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!