SMA or Aurora: System Design

Decisions SMA vs. ABB vs. Fronius

In my previous blog I explained why going with ABB’s inverter or SMA’s Sunnyboy was a great choice if you are looking for an inverter that will go the distance and is backed up by a trustworthy warranty if something goes wrong. This blog takes it a little deeper, examining design choices that will make a difference.

Update. To get my view today on ABB, have a quick read of the Bold sections. We no longer supply ABB inverters. If you are looking for my latest recommendation, have a look at my Fronius Inverter Reviews. or my new ABB UNO Review (2017)

A good design is paramount to the best performance of your system. There are so many factors that come into play: load profile, roof-line, shading, orientation, utility restrictions, CEC regulations, aesthetics and of course, budget. So when it comes to designing a great system, inverter flexibility is a designer’s friend.

(This blog presumes we are designing with the current industry standard panel: approximately 260 watts, 40 volts, 8 amps.)

Scenario 1UPDATE: The ABB specification on the CEC website are updated every Friday. At some point they changed to 4.6kW so this point below is no longer valid…. this following point is no longer valid. MC Electrical now supply the Fronius International inverter so we can legally install 6.5kW of panels on it. This was the point:   Again you have a big roof-line, and you want to put more panels on your 5kW inverter than just 5kW. This way over the course of the day you will produce more power (which gives you the best bang for your buck). Energex are fine with this, and CEC Regulations allow us to put 33 percent more power into the inverter than it outputs. So from the figure above: -The Sunnyboy 5 000 TL gives you 4 600W נ1.33 = 6kW -The Aurora PVI 5000 TL gives you 5 000W נ1.33 = 6.5kW. Aurora wins again.

Scenario 2. Let’s say you don’t have a huge roof and you want to split your panels: e.g. 16 panels facing North and 6 facing East. – The Sunnyboy 5 000 TL will restrict the output of your northern panels to 15 amps, when they want to reach about 16.6 amps. -The Aurora 5 000 TL will take it in its stride. This is starting to look bad for SMA!

Senario 3. Your roof is just a little more limited. Let’s say you can only put 4 or 5 panels North and the rest West. – You can’t do this with the Sunnyboy 5 000 TL as the voltage window is too low. – The Aurora can do this, and we can internally wind the voltage down to suit the unusual setup. 4 out of 4 to Aurora!  UPDATE: I was given grief for this claim on whirlpool. So I reconfigured our showroom ABB  showroom to run on 2 strings of 4. It runs at about 96 percent (per watt) of the SMA that is configured in a string of 12. If all you have is additional space for strings of 4, then work with what you have!

Scenario 4. Let’s lower the bar. You only want to put 4.5kW on your northern roof. Or you want to put 2.5kW East and 2.5kW West. -The Sunnyboy 5 000 TL can do it with no performance losses – but you will pay more because “SMA is the world’s number 1 inverter”…. apparently. -The Aurora PVI 5 000 TL can too – and is cheaper than the Sunnyboy 5 000 TL.

Scenario 5- You want the bells and whistles just because you can!

Updated February 2016. Since writing this post, ABB came out with a retrofit wifi. It was a bit glitchy but now seems not too bad. The Fronius Symo and Primo inverters come inbuilt with a data manager. The Fronius SolarWeb platform and the Smart meter combination is second to none. SMA or ABB don’t even get a look in. We currently have 201 (and growing) systems that we have connected to solar web. Around 20 of these have the Fronius smart meter attached.
You want an inverter with Bluetooth? Go SMA (but hard-wiring is better if you want to analyse data and both inverters offer this). -You want an inverter that currently has a retro-fit solution for hybrid? Go SMA (but Aurora can be easily linked to a top quality 3rd party solution). -You want a user-friendly screen interface? Go SMA (but Aurora offers far more information for the electrician or for the tech savvy). -You want an inverter that’s made in Germany? Go SMA (Aurora is made in ITALY and US).

Don’t get me wrong, the SMA is a fine inverter, but as you can see here, ABB (power-one) Aurora has significant advantages for design flexibility. UPDATE: The reason we have moved away from ABB is mainly due to a massive failure rate. At a quick look at our invoicing we have invoiced ABB to replaced 54 Abb inverters in the since October 2015 (6 months). That’s one inverter replacement every 3 working days. ABB come to the party and are good with their warranty replacement procedure. But for obvious reasons, we no longer supply ABB Aurora inverters.

Mark Cavanagh

Leave a Reply

Your email address will not be published. Required fields are marked *

Mark Cavanagh

Mark is the Owner and Manager of MC Solar & Electrical. He’s an Electrician, accredited solar installer/designer and an electrical contractor.

Get A Free Product Tour

Visit our showroom in Eagle Farm, Brisbane and discover what’s possible for your property.