Best inverter choice with shading issues | Enphase, Tigo, SolarEdge, SMA shadefix

[aquaboy]

Hi
I’m currently going through some quotes for 7.4 - 8.2kw systems. I have some minor shading issues on my Northern roof (particularly before 10am and after 4pm and more pronounced in Winter) and its been suggested I split the panels between the Northern and Western roof, which has no shading issues. I was going to use a single inverter but am worried it may not be suitable for this. The salesman has said the panels would be on two separate strings? I’m looking at a Sungrow 8kw inverter. I’m not sure if I should go for micro inverters which will be much more expensive?

[aquaboy]

So I’m comparing quotes:

1. 25 Q cells 330 and 8kw Sungrow inverter $7990
2. 21 Jinko Cheetah Black Frame and 6kw SMA inverter $6575
3. 23 Seraphim 330 and 6 kw SMA inverter $5950
4. 25 Trina Honey and 8kw Sungrow inverter $7400

What do you think?

[Marty]

Hi @aquaboy

Regarding the shading consideration, it would depend on the specifics as to whether a Sungrow would be ok, or if you should go with a micro inverter/optimiser setup. Do you have some pictures of the designs that the solar companies are putting forward, i.e. where the panels will go on your roof, and the extent of the shading issue?

Regarding the sizing of your system. You’ve got a couple 6kW quotes and 8kW quotes. What are you trying to achieve with your system, offset your current usage, eliminate your bill , or produce as much solar as possible? How much electricity do you currently use?

Regarding panels and inverters, it depends on what you are wanting to spend. Do you have a budget? What model is the Q Cells? I’m assuming Q Maxx? Whilst I’d be happy with a Sungrow inverter, I’d personally probably go with SMA and Q Cells (but Q Peak if it’s an option). Jinko Cheetah is ok as well though, what wattage are the Jinko panels? Of the 4, number 2 would be my preferred.

Where abouts are you located?

Cheers
Marty

[aquaboy]

Here’s some pics of roof shading issue.

The first is in the late afternoon about 4 pm. Of concern are the palm trees. The second is early, about 10 am, the shadow from a gable roof next door. These are taken in the middle of winter. In summer I doubt there would be any shade to worry about. So the plan is to put half the panels high up on the northern roof and the other half on the western roof, which has no shading issues a all.
Regards
Robert Hickey

[Marty]

Hi Robert

Thanks for that. Yes, looks like plenty of shading going on on the north roof. If the west roof is clear, that would be make sense to maximise roof space there. The west roof usually yields 10-15% less than the north in perfect conditions, but if you oversize the inverter with panels lower yields don’t really matter so much anyway.

As for whether you would need micros or optimisers, that would depend on how many panels you could get on the north roof comfortably out of the way of any shading issues. A Sungrow inverter would allow you to put panels facing two different directions (it has 2 x MPPT inputs, as long as there is enough panels on both roofs to meet min voltage levels).

The other option besides Enphase that is very much worth considering is Tigo optimisers. Tigo allows you to have the best of both worlds - it is inverter agnostic, so it can be used with Sungrow, and it can be deployed only on the panels that you have shading concerns making is lower cost. So you might have 8 panels in question on the north roof, you can get Tigo optimisers just for those panels, which should keep the cost much lower than going full Enphase.

Tigo Solar Optimizer

Hi, I have been quoted 6.6KW Solar panel system to be installed at my place. I currently have 1.5KW installed. The installer recommended adding Solar Optimizer to the new Solar panel system. This is due to shading issue. My next door neighbour is two-story house and some trees around the house. The installer said if I don’t want to pay more for the solar optimizer, they can remove the old Solar Panel system (1.5KW) and install the new solar panel on the current location. I will save more because…

However, as you’ll see in this thread, there are a number of installers who think that Enphase micro inverters will give you the best financial return over a long period, so if you have the ability to pay the extra up front cost, you may be better off in the long run due to higher performance.

Micro inverters (Enphase ) Vs Power optimisers (SolarEdge, Tigo)

I recently received this advice from a supplier I asked for a quote for my situation in a shaded area, regarding Optimisers Vs Micro inverters. reply is as follows: Using an inverter technology like SolarEdge with optimisers behind every panel, or even using a string inverter like a Fronius with TIGO optimisers behind every panel, still have a weakness when compared to Micro inverters. Optimisers work well when some of the panels are shaded, but in order to continue functioning, they always ne…

The final thing I’ll mention is that SMA advertises ShadeFix optimisation built into their inverters, which I’m hesitant to recommend as this is mainly a software optimisation, and I’m not sure if this is simply a good marketing spin on what most string inverters do anyway, or whether it actually works better than other string inverters. I think what is clear though is that it certainly won’t work as well as panel level optimisation (i.e. Enphase micros, SolarEdge and Tigo optimisers).

Hope that helps.

Marty

[aquaboy]

Thankyou so much for that info.

I’ve decided to go with a Sungrow 8kw inverter and 25 Trina honey blacks, with 9 on the western roof and 16 high up on the northern. I’m convinced they will have no shade. The quoted cost all up is $7350. Does this sound reasonable? I have a large 5 bedroom house with a pool and ducted air cond. I also hope to install a pool heat pump in the future.

Regards.

[Marty]

Nice one Robert, yeah I think that price is reasonable