I am a new PV householder - advice please. Unbalanced strings and wrong inverter

[provr6]

I just had a chat with one of the inspectors from Building Control. He didn't seem too concerned about the risk of water ingress from the brackets lifting the tiles, or brackets or untied cables. Certainly didn't think a visit was necessary, though also suggested that if the installer is in a "compentent persons scheme" they could self certify for structure and weather proofing, and he had no jurisdiction. No idea whether my installer is in such a scheme, though they are quite a large firm, so maybe they are.

I think I am on the verge of giving up the fight and getting on with my life...

I know how you feel. TBH all you've got to do now that's important is get your fit application acknowledgement - then you can get forget about it and get on with your life and wait for the cheques to come in :25:

 

[Robinwood]

cbw, i think we should go for another company!!

 

[juniperz]

Internal Shots, Startup Voltage, todays peak output.
https://picasaweb.google.com/106757...719SolarInternal?authkey=Gv1sRgCKaD3c-WrL6eDw#
So should I fiddle with the startup voltage for string 1?? I.E reduce to 185V from the 199V it is set to.

 

[babba]

Internal Shots, Startup Voltage, todays peak output.
https://picasaweb.google.com/106757129624294668901/20120719SolarInternal#
So should I fiddle with the startup voltage for string 1?? I.e reduce to 185V.

Do you want an answer to this or should I stay in my can ?

 

[MickF]

I got a "sorry that page not found" on the link..

 

[juniperz]

I got a "sorry that page not found" on the link..

Whoops - I forgot to make the page public - should work now:
https://picasaweb.google.com/106757...719SolarInternal?authkey=Gv1sRgCKaD3c-WrL6eDw#

 

[juniperz]

Do you want an answer to this or should I stay in my can ?

Oh, go for it...

 

[SibertSolar]

I find it interesting that this whole business about "reducing the start-up voltage" is seen as a positive function. Out of curiosity, what are people's opinions on how this is achieved, the impact of doing it, and any consequences/trade-off by doing so? The old chestnut that always springs to my mind is "you get nowt for nowt in this world".....

I also find it interesting that some inverter manufacturers talk about "low voltage start-up" but they don't talk about "low power start-up".....

 

[Noshocks]

I was at a power one training day recently, they dont advise reducing the startup voltage as it has been set to achieve optimal output from the MPPT, not to say it wont still work, just not as efficiently. It must be said that any installer that new there stuff would have sorted this at design stage, reducing voltages to inputs is not going to achieve the kwh's estimated in my opinion.

 

[Earthstore]

My opinion here, for what it is worth, some are being harsh on the OP, and some of the information he has been given is not correct.
I am sure that some posters mean well, but do you not think that it would be fair to let the installers complete the install and get it registered, from what I have seen in the photos, although not perfect it is a reasonable install.
Do not start messing with the inverter, if it is not booting up (which it appears to be) then get the installer to "fiddle" with it.

I have posted before about building regs, the installer does not instruct them to visit, some installers can issue a certificate, and some can not, but you do not need building regs, just structural calculations, wind loading, and a part P certificate, and the lack of structural calculations may only cause a problem if you decide to sell the property.
Should you choose to get building regs, in my area the cost is £112, so it may be worth it for piece of mind, but it is not mandatory.

 

[jason121]

i always thought POWERONE boasted a low start up of 130volts

 

[wstevew]

There's not much point lowering the start up voltage too low because you will just wear out the inverter producing next to nothing, or the inverter consuming as much as it generates.

It is probably best the installer adjust the start up voltage of the six panel string so that it does start and ideally at the same time as the larger string does at the higher start up voltage.

 

[babba]

I have seen in the photos, although not perfect it is a install.
Do not start messing with the inverter, if it is not booting up (which it appears to be) then get the installer to "fiddle" with it.

I have posted before about building regs, the installer does not instruct them to visit, some installers can issue a certificate, and some can not, but you do not need building regs, just structural calculations, wind loading, and a part P certificate, and the lack of structural calculations may only cause a problem if you decide to sell the property.
Should you choose to get building regs, in my area the cost is £112, so it may be worth it for piece of mind, but it is not mandatory.

Agree 99% with earthstore and dont go messing as noshocks said its not your job and should have been picked up on design and Im not being mean just honest the installers are ( )

Plus if you go messing you have no come back...when ... if ... the inverter goes pop. 14v is NOT an issue.

GOOD LUCK

 

[babba]

i always thought POWERONE boasted a low start up of 130volts

120v to 200v

 

[juniperz]

Thanks for the recent comments - I have been too busy enjoying the sun to go near the forum
I will not be touching the startup voltage.

I did get myself a cheap 2nd hand Samsung netbook on eBay and I have got the monitoring working via the USB port on the right hand side. Pretty straight-forward with the drivers and Aurora Communicator software from Power One and the integration servce from PVOutput. I can drive the netbook in the attic using LogMeIn remotely, or with UVNC if I am at home, without needing to go up there.
juniperzPV 3.920kW | Live Output
I can even see the data on my Android phone.

