"unbalanced" panels ?

[SoulRaven]

Hi, I have a 100 watt Renogy panel, and a 200+ panel due to the kindness of our friend Jim.  

I'm not entirely sure what's the best way to connect them to the controller.  Series or Parallel?  I could get another 100 watt panel and wire the 2 100 's in series , and then connect them in parallel.  It would still be unbalanced, but less so. 

I'm sorry if this has been asked and answered before. You can all beat on me if I make it to the RTR in January, or at least use harsh languague...    

Am I out in the north 40 here?

 

[jimindenver]

They will have to be on separate controllers.

 

[Optimistic Paranoid]

They will have to be on separate controllers.

I take it, then, that they are widely different voltages?

 

[B and C]

If the controller can handle it, they could be wired in series.  Would have to add the two output voltages together.  This would probably require a MPPT controller, but not sure.  I have never worked with a PWM controller.

 

[blars]

If they have the same (or close) Vmp (maximum power voltage) wire them in parallel.
If they have the same (or close) Imp (maximum power current) wire them in series. (MPPT controller only)
If you have a PWM controller, wire them in parallel.

If they are both different, you may get more power from the larger panel by itself than trying to use both with the same controller.

 

[frater secessus]

AltE has several videos testing these scenarios.  Her findings basically line up with Blars' advice.

 

[SoulRaven]

I take it, then, that they are widely different voltages?

I set up the 200+ one Saturday, and using a multimeter, read 35 volts off of it. I was surprised, pleasantly, but realized that my other one, the Renogy 100 watt puts out somewhere around 18 volts (it's at my friend's house about 70 miles from here, or I'd test it) 

I DO have a Renogy MPPT controller ... 

If they are too unbalanced, I'm thinking of using the one I got from Jim, and keep the 100 watt as a backup .. or as I said in my Original Post, add another 100 watt and wire the 2 100 watts in series and then add that pair and the 230 in parallel.

 

[SoulRaven]

AltE has several videos testing these scenarios.  Her findings basically line up with Blars' advice.

Thanks to all who answered... this video is exactly what I was looking for ...

 

[flying kurbmaster]

in that video they wired two 24 volt panels you have a 12 volt and a 24 volt panel I think you will need two controllers, someone with better knowledge can correct me if they like.

 

[jimindenver]

The big panel is a CanadianSolar 220w mono. It's rated for 36v but I have seen it go over 40v on a cold day. Putting a 12v panel in series with it will cut its voltage to that of the 100w panel and as mentioned, it is more powerful on its own. So put the MPPT controller on the big panel and get a inexpensive PWM controller for the 100w.

 

[SoulRaven]

The big panel is a CanadianSolar 220w mono. It's rated for 36v but I have seen it go over 40v on a cold day. Putting a 12v panel in series with it will cut its voltage to that of the 100w panel and as mentioned, it is more powerful on its own. So put the MPPT controller on the big panel and get a inexpensive PWM controller for the 100w.

That makes sense.... thanks, Jim!

 

[frater secessus]

in that video they wired two 24 volt panels you have a 12 volt and a 24 volt panel I think you will need two controllers, someone with better knowledge can correct me if they like.

She has several videos in the series.  I linked to the first one I found assuming OP could find the relevant ones in the Recommended sidebar.