Mixing Panels?

[OlJarhead]

OK, I was looking at solar panels and began to ponder this question:

The panels I bought and installed do not appear to be available anymore.  Assuming they do not become available again, and if I wanted to add more power to my system, would it be possible to add another panel of similar but not exact specifications?

For example I have three 205 watt panels and found a similar 205 watt panel as well as a 210 watt panel.  Voltages and amperage's are not exactly the same.

3 x 18.2Vmp/11.27Imp panels plus 1 x 18.7Vmp/11.23Imp panel?

At this point I'm not desperate but it was a thought I had.
Thanks

[Native_NM]

My brother has a Harbor Freight panel and a surplus Siemens panel hooked together (somehow) at his "Kyzynski" shack as we affectionately call it. I'm saying yes. 

[OlJarhead]

According to Jeremy at SunElec you can mix panels as long as they are within 10% of each other.  He tells me that if you are running them in series and the Imp ratings are within 10% you will be fine though it is also best to have voltages within 10% too.

So, if I wanted to get another 205watt panel to bring me up to 820watts of charging power I could do so for under $300 right now....I might be doing this soon then

[MountainDon]

Right. When adding in series try to get the Imp (max power current/amps) as close as possible.

When adding in parallel try to get the Vmp (max power voltage) as close as possible.


If adding to a series set of modules be certain the Voc of the series does not over volt the charge controller. A "hard to go wrong" rule is to total the Voc and then multiply that by 1.25 and then again by 1.25. (Or 1.56 once) No guarantees, but that is the best rule. That will cover the spikes that may occur on a really cold day.

Of course also watch the amps if connecting extra modules in parallel. Use Ioc for that.