And I have spoken to Good Energy and our application for FIT was all in order.

One question - the peak inverter temperature today was 70degC - that seems high (though what do I know?) - is that normal?

 

[sedgy34]

Is it in the loft?

 

[juniperz]

Is it in the loft?

Yes it is.

 

[juniperz]

juniperzPV 3.920kW | Live Output
One question - the peak inverter temperature today was 70degC - that seems high (though what do I know?) - is that normal?

Anyone? It hit 75 today!

 

[babba]

Anyone? It hit 75 today!

You should have got a chinese inverter, they taste better when cooked.

 

[Gavin A]

it'd certainly benefit from any additional ventilation you could put in to the loft, as well as moving lower in the loft space if possible.

those are the internal temperatures within the inverter, and I'm not entirely sure at what point it starts limiting the output, but those do seem a bit excessive to more, and will almost certainly reduce the lifespan of the inverter.

 

[juniperz]

it'd certainly benefit from any additional ventilation you could put in to the loft, as well as moving lower in the loft space if possible.

those are the internal temperatures within the inverter, and I'm not entirely sure at what point it starts limiting the output, but those do seem a bit excessive to more, and will almost certainly reduce the lifespan of the inverter.

Thanks. I dropped a line to [email protected] earlier, so will see what they say.
I looked at few UK installations with the same inverter (on PVOutput.org) that had also generated about 25kWh today, and a couple were down at about 25 degrees C.
I am not at home again until Thursday, but maybe I should think about a fan in the attic...

 

[sedgy34]

You wil get to hot in loft waving a paper fan about lol



I recall in a very early post not to have it in the loft now your concerned

 

[Worcester]

Lofts normally get cooler when PV is fitted (the PV takes the heat not the tiles) It does depend upon how well ventilated it is / isn't.

 

[juniperz]

Power One tech support came back to me and said that 90 degrees C was acceptable, but that ambient termperature in the environment should not exceed 55 degrees C. The internal hit 78.2 degrees C today...

 

[Worcester]

@juniperz, Just looked at your pvoutput logs for the last few days - what's happeing at 3:05pm ?

Looks a nice curve, thoigh I wondered, does something create a shadow across the panels (roof onto garage? )or is is their a tree or telegraph pole?

Or is that when the inverter's at its hottest?

 

[juniperz]

@juniperz, Just looked at your pvoutput logs for the last few days - what's happeing at 3:05pm ?

Looks a nice curve, thoigh I wondered, does something create a shadow across the panels (roof onto garage? )or is is their a tree or telegraph pole?

Or is that when the inverter's at its hottest?

You have a point - strange. I don't think it is when the inverter is at its hottest (that seems to be an hour earlier) but it interesting that the Temperature takes a dip at the same time.
There is not tree or pole, but the scaffolding is still up, so the top lift does cast a shadow on the garage - though I think that is a bit later in the day. And that 3:05 dip is always back on the normal curve by 3:15...

Scaffolding still up because I have them coming back to take a look at the tiles.

I got my wife to check the temperature in the attic - 42 degrees C at 4:20pm. I would like to know what it is at 2pm, when the inverter is at peak temp.

I am a bit disappointed that after the peak of 3608W on 19th July, I haven't got above 3339W since, in spite of gorgeous weather.

While I am rambling, anyone sending data to PVOutput.org using Aurora Monitor on a Raspberry Pi??

 

[Gary K]

Also your FIT tariff is fantastic- just over 49p per Kw

 

[Worcester]

While I am rambling, anyone sending data to PVOutput.org using Aurora Monitor on a Raspberry Pi??

We'll we've got a couple of PI's here and that is one of the things we're going to be working on psot 1st August - do you kinow anyone whose done it yet?

I'd love to chat with them on the PI forums.

(RaspberryGeek is my son on the Raspberry Forums and I use his handle sometimes)

 

[juniperz]

We'll we've got a couple of PI's here and that is one of the things we're going to be working on psot 1st August - do you kinow anyone whose done it yet?

I'd love to chat with them on the PI forums.

(RaspberryGeek is my son on the Raspberry Forums and I use his handle sometimes)

I guessed that was you - hence why I asked ;-)
I quickly decided that I was sad / geeky enough to want to do monitoring and found PVOutput, but I just don't have the time at the moment to figure out linux, even though I could see that the RPi would be the perfect low cost / low power solution for this. I took the easy way out and got an XP Samsung netbook for £50 on eBay. Simple to set up, not much more expensive than an RPi + wifi adapter, but higher power consumption. The Pi obviously doesn't have a screen, but the beauty of controlling it remotely, is that it doesn't matter. My netbook was cheap because I bought it knowing it had a dodgy screen.

