I'm Concerned About My Voc

[John Preston]

Ok here goes, my first posting!

I am ready to install the following at my little farm in France:

Sunny Boy 1700

Max DC volt : 400

Fuji flexi amorphous panel.

Voc 429v

Vmp 319v

Isc 0.39A

Imp 0.288

So you can my concern that the Voc is greater than the Max DC volt of the Sunny Boy.

Is there any kit to limit the maximum Voc to 400v?

Or am I being a bit too cautious?

I have this awful feeling they are not compatible with each other.

 

[steptoe]

is this the measured Voc ?

 

[John Preston]

This is the figure given on the spec of the panel.

 

[John Preston]

Forum rules will not let me post a link!

FWave solar modules

FPV1092COM4

Fuji electric

I have 12 panels in total.

 

[John Preston]

http://www.telepower.com.tw/pageGetFile.ashx?no=44352&file_name=F-WAVE-92_03.pdf

I'll take a look at the profile, thanks

 

[John Preston]

If I drop some panels how can that make a difference?

Each panel is rated at a Voc of 429v and I was connecting them in parallel anyway.

So is it not possible to protect the possible over voltage with anything? Really didn't want to change the inverter :-(

 

[John Preston]

Ok, thanks for the help so far....

 

[John Preston]

Doh!

Ok cheers for that anyway.

 

[binky]

Amorphous panels have a few issues of their own unique to this type of panel, I would defo contact SMA for advice on a suitable inverter, and ask if there are any specific requirements such as earthing.

forgot to say it's a beeding old inverter model anyway, better off with anything from the TL range - much more efficient.

 

[Barx]

The reason this is suggested is most common types of setups tend to use panels with low voltages (current job i'm on 37.7v) and the panels are connected in series to get the voltage higher. Thus removing a panel would drop the voltage to an acceptable level. Though this does not seem to be the case for your panels, I personally haven't a massive experience level with differing types of panels, but I definably haven't seen those sort of characteristics.

 

[John Preston]

Well I like a challenge so I'm not surprised at the results so far.

I'll call SMA tomorrow and report my findings ; -)

 

[binky]

I've been looking at Amophous panels for years, especially as no one wanted them and they were being flogged off cheap. The technology is superior to standard silicone panels, but generally need  a much larger surface area. On paper they don't look clever, but the Schuco rep was telling me about a 2 demo systems they fitted, with a 50kW East West amorphous panel array outperforming a due South standad panel array by a notable amount. The frameless all glass panels look quite spectacular compared to normal panels.

 

[John Preston]

Found a better spec for these flexible panels of mine.

http://www.mirasol-gmbh.de/sites/mirasol-gmbh.de/files/J-KS300104_English%20specifications%20of%20FPV1092COM4.pdf

Gives a bit more info on them.

Binky, the thing that attracted me to them was the price and the (pardon the pun) flexibility of them.

I have a huge barn they will go on so space is not an issue.

Plus I only paid £39 per panel which I thought was ok.

 

[binky]

42p per watt is pretty good, and anything Japanese is always good - they have a tradition of understating performance in preference to promising maximum numbers and customers being disappointed....

not sure how you fix a flexible panel though, sounds like the sort of thing you use on boats. Love the detail in the spec, they even detail how to pack them in a container...

 

[Barx]

I guess you could argue the fact that the max V when connected is 314.9v. which is well with in the inverter spec. The 429 is open circuit, which once connected to the inverter, obviously it won't be open circuit.

just debating......

 

[binky]

you get some strange effects due to weather, one of the most important criteria is the inverters ability to resist 1000W/m irradiance at -100C - ie sunny day and  snow covered ground. Another interesting effcet is 'cloud edge' whereby the sunrays can be focussed to cause a spike in the panel (I ignored this allowance once on a marginal set-up and ended up having to change the inverter).

 You are correct in that VOc should never happen, but systems can often run at higher voltages than expected. In theory they should be around the Vpp max figure all the time, but if something did short out.....

 

[Barx]

you get some strange effects due to weather, one of the most important criteria is the inverters ability to resist 1000W/m irradiance at -100C - ie sunny day and snow covered ground. Another interesting effcet is 'cloud edge' whereby the sunrays can be focussed to cause a spike in the panel (I ignored this allowance once on a marginal set-up and ended up having to change the inverter).

You are correct in that VOc should never happen, but systems can often run at higher voltages than expected. In theory they should be around the Vpp max figure all the time, but if something did short out.....

Good call...

 

[John Preston]

So after a bit of chat with SMA and a bit more research I decided to opt for the SB2000HF-30 which seems to tick all the boxes on the SMA Design softwear.

The only question that is a bit grey is that of grounding...so a new thread is being opened.