Hi there, question about some panels

[thinkslaughter]

Ive come across some solar panels but im not sure if they are worth purchasing.

basically they are big (26 x 48 inch) 42 watt panels, manufactured in 2001 but never used.

I checked them out and they seem to be meant for grid connect panels, but i cant find any info on the web about them.

They have a sticker on the back that says

'BP Solar' 42 watt

part number: 900275.

class 2 max sys voltage 250v
ul max sys voltage 117v

Do you think these panels would be good for $100 each? And maybe could be used for a DIY project, or no?

[Mike90250]

You should be able to go to the BP site, and look them up. Were you able to try that ?

[Mike90250]

Is this close:

http://www.bp.com/sectiongenericarticle.do?categoryId=9019644&contentId=7036973

[thinkslaughter]

Is this close:
http://www.bp.com/sectiongenericarti...tentId=7036973

Those are the closest i could find, and some 43 watt on another site called bp millenia.

here is a picture of the panels im looking at.

And thanks for the reply!

[Aussie Bob]

$100 for a 42w BP panel seems a good price. I'd go for it.

[Mike90250]

Those are the closest i could find, and some 43 watt on another site called bp millenia.

here is a picture of the panels im looking at.

And thanks for the reply!

Those pic's don't show any logos - I'd be a bit concerned about a knock-off copy. I can't tell, is that a sealed panel with a frame ?

[q280]

$100 for 42watt solar panel is not so cheap, i can supply you $76 for it and with ce/tuv/iec61215,61730 certificates

[thinkslaughter]

Those pic's don't show any logos - I'd be a bit concerned about a knock-off copy. I can't tell, is that a sealed panel with a frame ?

No they dont have frames thats what i was worried about.

i found a thread from 2006 here: seems they have a high failure rate.

[Mike90250]

No they dont have frames thats what i was worried about.

Well, there's your answer. useless. why bother setting up, if they are going to get wet and fail. You might as well bake them in the sun for a couple of days, and when they are good and dry inside, run a fat bead of silicone seal around the edges to seal them and buffer the glass edge.
You must use the electrical grade sealer (acetone cure) not the household grade (acetic acid cure). The household grade will trap the acetic acid inside and corrode the panels out.

[gwest77]

BP panels

Here's my two cents worth that I found. BP never sold the 900275, they only used them on their own gas stations as a development effort. "This came from a contact with experience with these panels." I have a lot of experience with this particular panel as I lived off the grid for a year using 40 of them. My peak output was 1.3kW or 30W/panel which corresponds to the 30% degradation that can be expected with amorphous silicon in the first few years of use. I can help you with an inverter if you like, I modify computer battery backup systems to function as solar inverters. You should use a 48 V nominal system, your actual working voltage will fluctuate between 50-56V depending on the charge state of your batteries and the solar exposure.

[grieker]

48v

Why should I use 48 volt battery array vs 12? Will 4 12 volt batteries in parallel run longer than 4 12 volt batteries in series? Is that why? It seems more expensive for components when choosing 48V

Thanks in advance.

[ppsadrian]

Need to identify these panels also!

Those are the closest i could find, and some 43 watt on another site called bp millenia.

here is a picture of the panels im looking at.

And thanks for the reply!

Hi there, I am working on a project that also has these panels. I don't have access to them as they are in another country, but I need to use them in a refurb. I need the VOC Vmax, ISC Imax.

Adrian

[Sunking]

Why should I use 48 volt battery array vs 12? Will 4 12 volt batteries in parallel run longer than 4 12 volt batteries in series? Is that why? It seems more expensive for components when choosing 48V

Efficiency and power limitations. 12 volt systems are fine for toys and RV's, but not practical for household use unless we are talking about very small loads in which 1 string of a 12 volt battery can handle

[ppsadrian]

12v vs 48v

I agree.

The current halves every time you double the voltage, and it is the current that determines the cable & fuse sizes due to volt drop. This is the expensive part.

So if you are running a 3kW load, you will have 1/4 the current (and 1/4 the cable, switch gear & fuse capacity requirements) at 48vdc that you would at 12vdc, to do the same work.

Parallel batterys can also fail quicker, as one faulty low resistance cell will bring down the entire bank. Fault currents are also higher.