@transparent thanks - sounds like generally its working correctly. I think the main thing I now need to see is how much we produce with direct sun.

It remains puzzling why last year production was around 40% less than previous years even though it seemed to me above average sunshine in main months.

I depends somewhat on where you live @tim441 but most of the UK will have sunshine this next weekend.
That gives you just enough time to have an AC/DC clamp meter delivered.

Posted by: @tim441

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It remains puzzling why last year production was around 40% less than previous years

Two possibilities:

• system degradation, although 40% drop is unusual
• an overall cloud of gloom and despondency covering the UK during the energy crisis 🙄 

@transparent ah yes, your final thought seems very likely to be the case. Amazed in that case we produced anything at all!!

on the subject of clamps... it seems the clamp part is AC only in the one you linked? I have found a similar one (that is virtually unused since purchase!). But that's also AC clamp only

Is there any benefit in checking the AC via clamp? in case the meter has gone faulty (unlikely?).

For the DC side I guess i could check the production using the test leads? or find another test meter that can test DC via clamp/jaws....

Posted by: @tim441

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it seems the clamp part is AC only in the one you linked?

Apologies; I'd followed the CPC menu system to find that item, but forgot to check that it had indeed arrived at a suitable clamp meter.

The equivalent one, which does indeed allow measurement of both AC and DC current is this one at £48.

The one I use is made by Aneng, and bought directly from the manufacturer in China using AliExpress for about £23:50 incl carr & VAT:

@transparent no apologies necessary - I very much appreciate the help and guidance. Its all a learning curve for me!

That Aneng ST209 is also now available on ebay for about £26-£28, and supplied from UK stock. 🙂 

I'm still trying to get into the habit of using my clamp meter.

I made a mistake a couple of weeks ago and placed my 'ordinary' multimeter in circuit.
It was correctly connected to the 10A DC Amps range, but I'd forgotten to allow for the inrush-current on the DC-DC converter which was to be switched into circuit.

Here's the result:

Yes, the 10A fuse blew. You can see the glass cracked beneath the circuit board.

However, the fuse only succeeded in breaking the circuit after three tracks on the board had been vapourised.

Posted by: @transparent

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Those figures for a (light) cloudy day sound about right to me.
I generally assume that such conditions will decrease panel output to around one-seventh of that obtained under full sun.

Not having monitoring equipment is an issue which regularly crops up on this Forum.
It applies to almost every type of technology being installed by 'professionals'. 😒 

Not only does it make life difficult for those, like you, who are now trying to report whether you may (or may not) have a problem
... but it also reduces the knowledge-pool on energy matters within the wider population.

It seems odd to me that MCS fail to make adequate monitoring a mandatory part of installations by their accredited members.

There is a simple answer, monitoring costs money, and has to be installed and commissioned by someone who knows what they are doing, which I feel may be almost impossible. 🙄 

Posted by: @transparent

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Here's the result:

Yes, the 10A fuse blew. You can see the glass cracked beneath the circuit board.

However, the fuse only succeeded in breaking the circuit after three tracks on the board had been vapourised.

ouch! 😱 🤬 😬  

Posted by: @tim441

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@derek-m I am pretty sure it is with optimisers on all panels. However its not entirely clear from paperwork. 

There is a small amount of early morning shade from a chimney to East and significant shade from (say) mid-afternoon from neighbour trees to west. So I'm pretty sure optimisers were required.

For the number of strings would we be able to tell from the number of DC cables entering inverter? There are 2.

 

If you have two cables it could mean that you have two strings. The reason I asked is that your annual output is approximately 60% of expected, which could equate to energy being received from four panels in full sunlight, whilst the energy from the three sunny panels plus one shaded panel has been lost. How technical are you?

Posted by: @derek-m

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If you have two cables it could mean that you have two strings.

For that size of array, I strongly suspect that each 'cable' is in fact a single 4mm^2 wire.

Two wires equals one string.

@derek-m understood... I guess its possible .... but lets see the output on a sunny day as that should help as well. 

I'm not an electrician! But have a moderate understanding I would say through experience etc. Did you have a specific thought on a further test?

@transparent @derek-m in case it helps... here is pic