Adding solar panel

[soon2befree]

I have a 36 volt 180 watt panel that was given to me tied into a 30 amp renolgy mppt controller. Is it possible to tie a 12 volt panel into the controller

[John Hilley]

How large is the 12 volt panel? It is possible to put them in series, but there are a lot of limiting factors that may not make it worth while.

[ArtJoyce]

Think of the solar panels like battries. Series or parallel; Series the voltage will be the sum of all the pannel's the amps will be the amps of the lowest pannel in the series. Parallel the amps will be the sum and the voltage needs to be the same. So series is the only option.

So to answer your question it depends. Depending on the amps of the 12v panel you could lose watts or you could gain as much as 33% more watts. You need to know the amps of amp production of the panels are.

Example we know the 180 watt panel is peak at 36v. Using the formula for watts watts =volts x amps. The panel develops 5 amps at peak. So at peak 5 amps or more on the 12v you will gain 33% more watts and peak amps on the 12v panel below 3.75 amps you will produce less then 180 watts. 48v x 3.75= 180 watts. So it depends how you mix and match.

[vsheetz]

https://solarpanelsvenue.com/mixing-...0the%20problem.

[ByeTheWay]

Originally Posted by vsheetz

https://solarpanelsvenue.com/mixing-...0the%20problem.

Good Info
Thanks

[DavidEM]

Originally Posted by soon2befree

I have a 36 volt 180 watt panel that was given to me tied into a 30 amp renolgy mppt controller. Is it possible to tie a 12 volt panel into the controller

No. All panels tying into a controller must have the same voltage. Otherwise the controller will select a voltage between 12 and 36, that maximizes power output. That voltage will probably be too high for the 12V panel to provide any power.

36 volt panels are rather unusual, particularly less than 200 watts.

David

[Persistent]

Some panels have built in controllers. The 12 volt panel may be one of them. If so, connect the built in controller directly to the battery.

Panels of different voltage will work efficiently if each is on its own controller. Some older panel designs will suck down higher voltage panels. Check with panel manufacturers for compatibility. At best, the 12 volt panel will contribute little to nothing to the output of the controller. At worst, it will draw power from the 36 volt panel.

Measured voltage on the 36 volt panel will drop as the controller draws more power. It will have to drop below the output voltage of the 12 volt panel before the 12 volt panel can possibly contribute.

https://www.renogy.com/content/RNG-C...040-Manual.pdf

I skimmed the manual. I did not see where it addressed your question. It seemed to assume there would be one solar array using matched panels.

I wish you good luck and happy trails ahead!

[John Hilley]

Originally Posted by DavidEM

No. All panels tying into a controller must have the same voltage. Otherwise the controller will select a voltage between 12 and 36, that maximizes power output. That voltage will probably be too high for the 12V panel to provide any power.

36 volt panels are rather unusual, particularly less than 200 watts.

David

They can be wired in series and use the same controller, however you will be limited to the current output of the lower current panel.