discrepancy between total on generation meter and that on Tigo monitoring

[series530]

Don't know with Tigo but with Enecsys the differences can be huge. As usual, I'm at the other end of the country and cannot access my spreadsheet: I've been compiling a comparison between the PV meter and the EnviR and the PV meter and the Enecsys website day by day. Provided the smart bridge doesn't freeze on the EnviR system the error between it and the PV meter is about 1 to 2% under all weather conditions. Contrast that with the Enecsys system whereby on a reasonably sunny winter day the error is about 3% and on a cloudy day with a low harvest it can be off by anything up to 150%. The problem is that the monitor seems to have poor performance at low power and absorbs most of the produced energy to drive the inverter. What ends up reaching the PV meter is piffling compared to what it claims to have produced. Overall though, so far, the Enecsys system is reading about 6% higher than the meter but I expect that gap to reduce as the summer comes. Tigo may suffer from a similar problem?

 

[SolarCity]

Sounds like the Tigo system may suffer from the same problem.

 

[Nutmeg2]

This is what Tigo had to say:
'Thank you very much form providing us with this information. The readings from the inverter and the generation meter are very similar and also reflect the expected amount of energy that your systems should have been generating.'
and:
'The information from the Tigo system is higher because this system is reading the energy generated directly from the Solar PV panels, however the system would have some losses on the cables and inverter. Therefore, the energy coming out of the inverter is the actual usable energy and the one being reading on your generation meter.'
Sounds to me like their usual fob off.
She is waiting to hear what her installers say.
Is a SMA 2500 invertor the right size for her 10 x sanyo250s?
I have a SMA2000 for 10 x sanyo 240s facing West with litle/no shading probs.

 

[fiardor]

I have done one tigo system and it was a while ago but i am sure certain parameters have to be inputted correctly when registering the system online.

Just a thought.

 

[SolarCity]

Both of those inverters seem fine for the systems you have installed.

Personally I would go for the HF models if I was to use the SMA range as they offer better efficiency. I very rarely use anything that isn't TL or HF at the very least.

 

[Nutmeg2]

That's a relief - thanks!
Mine is certainly HF; hers probably too as same firm installed both systems

 

[LiftMan]

HI. I have a tigo system installed end of last year. I take regular readings and initially the Tigo records were 13% above generation meter. The inverter was 2% higher.
I questioned the matter with Tigo and got a similar reply to the above. Tigo measures at source whereas meter is fact.
After several months the difference has now dropped to approx 8.5%. To be honest I was a little annoyed however I compare output with several freinds and despite me suffering a lot of shade, particularly early in the year, I am doing very well. At times even beating systems that appear to be better located.
Stick with it but would recommend MPPT scan on inverter is switched off (with installers agreement).
Hope this helps.

 

[Nutmeg2]

Friend's discrepancy now much lower - obviously related to season. Her panels doing very well overall, often better than mine (similar orientation but little shade).

 

[danesol]

Well I have 5kw more now on the OFGEM meter than the SMA Inverter :17: