South Wales (Cardiff) solar installer recommendations please.

[deeyup]

Hi, not been here for a long time as have not needed to.

anyway, I've a problem with my solar plant.
13xsanyo 235 hit from what I remember?
power one pvi 3.0 outd inverter (maybe a 3.6?)
All fitted December 2011.


at startup after wet weather I'm getting low riso error, sometimes as low as less than 1MOhm. The inverter will refuse to connect anywhere less than 1.5MOhm.

talking to ABB they say it's water in the dc side, either, unlikely a faulty panel or most likely cables or connector.

Can one please suggest a good solar Pv company who could maybe diagnose and fix this please?

thanks,

D

 

[Gavin A]

is it only wet and cold weather?

If so, nothing to worry about IMO, the inverter can be reset to 0.5MOhms. We particularly see this with panasonics, I think it's related to their increased capacitance due to having thin film and mono-crystaline cells. The clue being that it only happens in cold wet conditions, not in warm wet conditions - if it were just from water getting in to an MC4 then it'd happen in both.

 

[whinmoor]

if it were just from water getting in to an MC4 then it'd happen in both.

Would these 2011 panels have MC3 connectors rather than MC4? If so, there may have been either used adaptors or cut off and replaced some connectors. That introduces more scope for error.

 

[Gavin A]

Would these 2011 panels have MC3 connectors rather than MC4? If so, there may have been either used adaptors or cut off and replaced some connectors. That introduces more scope for error.

it does, but the above still applies, if it only happens in cold weather than it's not water getting in to connectors.

We've seen this issue so many times every winter, and panasonic / sanyo HIT are by far the worst for it. 1 Mohm is still a huge resistance to earth, it equates to around 0.3mA of earth leakage current, so the inverters are tripping out at 1% of the safe limit for standard domestic 30mA RCD.

 

[gnselectricals]

I had similar on 2 jobs last month which I had to check out for a company I sub to who installed them 4 years ago. All running fine until wet and cold as you say then taking out a 100ma on one job and a 30ma on the other. No problems when I tested so I assume it's the same 'fault'

 

[Gavin A]

I had similar on 2 jobs last month which I had to check out for a company I sub to who installed them 4 years ago. All running fine until wet and cold as you say then taking out a 100ma on one job and a 30ma on the other. No problems when I tested so I assume it's the same 'fault'

a fault that's tripping out the rcd is very different to one that's tripping out the RCMU on the inverter, as the RCMU is set to trip at 1% of the leakage current of the RCD.

 

[deeyup]

Thanks for your replies, much appreciated!

i only noticed the "problem" in early February after a particularly low fit cheque. The rain was relentless throughout the winter though so may just be that?
anyhow, I observed the inverter trying to start up.

http://youtu.be/XRip1bCdhHc

if it had been raining overnight, no startup.
it may startup later in the day as it does measure riso repeatedly if too low.

Never thought to take note of temps, but most probably less than 6°c most mornings I would think?

I will get into settings and lower the threshold of the riso and see how it goes.

other than that, when the sun is out, the system is working great. I'm happy to see after nigh on 5 years the inverter reports peaks of over 3200watts, within 2 watts of when the panels were 1st put up. Zero degradation it seems?

The plant is under warranty, but the installer no longer does solar, so has zero interest in helping saying that it's storm damage and to call my insurance. :uhoh2:

Again, thanks for taking the time to reply here, it helps immensely.

 

[f0ster]

I have had this on installations a few times that I have been asked to attend. it is usually one of the MC4 connectors that has not been located up out of the way,