MCS Array test help

[Dan the man]

I have my MCS assesment booked in 3 days and I need some help with the testing on the DC side, We did not perform the tests and I need some rough figures for Voc and Isc string test and also the [FONT=&quot]Array insulation Resistance Pos- Earth and Neg-Earth.
Any help would be much [/FONT]appreciated
Thanks Dan

 

[Dan the man]

Its a 1.08Kw array with sb1200 inverter

 

[Martin Dawes]

Why not test it now? The tests will take you minutes and they'll be accurate. I can explain how to do the test if you're unsure.

 

[seansparx]

is it possible to send a copy of MCS test array help

 

[oslosolar]

If you don't test it you will fail make sure there is enough sunlight over 400 at least

 

[powervan]

Hi just spotted your offer pv array test help! mcs next week just completed job but looking at pv array form and havnt got a clue? ie just installed 20 x 195w zn shine panels 2 x strings of 10 with sunny boy 3300 but not sure where to fill in form?

 

[yellowvanman]

What form you got? I can let you have an excel file you can fill in and will walk you through it.

Have you made the measurements for Voc and Isc?

 

[powervan]

hi i have a f43 pv array test form ie starts off with string 1234
presume as have 2 strings i use 1 and 2 quantity 1 =10 2= 10
array parameters voc ? panel spec is 45.21v
isc ? 5.56a
protective device ?type
rating (a)
d.c.rating (v)
capacity (ka)
wiring type
phase (mm2) 4.0
earth( non i presume)
string test method
annex 2 voc ? isc ? sun?

polarity just a tick
inverter serial
ins res test volt pos - earth and neg - earth (but as no earth i presume leave this)
any help appreciated

 

[powervan]

one other thing need to provide schematic for first job ! do u use a certain software ? ie how do i get a schematic sorted without getting me colouring pencils out? (i was never no good at art)

 

[yellowvanman]

PM your email address and we can do this offline.

 

[powervan]

[email protected]

 

[C4RTA]

Hi, I am just reading all of the comments and i have the same problem, i have done my first job but i am still trying to figure out this test sheet. Also, the panels i am using have a voltage of 37.5. i have two strings, one with 7 panels and one with 9. my first string with 7 panels has a total voltage of 262.5 volts but when i test it at the inverter to get my VOC i am getting 248, the second string of 9 panels works out at 337.5 but when im testing it i am getting about 317volts, i would say the DC cable run is 4-5m, it works out to be around 5-7% volt drop. this does not seem right, any ideas? does anyone know the average volt drop? also, i need an irradiance meter, any particular makes i should look out for? thanks for the help!

 

[yellowvanman]

You're readings don't seem to far out. Check the Voc/Isc graph for the modules you are using. The Voc is stated for stc values of 25C and 1000W/m2, but if you look at the graph you will see that the Voc does change slightly with irradiance levels.

To my mind what you've got looks OK, was it a cloudy day. From you Voc measurements I guessing it was!

This meter works for me:

Solar Power Meter - Energy Meter for Solar Energy - Tenmars TM206

 

[powervan]

C4RTA listen to yellow van man!!!! he helped me !! in SIMPLE terms !! not that im a SIMPLETON GOT MCS TODAY!!! thanks again!!

 

[C4RTA]

I forgot to mention that Ive spoke to a guy that works for ELECSA and he says that that volt drop seems too high for being such a short DC run. yes it was cloudy. I have had a look in the manual for the panel i used but it does not have a graph in. only has a table of the Voc, Isc readings for the panel etc. Do you know what the irradiance would be on a cloudy day, rough idea as i do not have a meter yet or is it impossible to tell? cheers!

 

[yellowvanman]

As an example - on a data sheet I have in front of me. Sharp NU-180

Graph is a bit coarse, but @ 1000W/m2 Voc = 30.2V
@400W/m2 Voc is in the region of 28V - thats a 7% difference - which adds up to what you're getting.

Difficult to guess what irradiance you got, would depend on time of day and even where you are!

 

[C4RTA]

sorry but i have a slight memory issue, if there are 2 strings one with 9 panels and one wit 7 on, will the Isc that you measure/calculate be the same on both? or one slightly higher?

 

[yellowvanman]

If the same panels, Isc should be the same no matter how many panels/string

 

[C4RTA]

Thanks, was getting my self confused. Appreciate the help!

 

[PipMeister]

Hi YellowVanMan

I would appreciate help with f43 form for MCS if you would? My number is 07745 304179 or [email protected]. I'll phone you back. It's just a couple of the boxes I don't quite understand.

Cheers Phil