Solar controllers wired in parallel

[DanNJanice]

Has anyone tried wiring the output of two solar controllers in parallel? There is quite a bit of buzz about this online, however, I am not convinced it would not damage the controllers or cause them not to charge correctly. It does solve the dis-similar solar panel problems and allow you to use a mix of panels without losing efficiency.

I reached out to Renogy and asked them about it.
Here is their response:
Thank you for contacting Renogy.

Please do not connect different sizes of solar panels to the same system, otherwise it will not only reduce the efficiency of solar panels but also affect the normal use of solar panels.

We also do not recommend using two controllers in parallel, which can lead to confusion in the charging data of the controllers and thus affect the normal use of the devices.

I plan to contact the other big players and see what they say.

 

[Oregon_Camper]

Series or Parallel....does not matter. You just need to confirm your controller can handle the increase voltage/amp (depend on how you wire panels)

Mixing panels of different sizes (voltage) is never considered a good idea.

 

[DanNJanice]

I have done a little more research on this. Victron and Morningstar both approve of connecting their controllers in parallel. So I will go with one of those companies.
I am not planning to mix the panels, I am planning to keep the panels isolated from each other by using two controllers. That way I will be able to use my existing portable panels along with the roof mounted 320W panel. This design will also allow me to connect my portable panels in parallel to improve resistance to shading.

See below:

 

[Oregon_Camper]

Multiple controllers is always a great solution.