1981

JKenH said:

ispookie666 said:

@michaels not sure if it's going to be financially viable.  if the production is rubbish, i might have to go down that route. The below pic is from our old house which supports how roof orientation will make a big difference (same day, 20miles away - 250w panels, Enphase 215 micro inverters 6.5yrs old). 


@Hexane it's a screenshot from Enphase interface, showing the energy generated yesterday per panel

I am intrigued by the difference in output per panel. Ignoring the 385Wh panel which presumably is in shade I see there is a variation of around 5% between best and worse panels. Looking at the  front roof on the current property there is a range of around 8-9%. Is this due to shading or do you typically see this type of variation between panels. 

I ask this because I seem to have a difference of around 17% between strings of panels on an unshaded roof and even greater in low light. I had a guy swap the strings round to check it was not the inverter playing up. (I don’t have solaredge so can’t see individual power outputs.)

Probably due to the small variance in panel performance, but could reflect some small shading issues that vary across the day.

One of the selling points for these systems is that they allow all panels to operate at max, rather than potentially being limited to the lowest power panel.

Ten years ago panels tended to be sold with a -5% to +5% tolerance, now I think it's typically 0 to +5%. So it's possible for that kind of variance, and whilst an additional bonus for these systems, probably not worth the additional cost for an unshaded system.

That 385Wh panel however does go to show the value of these systems, or the need to exclude that area*. I've got similar panels on both my roofs where they butt up against the central chimney that the sun effectively traverses through the day. [Edit, additional post suggests a problem with that panel, which ironically is another plus for these systems where a faulty panel doesn't hurt all generation.]

*Way back, when Solaredge and others were not well known, it was even an option to place a panel in that 'dodgy' position, but simply not connect it to the rest, so the aesthetics looked good, but without the drag that the shaded panel would have.

ispookie666

I'm glad with the decision to install as many panels I could.  Bulk of the generation is from 8am to 2pm.  The tree causes a lot of shading for 3 ish hours.  Might think about getting another single panel installed between the Front and Extension 1 to capture Solar irradiance in evening.  

NoobSolar

I would like to know about those emergency sockets - any more details?

ispookie666

@NoobSolar The installer just wired the Garage and Lights onto the emergency circuit.  This system is pretty much similar for most inverter manufacturers.  

When mains grid is present - everything works as it should.  The peak power will be limited by your inverters rated capacity for backup power.  When the grid fails, after a minimal delay the backup circuits keep going.  

This experience is from Victron Multiplus II.    I have not had the chance to test this with Givenergy.