Any suggestions for Inverter woes?

[balbecdaze]

If you really can't resist it, feel free to post replies of the "well what did you expect?" variety. However constructive comments will be appreciated!

Last July I installed at home an Eversolar TL4000GB, connected to 2x8 Suntellite ZDNY250C60 modules. The inverter is sited outdoors, facing south (160[SUP]0[/SUP]). I did put a roof over it in April, and added a £3 solar fan from ebay last month!


Picture taken 9am today, inverter is in full shade from ~11am.

Both DC and AC cabling are 6mm[SUP]2[/SUP], AC volt drop 1%, DC Volt drop .5% or thereabouts. Grid voltage is 242V pretty much whenever I measure it, there only seems to be 1 other ~2kW installation on our substation as far as I can see anyway. Insulation Resistance >999MOhms AC and DC. Continuity good.

Now I first noticed this problem ~2 months ago I guess and its getting steadily worse. Whenever there is anything like direct sunlight, and anything like heat (18[SUP]0[/SUP]) the inverter says Reconnecting to Grid and cycles through a countdown. It won't reconnect again until hours later now. In fact its just done this (10.30am). There is no error message. When I first noticed this, if I turned off half the panels, it would function fine but now even with just eight panels it cycles in Reconnect mode.

I've tried contacting eversolar via email and their service section of their website but no replies as yet.

Any suggestion as to what my problem is, what I should test/check, how I can solve it?

I'm not a very experienced installer (3.5 installs) and so other than the obvious I'm at a bit of a loss.

 

[whinmoor]

Did it come with a 5 year warranty? It might be time to discuss the matter with your supplier. They should have some technical support. It might be a good opportunity to practise your Mandarin!

 

[balbecdaze]

Yeah, came with warranty. A call to the supplier can't do any harm.

As for mandarin - :sick:!

 

[whinmoor]

Last time we installed an Eversolar, we had to register a warranty card by email. Did you do this?

 

[Worcester]

Remember though that SMA recently bought a majority stake in EverSolar, so they will want to preserve / improve its reputation.

 

[balbecdaze]

SMA thing hopeful, yes. I could always try contacting them I guess.

Whinmoor, I think I did, but I can't find any record of doing it (so much for my QMS!). I have registered it on the service part of their website (about 1 month ago).

And on the plus side, I still have the original box and 1/2 the packaging! The box keeps (some of) my kid's toys neat-ish, and the foam insert is her version of Iggle-Piggle's boat!

 

[balbecdaze]

Update after calling supplier:

They suggested checking the Voltage drop by locking the display onto Vac so I could check whether it was trying to push too many volts through, luckily the sun came out and for the minute or so before it tried to reconnect again, with the power between 3.6 and 3.9kW, the Vac was around 244V. So not a voltage drop issue.

That's odd though isn't it? I'd noticed once before that the Power reading actually went over 4kW.

Taking my measured reading of 242V (supply), 242Vx16A=3872W.
Using the nominal value of 230, we get the 3.68kW.

I'm going to pop my clamp meter around an AC line and see if I can get a measurement while the sun's out and before it tries to reconnect to see if its outputting more than 16A at any point.

There's nothing for the installer to alter with this inverter, its factory set.

 

[SolarCity]

I wouldn't worry about the >16A thing - that won't affect the running of the system.

This sounds like a high voltage thing despite the readings you are getting. Have you noticed the Vac while the inverter is actually grid connecting and producing?

 

[balbecdaze]

The Vac from the inverter display (i.e. not measured by me) was around 244V for a minute or two today while the Pac display was around 3.7kW. Then it shut down of course. The value in the manual for Grid Voltage range is 207-264V.

I will next be at home during the day on thursday so I could take a reading from a socket at the same time, if the sun is out.

 

[jason121]

I had s similar problem with the Steca inverter, after a few visits checking voltages they decided to replace the inverter, software issue.

 

[balbecdaze]

Right, nice sunny day, should manage to verify/eliminate voltage drop issues. The inverter did just fail again, it was outputting 2.9kW @ 246V (from display). I got a voltage off a socket of 244V (nearest socket to DB) before it failed. With no power from inverter, Voltage at that socket reads 242V.

Had hoped to turn it off for 10 mins and then turn it on and take a Voltage reading at the Garage unit at the CU end to double check this but it's not playing ball.

