Tigo vs SolarEdge for heavy shading?

hi - have got quotes for 6.6kw solar (18 panels) - our consumption 20-25kwh per day. looking for value for money soln. On my north facing, pool heating is there so combination of west and east was considered as suitable location for panels. However, on my west roof, half the roof is shaded due to tree next to the house. The shading doesnt has much bearing in summer however will likely have material impact in winter/autumn including some on east side.

Two installers I spoke to suggested going for solar edge or optimisers to provide for the shading. I was thinking of having two separate strings so that the panels on the east can generate in the morning and the panels on west in the afternoon.

After reading the blog on solar edge - requiring minimum 6 panels not to be in shade - am not sure my above configuration of 2 separate strings for east and west works.

Open to suggestions on layout of panels and whether solar edge/enphase/tigo optimiser will work better.

Hi @diksychick

I’m happy to be corrected here, but I reckon by the time the sun gets around to be behind that tree, your solar generation for the panels on the east roof will be largely over for the day anyway. That is to say, when you’ve got panels facing east, they will get maximum generation in the morning when the sun is in the east. You will still get decent generation when the sun is in the north, but by the afternoon, I reckon you’ve only got a small amount left, especially in the winter when the sun is low in the sky (and when the shading is the worst. In which case, I wouldn’t even be too worried about panel level optimisation (SolarEdge or Enphase). It would definitely help to a degree, but given the fact that your roof isn’t ideal for solar (even the east roof is a bit south unfortunately), and there’s nothing any inverter can do about that, I would be more concerned about squeezing as many high efficiency panels on as possible. I would also suggest oversizing your inverter, because you’ll never get the maximum potential out of your panels.

I hope that helps.

Cheers
Marty

Thanks Marty. Thats right - the east panels will only produce till say early afternoon.

The pictures above show east panels only but i am thinking of going 9 panels east and 9 panels west. West panels will be towards the back of the roof after whirly bird. In summer, there is no shade on west side however in autumn/winter there is shade on west side that moves between couple of panels to most of panels shaded and last couple of hours. For these panels on west, i was advised to use Tigo optimiser atleast and if possible go for solar edge.

Sorry if it wasnt clear before. With the above context, what wud you recommend?

thanks so much

Ah ok, apologies, I misunderstood.

6 panels on the west would probably work, but like you say, is it worth getting SolarEdge for that scenario given once the shade hits any panels on that string, the voltage will probably drop too low and the inverter will drop out anyway? It is hard to say. It’s probably worth getting panel level optimisation, Enphase ideally, but Tigo or SolarEdge is fine. The nice thing about panel level optimisation is that you’ll know exactly what is going on, whereas with a string inverter you’ll be in the dark, along with your panels.

If you can afford the upfront cost, it’s probably worth it in the long run.

Hope that helps

Marty

ok thank you. I have been suggested 9 panels each on east and west.

In choosing Solar Edge - is there a preference for P370 or P404 optimiser? Is one more reliable than the other or preferable for shade scenario. I heard conflicting views from installers.

For Tigo, the combination is with growatt inverter and Tigo is only on west side i.e. 2 separate strings. Is there any compatability considerations?

Also, are the rails important consideration i.e. Titan vs clenergy - any preference.

thanks Marty. I was finding, solar is not that straight forward decision.

No, it rarely is straight forward unfortunately, but this is a trickier installation than usual.

To be honest, it’s bloody confusing stuff, you would need a SolarEdge guru to guide you through this one. SolarEdge doesn’t seem to supply a clear guide as to when to use these different Optimisers publicly, I’m sure they have detailed training documents about it though. I’ve been reading through MC Electrical’s review of SolarEdge again, and toward the bottom he highlights how difficult it is to get this sort of installation right.

I would defer to MC Electrical for this install and go with the Tigo optimisers. MC states in the below article:

TIGO OPTIMISERS ARE BETTER IN SHADE

In my SolarEdge post, I showed how SolarEdge usually requires a minimum of 8 panels to operate efficiently. This is because the SolarEdge inverter requires a combined 360 volts from all the optimisers, and standard optimisers only boost to a maximum of 60 volts. If you have less than six panels un-bypassed, the inverter will go offline. In short, the SolarEdge system does not work well in heavy shade.

That’s right, it would need to be two separate strings, and just having the optimisers on the west roof is cost effective way of doing it.

I wouldn’t say it was overly important. Clenergy is a more premium option that Titan - the Clenergy racking system costs about 10% more. It’s a relatively small proportion of the overall cost, if you’ve got the choice, I’d suggest you might as well go with Clenergy.

Hope that helps.

Cheers
Marty

Thank you Marty

Fingers crossed it works well

Hi @Marty

On the final leg of choosing on options - finally decided to go with SolarEdge and will trim tree depending on how it goes.

Question on choice of panels - i hv been quoted few panels - almost same in price

  1. 20 Ă— 330W JA Solar PERC Half-Cell Module
  2. 18 x Canadian Solar 370w CS3L-370MS
  3. 18 x Jinko Solar Cheetah Plus HC JKM370M-66H

Which one would you recommend? The installer prefers #1 based on his installation experience.

thank you so much.

Hi @diksychick

I find these pretty hard to split. Similar technologies, and the companies have a similar reputation.

It looks like a coin toss to me. If the installer is keen on the JA’s, I think they are as good an option as the other two.

Cheers
Marty

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