Hoodwinked in to expensive, underperforming PV system

[HellDiverUK]

Hi folks.

Just wondering if I can get an opinion about the system I had fitted in September 2013.

System as follows:

SunnyBoy

SMA SB5000TL-21​

fitted in attic
Tigo optimisers on panels, and Tigo "box" that links to the internet
20x ET Solar

ET-P660250​

panels


Install is as follows:

8x panel on front of house (NE facing)
12x panel on back of house (SW facing)

Charged: £10,300.


So, yeah, you've probably noticed the first issue - NE facing roof. Yep, that was the first hoodwink. Yes, they'll produce fine they said. They'll catch the morning sun they said. Turns out they're as pointless as you expect - unfortunately we didn't do our research and signed the dotted line. The front panels will never pay back over 20 years. As it is, the back panels are performing well, shame they're having to carry the fronts.

The Tigo stuff, well that's a farce.
There's a box in the attic beside the inverter that connects to the internet and transmits data to Tigo's web site. Except the data on the Tigo site doesn't correlate with what the inverter and the generation meter say. The generation and Sunnyboy agree. As of today, the Sunnyboy is reporting 892kW generated, Tigo is saying 947kW. I'm not convinced whatever the Tigo stuff is doing makes it worth the £1000 charged for it.
There were small Tigo boxes on the panels, I assume those are micro inverters? Maybe someone could explain what they do?

The install quality was terrible, too - they fitted the mains isolator overlapping the electric meter, so when the electricity company arrived to change the meter for an import/export meter, he was going to walk off site as he couldn't get the old meter removed. I shifted the box myself while the OH made the guy a cup of tea.

So, after that disaster, we did a LOT of research, and we know we were conned.


On the other hand, another company fitted a 6.5kW system to the OH's parent's house, also with a SB5000TL-21, and 26x Renesola panels, Immersun, and had change from £9k, and they did a WAY better install job. It's a ESE facing roof, and it's performing excellently.

 

[SolarCity]

When you say north east, is it directly facing that way? No reason why those panels shouldn't be doing reasonably well, although it is debatable whether it was actually worth considering this roof space in the first place. Particularly as in doing so you have pushed into the 4-10kWp FITs bracket rather than the 0-4kWp bracket.

 

[Gavin A]

NE roofs can be worthwhile as a second string to SW roof or similar depending on the slope angle, providing the price is right on it, but see the main benefits through the summer when the sun actually gets round that far, so the 6 months from September won't really do it justice at all.

The TIGO will be reporting the DC generation, the Sunnyboy and meter will be the AC generation, with the 5% or so difference being the inverter losses, but yes IMO they would be a waste of money.

We'd probably have gone with a 3600TL as being better matched to the actual peak generation levels, and charged more like £7-7.5k for the job vs around £5.5-6k for the front roof only, so at those sorts of price differentials the NE roofs can make economic sense, £10k is too steep in my book even with the TIGO units, though they would add a fair bit to the costs.

 

[JulianC]

Hmmm, 892kWh since September does seem rather low. My own system (a lowly 3.7kW) has clocked up 815kWh since it was fired up on September 5th. It is less than ideally located and suffers from shading over the winter months.

 

[HellDiverUK]

Hmmm, 892kWh since September does seem rather low. My own system (a lowly 3.7kW) has clocked up 815kWh since it was fired up on September 5th. It is less than ideally located and suffers from shading over the winter months.

I didn't think it was running terribly well. The new 6.5kW system on the inlaw's house seems to be performing WAY better, just using two 13 panel strings.

 

[HellDiverUK]

We'd probably have gone with a 3600TL as being better matched to the actual peak generation levels, and charged more like £7-7.5k for the job vs around £5.5-6k for the front roof only, so at those sorts of price differentials the NE roofs can make economic sense, £10k is too steep in my book even with the TIGO units, though they would add a fair bit to the costs.

Yeah, they were looking £11k with a voltage optimiser and an Immersun - we told them we weren't interested in the voltage optimiser, and our heating system is a combi boiler (not common here in the wilds of N. Ireland).

Pack of hoods to be honest, still kicking ourselves that we were sucked in by the sales woman, and should have walked away when the 'engineer' came out to do the survey and hadn't a clue what he was talking about and had to go to his van to talk to someone in the office every few minutes! :censored:

 

[Gavin A]

Hmmm, 892kWh since September does seem rather low. My own system (a lowly 3.7kW) has clocked up 815kWh since it was fired up on September 5th. It is less than ideally located and suffers from shading over the winter months.

they've only got 3kW south West though, 2kW nowth east, and in northern ireland, so I don't think it's necessarily underperforming what I'd expect in those months, particularly given the weather.