String inverter with Optimizer or micro inverter for partially shaded roof

Hi, I have had two quotes both by leading solar companies who have suggested somewhat contradictory products for my proposed solar installation.

One says ‘don’t worry about string inverters, go with a micro inverter’, the other suggested that micros are not ideal and a string inverter with Optimizers would work best. Both were solar edge inverters. Our roof is mostly west facing and there is some shading at different times of the day. The company suggesting the string inverter with Optimizers advises 11, 365w panels can be fitted on current appropriate roof space, their competitor wants to fit 13, 300w panels with a micro inverter. We work full time only home on weekends and not looking at a battery at this point. Can anyone shed light on which might be best?

Hi @Lauren_Howells

This certainly is confusing, but it actually sounds like you are being sold the same, or very similar products, as opposed to contradictory ones. SolarEdge does not make micro inverters as far as I am aware. They use power optimisers, which work in a similar way to micros (panel level optimisation). Here is a review Jason wrote on the SolarEdge inverter system which should clear a lot up:

Please post photos of the actual quotes here, or the products models from the quotes so we can see what had been quoted.

Cheers
Marty

Thanks Marty, I think you are right and both inverters appear to be optimised inverters. the two inverter are SolarEdge s()000hd inverter and se5000H.

We have a relatively small roof space and some shading at different parts and at different points during the day but a good portion of the roof will be in full sun for most of the day. .

I’ve Also been quoted for two different sized panels solahart quoted for a se5000h inverter with 13x Solahart 300W (3.9KW) “SILHOUETTE” BLK PREMIUM solar panels; each panel fitted with P300 power optimizers and smart energy answers quoted for a s()000hd inverter with 14 x LG Neon R 365W ‘Star Performer’ Panels

I’d be really grateful if you would be able to confirm if these are similar units and which you might feel would be the better option…a bit confused and overwhelmed by the technology at the moment. I understand the LG panels are top quality but if the solarhart option is solid quality/output it might provide the better value better option as the LG is around $9000 upfront while solarhart comes in at 6700 interest free repayments over 60 months.

I’m leaning towards solarhart because the solar will start to pay for itself upfront…help!

Hi Lauren

We aren’t really sure who manufactures the SolaHart panels. Jason looked at one spec sheet and it seemed to be a rebranded Q Cells panels, which are good, but they may rebrand other manufacturers panels too, so it’s hard to know how they compare. We have confidence that LG is really good though.

The SolaHart quote you are getting 3.9kW of PV vs 5.1kW with the other quote. That’s quite a difference.

I can’t tell what this other SolarEdge model is - s()000hd does not seem to be a model number. The () seem to indicate that a size should be inserted there. I’m assuming it’s the same model that SolaHart quoted you (5kW model).

The main advantage with the SolaHart options seems to be that they are including optimisers, but the other quote isn’t. Depending on the shading of your roof, that could be quite beneficial.

I know you are leaning toward the SolaHart quote, but you are getting a considerably smaller system. I would personally prefer the 5.1kW of LG panels, but like you say it’s a big difference out of pocket. Although “interest free” deals from my experience usually mean a higher price up front. There are options of financing the other system though. This article gives a pretty good insight:

I would probably go back and get a couple more quotes personally. I like SolarEdge and LG, but I would have thought you could get a more competitive price. Have you checked the solar price calculator?

What area are you in?

Cheers
Marty

After much debate, I ended up going with a microinverter setup instead of the power optimizers. The cost up front is a little more, but it has several advantages. We all like to think the gear will just work forever, but things can go wrong. With a string inverter, you do have a single point of failure which brings the entire system down. With the micros, I have 16 panels, lose an inverter or a panel, and I lose just 1/16th of my power production. The DC voltage on my roof is always under 40 volts, and the AC from the micros is normal household 240 volt split phase. On a string inverter setup, even with the optimizers, you have u to 500 volts running around the roof. If a connection breaks, it can arc and fires have been caused by this. The power optimizers from Solar Edge are very good and much safer than typical string inverters. They should be able to cut the power very quickly if a break is detected, but high voltage DC will strike up an arc very fast. The 40 volts from a single panel won’t, and the 240 volt AC is far less likely to maintain an arc compared to DC.

I have some bad shading issues due to palm trees that I need to have trimmed AGAIN. The Micros do a great job of getting every bit of power out of even those shaded panels. Late in the day when the panels in clear sun are dropping fast, the shadow moves off the lower panels and they start making more power for the last 2 hours of sun. The optimizers will also help in a situation like mine, but when 4 of the 16 panels are fully shaded, it may go out of range of what they can optimize. With the micros, that is not a concern, every panel is on it’s own to pull as much energy as possible.

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