I might order a Pi because I like a challenge when I have more time, and they are ridiculously cheap (£22). The problem seems to be testing - if I disconnect the netbook on a sunny day and the Pi doesn't work first time - which it won't for a variety of reasons, like USB drivers to start with - then I have lost a chunk of data that the netbook would have been collecting. And if I do this after dark, the inverter won't be producing any data to test!

I don't know anyone that has done it - the only reference I found to 'Aurora' on the RPi forums, was about controlling cylinder thermostats. If you get anywhere with this after 1st Aug, please let me know (though probably off forum as I think I have gone a bit off topic!).
I did find a useful thread about wireless drivers.

 

[Gavin A]

what's this rasberry stuff about then?

I too want to look at stuff like this in August, as it seems there's been a fair few new products come along recently.

 

[juniperz]

what's this rasberry stuff about then?

I too want to look at stuff like this in August, as it seems there's been a fair few new products come along recently.

It is a very cheap computer with an ARM processor so it will not run Windows (well maybe a flavour of Windows 8) and runs linux, possibly Android.
"The Raspberry Pi model B board is supplied as the circuit board only, and comes without operating system, SD card, power supply, keyboard, case or cables. "
I think it could be used for monitoring an inverter like my Power One by adding a USB cable, a USB wifi adapter, an SD card with an operating system on it and a power supply (same as an android phone - micro USB plug). And a USB keyboard to set it up. And maybe a lego case! Then just leave it to consume something like 2 watts.

 

[Worcester]

Raspberry Pi | An ARM GNU/Linux box for $25. Take a byte! - A whole new can of worms - a linux computer for £25 ! (that's UK inc shipping)

Geeksville :1eye:

 

[Gavin A]

hmm luckily, one of my team is even geekier than me, and has a sideline in taking old laptops apart and making them work again, so this could be on.

 

[wstevew]

I have a Raspberry Pi. Not done much yet apart from boot up XBMC (Media Centre). I dont think it will become a useful android device as current android devices now have approx 4 x the memory of the Pi and at least 2x the processing power. More than enough power to monitor an inverter and upload to the web and some more.

For android the MK802. about twice the price of the Pi though.

http://www.engadget.com/2012/06/07/mk802-android-4-0-mini-pc-hands-on-impressions/

 

[Worcester]

I nearly hijacked this to talk about PI's so I've started a new thread instead!

p.s. I respect and understand the work you've done on your Android monitoring system for the SMA inverters.

 

[juniperz]

You have a point - strange. I don't think it is when the inverter is at its hottest (that seems to be an hour earlier) but it interesting that the Temperature takes a dip at the same time.
There is not tree or pole, but the scaffolding is still up, so the top lift does cast a shadow on the garage - though I think that is a bit later in the day. And that 3:05 dip is always back on the normal curve by 3:15...

Scaffolding still up because I have them coming back to take a look at the tiles.

I got my wife to check the temperature in the attic - 42 degrees C at 4:20pm. I would like to know what it is at 2pm, when the inverter is at peak temp.

I am a bit disappointed that after the peak of 3608W on 19th July, I haven't got above 3339W since, in spite of gorgeous weather.

While I am rambling, anyone sending data to PVOutput.org using Aurora Monitor on a Raspberry Pi??

Replying to myself. I think the inverter is limiting itself when the internal temp is above 70 - and it has been as high as 78, so I am generating less than that peak of 3608W before I was connected to PVOutput. I will try an electric fan when I finally get home tonight. (The irony of a powered fan and laptop to get electricity. And of generating less when the weather is the best of the year).
I have ordered a Raspberry Pi to play with though - 18 weeks lead time at RS and 5 weeks at Farnell - they are popular little things...

 

[sedgy34]

Replying to yourself
I think your thread is coming to an end

 

[Somecamel]

Re: Take advice n solar Panel Installation problems

Shameless Plug

 

[SolarCity]

Yep, and he's gone now. In just 1 hour he has made 5 posts - in one he praised the training course he had taken, in another he was bigging up HIS company Solawise and then in another he was praising the company that fitted the panels on his home - Solawise.

All of this in the kind of grammar that would make Jeremy Kyle raise a plastic eyebrow.

 

[Ecohouse]

This all sounds very wrong to me, I am a system designer. sound to me like you have 3 possible solutions. If the system is split my suggestion would be one central inverter for the main array and 2 Soladin slave inverters for the additional 4 panels or a Solar Edge inverter with individual power optimizers or micro inverters.

The twin tracker will be sufficient for spliit arrays but the loads are to unbalanced in this configuration.
Hope that helps

 

[Dan]

Don't mind me while I bump some threads in the solar PV forum. If they're not current or applicable topics, just ignore the threads; they'll drop off the page. If they are, feel free to chip in and chat solar stuff in the solar panels forum.