Adding another solar panel (1 Viewer)

[BusyBuilder]

If I have an unknown solar panel and want to add another will I have any problems ?

can I tell what power output the existing panel is by the (actual) size of it ? or do I need to find the sticker on the underside of it (if I can) ?

The solar will supply lithium batteries, when I get around to having them installed.

Please don't ask me to use a multi meter, I'm a joiner LOL!!

 

[headlight]

If I have an unknown solar panel and want to add another will I have any problems ?

can I tell what power output the existing panel is by the (actual) size of it ? or do I need to find the sticker on the underside of it (if I can) ?

The solar will supply lithium batteries, when I get around to having them installed.

Please don't ask me to use a multi meter, I'm a joiner LOL!!

Can you get a mobile phone under the panel ?
If you can you can put the phone on video, move it around under the panel and hopefully video any stickers.

 

[RogerIvy]

If you measure the voltage and it’s similar to a new panel you could place them in parallel.
I wonder if an industrial endoscope camera could enable you to read the label.

 

[Jev88]

Worst case run new cable and separate controller for new panel and leave old one alone?

 

[Jofang]

We had 120W solar and added another 400W. Used new cable and controller, as suggested by Jev88 above.

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[Guigsy]

Generally you should try to match panels to get the best out of them. Different panels can have different characteristics, depending on the type of cells within the panel. When joined in parallel, the voltage of the lowest panel drags the rest down.

I'm about to add a pair of 100w panels to an existing 175w. I know that the new panels produce about half a volt less at peak output and at open circuit. So I'm going to get about 95% of the power, only a small loss.

But bigger mismatches can sometimes mean that connecting an old panel to a new matched array of a few panels can decrease the efficiency so it's actually worse that just scrapping the old panel. The most efficient thing to do is to add another controller... But that means more holes in the roof.

 

[DABurleigh]

I'd view it as an opportunity to build in redundancy - just use a separate controller.

Dave