Mixing sizes and brands of solar panels?

[66788]

I have a Kyocera 120 watt panel and an older American made 85 watt panel and wondered if I could wire them in parallel to the controller for a total of 205 watts. The output voltage is within 1 volt of each panel.
I have a MorningStar ProStar 30 amp charge controller and a single 12v deep cycle battery. (this is for the Ram van and not the Grumman Olson)

I haven't read anything about mixing panels on this site and it might be on a lot of peoples' minds.

thanks

 

[LeeRevell]

A couple (at least) other members do have dissimilar sized PV panels, so it looks you have the basics of a good system.

 

[akrvbob]

I believe you can mix sizes no problem, but you can NOT mix voltages. So make sure the voltages match and you should be okay.
Bob

 

[RogueRV2]

I have 3 different types of panels and 11 separate panels in wired parallel. 9 panels are 10 watts each, an old 80 watt panel, and one 100 watt Renology panel. The old panel has the lowest voltage, yet watss are watts and the system performs as the math predicts. A more important consideration is length and gauge wire used to connect the panels that will limit the voltage drop to under a 2% loss.

 

[SternWake]

I've read on AZ wind and sun forums panels of different wattages can be paralleled, if their VMP, voltage at max power figure is within 10% of the others. but perhaps that was OCV, maximum open circuit voltage.

I am running a kyocera 130 watt panel and a unisolar 68 watt panel in parallel. Each has their own wire run to the controller. I'll get 13.5 amps June 21. Sept 21, I got 11.5v, with them more or less flat on my roof.

Am not sure about panels wired in series. I'd guess if the MPPT controller can handle the combined voltage of the two different panels, then there is more leeway in panel voltage specs. But that is a guess.

 

[akrvbob]

I had a 140 watt 18 volt panel on my van and needed to add more so I went into Northrn AZ wind & Sun and got a great deal on a 240 watt panel for $240. But it is 36 volts. They told me not to mix the two together so I had to buy a new controller even though my old one was 50 amps.

I didn't mind, I prefer seperate discrete systems for redundancy.

On the other hand, on my trailer I have a Kyocera 55 watt and Kyocera 140 watt in parallel and they have never been a problem of any kind. But they are both 18 volts.

The voltage is the key consideration!
Bob

 

[highdesertranger]

I have also heard of the 10% difference although I can't remember where. I am going to have to look into this. highdesertranger

 

[countessj]

If I mix panels, do i need to charge controllers and inverters? Boneheaded of me not to have thoughgt this through earlier.

 

[B and C]

Solar panels that are not electrically the same each need their own charge controller. Your inverter should be connected to the battery bank so you shouldn't need more.

 

[izifaddag]

I have a Kyocera 120 watt panel and an older American made 85 watt panel and wondered if I could wire them in parallel to the controller for a total of 205 watts. 
I have a MorningStar ProStar 30 amp charge controller and a single 12v deep cycle battery. 

it makes zero difference. The controller see voltage and current it has no idea which brand of panel you have. Likewise there is no 'balancing' involved. It is unlikely that you will ever see 120 or 85 watts from the panels. The numbers they quote are ideal lab conditions never to be achieved in the real world.
You will see voltage wander up and down depending on the amount of light hitting the panels. I had a small panel I bought for experimenting with. I played with the light source with a volt meter hanging on it just to see what would happen. It went up and down like a yoyo.
The important thing is how much current your controller is rated at. I have 2 x 100 watt panels and the controller is a renogy rated at 40 amps. That will be plenty even when I add 2 more panels.
Don't worry sir you are fine.