Pv Problems?

[newman]

After a difficult birth I got my solar panels up and running in July, having paid for them in Febuary,

Everything seemed ok

Till today, at 8 oclock this morning after a light frost ,I noticed the frost on 15 of the panels had thawed out ,but no 4 panel was fully frosted, is there any significant to this

 

[ProDave]

Did they forget to connect that one and you have been running one panel short all that time?

 

[newman]

Did they forget to connect that one and you have been running one panel short all that time?

Could be..............is there any way of checking.... besides frost

 

[ProDave]

read off the dc voltage from your inverter, and compare with the data sheet for your panels.

 

[newman]

read off the dc voltage from your inverter, and compare with the data sheet for your panels.

What bit of the data sheet should I be looking at

 

[steptoe]

Vmpp is the figure you are aiming for,

What panels have you got newman?

they should be on your MCS registration sheet.

 

[newman]

Vmpp is the figure you are aiming for,

What panels have you got newman?

they should be on your MCS registration sheet.

Hi, I have got a Solar Photo Voltaic Commissioning Sheet, it says the panels are SunTec STP250S-20/wd

IT allso says

[1string] [2string]

String Test Voc 300v 300v

Isa 1.3A 1.3A

Sun 120w/m2@3degree Same

 

[sammers230]

How many panels are there? If there is an odd number then by the looks of the strings one isn't connected as the string voltages wouldn't be the same. Could do with checking the inverter for its readout of string voltages.

 

[ProDave]

Googling your panels finds the data sheet here http://www.google.co...pNtHl-Qsponk9Lg

From that Vmpp 30.5 V

You say you have 16 panels, I suspect wired as two strings of 8 into the inverter. Can you confirm you get two voltage and current readings on the inverter. If so both should read about the same and in the region of 244V

The fact you have two open circuit voltages on the comissioning sheet sugests two strings and both giving the same 300V open circuit suggests all panels are connected.

 

[steptoe]

Dave, going by the rest of the install it wouldnt be wrong to think that perhaps all the necessary testing wasnt carried out.

 

[kerching]

Is this the same story that 'ran and ran' a while back? Installed by Kermit, Miss Piggy and Gonzo.

Any road up I know as much about Solar PV as I do about Skin Effect Theorey and Quantum Origami but, if one of the panels 'goes moody' would it take itself out of the string, blow a fuse or whatever? or would it take out the complete string...a bit like the old maas tree lights used to do; just curious

 

[steptoe]

Depending on how well set up the internal of the panel is, it will take itself out, but it may also drag the rest of the string down certain amount too.

 

[ProDave]

Dave, going by the rest of the install it wouldnt be wrong to think that perhaps all the necessary testing wasnt carried out.

Yes I hadn't twigged which install this was.In that case those "test results" are probably a work of fiction.

Just have a look at your inverter. It should tell you the DC volts of the panels at any given time. The two strings should give pretty much the same reading. Come back and tell us what readings you have.

By the way, the old thread about the problems you had just seemed to die, without a solution being found. So please do update that thread to tell us how you got it sorted in the end.

 

[kerching]

Ah, so it is the same thread.

I followed this with great interest. Didn't one of our mottley crew pay a visit for a shufti? or has Msr Merlot arrived early ce soir

 

[steptoe]

Ah, so it is the same thread.

I followed this with great interest. Didn't one of our mottley crew pay a visit for a shufti? or has Msr Merlot arrived early ce soir

that woulda been me, :|

it was a dire install, and it wasnt surprising it didnt work properly.

 

[ProDave]

that woulda been me, :|

it was a dire install, and it wasnt surprising it didnt work properly.

So what was done to put it right?

 

[steptoe]

another bodge,

the installer did put a new seperate feed in for the PV,

the problem was a massive VD, not to mention the load of other contraventions in the way the original install was done,

but it was the VD that was stopping the PV from working correctly.

 

[newman]

Yes I hadn't twigged which install this was.

In that case those "test results" are probably a work of fiction.

Just have a look at your inverter. It should tell you the DC volts of the panels at any given time. The two strings should give pretty much the same reading. Come back and tell us what readings you have.

By the way, the old thread about the problems you had just seemed to die, without a solution being found. So please do update that thread to tell us how you got it sorted in the end.

Yes, sorry,should have said

After a lot of going back and to,and alot of help from Steptoe and others,the installer put in a new 25mm 2 core cable in from inverter to house CU,FOC.

He put a copper rod about 10 foot from the inverter and told me that was the earth

He had id the earth at the house as TN-S ,when steptoe came down he said it was TN-C-S

Anyway since the new cable it has been working

I will check the inverter tomorrow,I rung SMA today and they said to disconect the dc cables and measure the votage out put and compare both strings ,needless to say I am NOT going anywhere near the cables

 

[ProDave]

Yes, sorry,should have said

After a lot of going back and to,and alot of help from Steptoe and others,the installer put in a new 25mm 2 core cable in from inverter to house CU,FOC.

He put a copper rod about 10 foot from the inverter and told me that was the earth

He had id the earth at the house as TN-S ,when steptoe came down he said it was TN-C-S

Anyway since the new cable it has been working

I will check the inverter tomorrow,I rung SMA today and they said to disconect the dc cables and measure the votage out put and compare both strings ,needless to say I am NOT going anywhere near the cables

Thanks for the update.You should be able to read the dc voltage from both strings from the inverter. Don't go disconnecting them and measuring them without being competent. 300V DC is a lot more lethal than 230V ac so we don't want you touching that.

 

[steptoe]

Yes, sorry,should have said

After a lot of going back and to,and alot of help from Steptoe and others,the installer put in a new 25mm 2 core cable in from inverter to house CU,FOC.

He put a copper rod about 10 foot from the inverter and told me that was the earth

He had id the earth at the house as TN-S ,when steptoe came down he said it was TN-C-S

Anyway since the new cable it has been working

I will check the inverter tomorrow,I rung SMA today and they said to disconect the dc cables and measure the votage out put and compare both strings ,needless to say I am NOT going anywhere near the cables

for those of you interested the EMT for this rod is less than a metre from a CU with extraneous metal that is supplied by an exported TNCS ray

Newman, Im still trying to make some headway with this, I havent forgot