Any cast iron ways to check the voltage drop without a functioning inverter?

 

[SolarCity]

You want to be testing the voltage at the AC isolator next to the inverter rather than at the DB although this isn't looking like the likely issue unless your inverter is set at the incorrect country settings. Are on G83 settings?

 

[balbecdaze]

Thanks for the reply, I would have liked to take a reading at the inverter but I didn't want to break the isolator housing, is there a simply way to override the openable-only-when-off safety feature of the AC isolator, if you see what I mean? Its a salzer one.

 

[SolarCity]

I'm not familiar with that brand but you normally can override it.

If not, just hard wire it for the sake of your test.

Did you check the country settings?

 

[balbecdaze]

Well other than it being the GB version, with Grid Standard G83/1 on a sticker on the side, there's nothing to check. There's nothing you can alter via the display buttons. It comes as is.

 

[Worcester]

Thanks for the reply, I would have liked to take a reading at the inverter but I didn't want to break the isolator housing, is there a simply way to override the openable-only-when-off safety feature of the AC isolator, if you see what I mean? Its a salzer one.

Nope you only want to open it when it's off , that's the idea of the isolator. I would strongly advise you get an expert in to check it for you.

 

[balbecdaze]

Er, I have all the relevant qualifications, accreditations and competencies Worcester. Just not the experience of a wealth of installations like some of you guys. I really appreciate any time spent to help.

 

[whinmoor]

We've never installed one of these outdoors but I know they are IP65 rated. Siting it in direct sunshine is probably not a smart move so could you relocate it or extend the overhang on the cover?

Have you considered replacing this unit with another brand for a few days? If the other brand struggles/fails, you'll know it's not the Eversolar unit at fault and the problem lies elsewhere.

Did you install it in damp conditions? Could it be that there's some moisture in the internals?

How far away are the panels from the inverter?

 

[Worcester]

@balbecdaze, sorry didn't mean to 'dis' you, this is straightfoward trouble shooting.
1) Check actual voltages at inverter - that's where the high voltages are - the drop happens between the inverter and the incoming.
2) No different than testing a CU, - you have exposed conductors then.
3) On most inverters, you can test the voltage (and fire them up) even with the cover off, sorry can't comment specifically on the EverSolar ones.
4) If you can't, then why not temporarily wire in an IP65 rated outdoor socket to the isolator.

5) Most important - check the country settings on the Inverter - it is set to G83/1-1 isn't it?
- Looking at the spec sheet it appears this isn't configurable and despite being set to 264V @ 1.5 secs, the actual trip values in the test were 259.4 even so, that's pretty high.
6) See if the inverter can display the frequency, if it's not overvoltage it may be that. (Very unusual but it may be)

If all else looks OK, I guess some of the components must have failed, so you should get a swap out unit.

 

[balbecdaze]

@ whinmoor, no dampness, installed during a lovely hot weekend, end of july last year. Could there be dampness in the inverter anyway? I guess of course, just from condensation whenever the box is colder than the internals.

Panels are 25m from inverter (well, 25m 6mm SWA plus a metre of the 4mm solar cable the panels themselves use).

Direct sunshine - that is, I think, what I've learnt from this install (at least its at my own house!). I could extend the overhang (have done once already) but to be honest, I think the damage is done. It wouldn't even start today once it was overcast after it had had a bit of sunshine.

I would love to replace the unit with another for a few days (This springs to mind). There is no cash though!

 

[whinmoor]

You could take your inverter to someone else's house with a 4kWp system for a few hours for test purposes?

 

[balbecdaze]

@Worcester, no worries.

1) Yes I'd like to, but I didn't want to actually damage the Isolator housing by trying to twist the switch with the cover off, I was just asking SolarCity for advice on how to do this. I will try your suggestion 4 next time I'm at home during sun!

2) Yeah, I'm very cautious (scared) about working live but it does need to be done sometimes - especially with PV, this is my first PV fault-find so I'm just trying to be extra cautious, hence your excellent suggestion 4.

3) Don't think I can do this with my inverter, I'll wait for a come back from my supplier before I have a go. The possibility was vaguely raised of a replacement after my last phone call, I'll wait and see.

4) I'll do this.

5) Thanks for taking the time to check this out, that's why I wanted to check the voltage at the AC isolator because the inverter display is well under that when it cuts out.

6) The inverter does display the frequency @ 50Hz, backed up by my Megger from a socket.

