3 panels east 3 south, Tigo Optimisers and their reliability.

[ChrisJEvans]

I'm self fitting 15 panels, 12 facing south and 3 east.
I'm told the 6K inverter I've ordered needs at least 5 panels on each string
So I plan on having one string with 3 east (on a pitched roof) and 2 or 3 south (flat roof)
One installer told me I only need to put optimisers on the East facing panels but surely I need them on all?
At midday wouldn't the East facing panels limit the South panels and in the morning the South facing panels limit the East?
or have I misunderstood how optimisers work/are used?

Tigo Reliability
One installer said they won't use Tigo optimisers due to unreliability. So I'm trying to work out a way of fitting them and being able to change/bypass them easily.
Three of the panels will be on a pitched roof and three on the flat roof. The flat roof can be easily accessed. For the 3 pitched roof panels I was wondering about feeding both panel cables into the loft via extension leads if necessary and fitting the optimisers there. Most panels seem to come with one short captive cable and one long but the datasheet for the panels I've ordered (and should be collecting tomorrow) says both cables are 1.2m long. If I have to add extension cables to one or both of the panel cables it would add three or six extra connections and 3m cable length to the six panel string how significantly would this effect performance and reliability?

Any thoughts and suggestions very gratefully received.

[Stinsy]

I’ve never heard anything about Tigos being unreliable, in fact I’ve never heard of a single failure. Mine are going strong after 3 years.

Number of panels is irrelevant it is string voltage (Vmp and Voc) and the inverter’s MPPT range that are important.

If I were you I’d do 6x south-facing panels on one string. And have the other string with 6x south and 3x east facing with Tigos on all 9.

More than one way to skin a rabbit though. However you need to ensure that the string voltage is high enough even when the Tigos are doing their thing.

It’d be much easier to help if you posted the specs of the panels and inverter.

[Oldgreybeard]

Same here, not heard a thing about poor reliability from Tigo optimisers, or any of the others come to that. I suspect that the installer either has duff gen about them (all too easy with the way false news circulates on social media) or has a problem getting hold of them at what he believes to be a reasonable price.

[AGT]

Check the minimum operating string voltage on the inverter and the PV panels voltage to see what you can do.
It maybe more cost effective if you need to borrow one of the PV panels on the other roof to physically fit it on that roof but cable it to the other string?

[nowty]

I've been running several TIGOs for about 3 years. The great thing with them is you only need them on the mismatched or shade problem panels. And you can make up some really wacky string configurations with combinations of different panels and orientations.

You just have to understand how they work to design an overall topology of a string. They attempt to match the natural string current and sacrifice voltage to do this, and they don't work without the help of a string inverters MPPT.

They are generally very reliable, I have had one failure, but it is a DUO (higher Power version) and I have been running it on two mismatched panels in parallel which are in series on a longer string. Although I am not exceeding the power limit of the TIGO It quite often runs up to its own 12A current limit and runs hot. Its on a ground mount so no problem for me to swap out in a minute.

Putting them in a difficult place to get to, is a personal choice. I like your idea of fitting them in the loft, but if you do, I would mount them on a fireproof surface.

Example with a couple of my TIGO's (they are the old style) mounted on a fireproof board. Don't try and work out the wiring from that picture as it was wired up temporarily as wacky experiment to boil a kettle direct from a solar panel. Folk from St Elsewhere may remember it.

[Mr Gus]

Like the hardie-backer off cut
Are you using these solar panels to cover a narrow alleyway or something?
(We've had panel sealing discussions, so am wondering how you have the edges stuck together for waterproofing)
..if you can hear taking more pictures for us!

Cheers
Gus

[nowty]

Like the hardie-backer off cut
Are you using these solar panels to cover a narrow alleyway or something?
(We've had panel sealing discussions, so am wondering how you have the edges stuck together for waterproofing)
..if you can hear taking more pictures for us!

Cheers
Gus

No,
As we know ground mounts need planning permission , so I built a potting shed partly out of solar panels (3 x 44V). Buildings, including outbuildings don't require planning permission for solar panels on them.



Then I added a cat house extension (2 x 60V panels).



If you don't believe it's a cat house, here is the pussy sleeping in it.



There is also 4 panels (4 x 31V) on the lower front of the house.



Going back to the TIGO's,
The potting shed string is in parallel to the front of the house string. Both strings are similar operating voltage, so they work in parallel even without TIGO's. That parallel string is then in series with the cat house extension string. As the cat house extension string uses TIGO's, the cat house extension adds voltage to the string but keeps the same current of the parallel string up to the current limiter on the TIGO's which I think is 12 Amps.

The potting shed gets high output early morning as it faces steep angle SSE,
The lower front of the house faces SW so maxes out in the afternoon,
The cat extension is very flat angle so maxes out near middle of the day but also outperforms in cloudy conditions due to the flat angle,
So this total string using the TIGOs gives a very flat output all day long from early to late.

[Stinsy]

"potting shed"

I love the way you have actually put some pots underneath to emphasise the point.

I have imagined a huge ground-mount array with chicken-wire enclosing the support structure. Does a chicken coop need to actually have chiskens for it to be a chicken coop?

[ChrisJEvans]

Thanks for all the replies guys.

If I were you I’d do 6x south-facing panels on one string. And have the other string with 6x south and 3x east facing with Tigos on all 9.

What are the advantages of doing this instead of:
3x south facing and 3x east facing with Tigos on all 6 and the other string with 9x south?
I don't mind paying the extra £150 for three more Tigos if I can see a benefit.

[AE-NMidlands]

"potting shed"
I have imagined a huge ground-mount array with chicken-wire enclosing the support structure. Does a chicken coop need to actually have chickens for it to be a chicken coop?

you have obviously got to get the house ready before you look round for birds that you like at a price which is acceptable...
Otherwise a fox will have them instead of you! (Been there, done that. The ark on the lawn wasn't secure enough... and just to add insult to injury the b*gger buried a couple in the flower beds for later, too!)