I concur with your conclusion, but I need to check the voltage at the inverter with my meter rather than relying on the inverter display in order to definitively rule out a voltage drop issue.

Thanks again for taking the time.

 

[balbecdaze]

Nice idea Whinmoor. Bit of a long shot this but any of the viewers of this thread have a 4kW system near Bristol they wouldn't mind me taking temporarily out of commission? Have to be during a sunny day too.

Perhaps I'll be brave and call one of the local big boys to ask for a loan.

 

[balbecdaze]

Re: Any suggestions for Inverter woes? Minor update

Resurrecting this thread as I've finally managed to be at home on a day when:

a) there's enough cloud cover, lowish temperature for the inverter to run normally for a few hours.
b) I can predict(ish) when the sun is about to burn through the clouds enough for it to make my inverter cut out.

And, standing over the AC isolator with my meter, measuring the output voltage and it cuts out at 242V, Power output at that time was approx 2.6kW, frequency 50.0Hz for what it's worth. This confirms earlier readings from the inverter itself of happily within range voltage outputs when it cuts out.

Any other ideas and do I have to deal with the manufacturer or should my supplier take care of it if it is a warranty issue?

 

[Worcester]

As has been previously suggested, are you absolutely sure it's been set up for G83? (220V+10% = 242)
Ignore the stickers They can easily be wrong.
If the manual doesn't help, call your distributor and then the supplier to see if you can check in any way.

 

[balbecdaze]

As sure as I can be Worcester.

It's definitely output at 246V before, and it was fine on sunny days in winter. Really seems to be a combination of heat and light that does it. Been very frustrating these last few weeks ...

Take now for instance, irradiance at panels ~260W/m2, temp by inverter 26C, inverter in full shade because the sun's "gone round the corner", inverter (including heat sink) cool to touch ... nothing. I'd expect something at 6pm on a nice summers evening, <1kW, hardly pushing the specs of the inverter. The panels are in sunlight. And I'd turned off the AC and DC, waited 10 minutes then re-energised, just for fun.

I did call the supplier again today, got put on hold then promised a callback. Much like my inverter, nothing happened.

 

[Gavin A]

As sure as I can be Worcester.

It's definitely output at 246V before, and it was fine on sunny days in winter. Really seems to be a combination of heat and light that does it. Been very frustrating these last few weeks ...

Take now for instance, irradiance at panels ~260W/m2, temp by inverter 26C, inverter in full shade because the sun's "gone round the corner", inverter (including heat sink) cool to touch ... nothing. I'd expect something at 6pm on a nice summers evening, <1kW, hardly pushing the specs of the inverter. The panels are in sunlight. And I'd turned off the AC and DC, waited 10 minutes then re-energised, just for fun.

I did call the supplier again today, got put on hold then promised a callback. Much like my inverter, nothing happened.

IME all inverters we've used actually display 'G83' on screen at some point in the start up procedure for the inverter, so I'd really advise to switch the inverter off and on, then watch closely to ensure that it does actually display this in the start up procedure.

If not, then I'd say there's a good chance it's been set up wrong despite the sticker.

Another possibility if that the nominal grid voltage has been set wrong at 220V, which the inverter would use as a reference to set the maximum sustained voltage at +10% of that level.

For my money, those are the 2 most likely scenarios here, can't think of anything else it'd be to be honest.

 

[Gavin A]

eta - ah, other than the inverter being outside in full sunlight and overheating as a result. They shouldn't be put in full sunlight.

 

[balbecdaze]

eta - ah, other than the inverter being outside in full sunlight and overheating as a result. They shouldn't be put in full sunlight.

That, for my money, is what did it. It didn't specifically say G83 on startup, although it did say TL4000 GB, the GB standing for UK setup. As I say, its happily output at more than 242V on colder days.

So, after calling the supplier again yesterday, what arrives today?

A shiny new updated inverter.

Of course, that's probably the last of the sun for the year as well. :smiley2:

I've extended the overhang of the shade and installed it a little higher than the other one, its also wider and shorter than the old model, so that would help too. I'll keep an eye on the shading, I think I'm good at least apr-sept with the current setup.

Many thanks for all the helpful replies.

Its kinda kudos to the supplier, but then again they left me with the suggestion that they'd get in touch to arrange a replacement one month ago, so I've learnt the power of a bit of pestering too.