Mixing Solar Panels

Are you killing the output of your solar array? In this week’s podcast, Wes and David discuss the problems you might face when mixing different solar panels into one system. It’s not uncommon for homeowners to add solar panels to their current solar panel array as budget allows. Be sure to listen to our podcast to find out how you can still get maximum production with mismatched solar panels.

So, what’s the big deal? Isn’t it just simple addition?

Not exactly. Your solar array is only as strong as the weakest panel. That’s right, connecting a panel with a lower output to the array drags the power output down.

Here are some tips to make it easy to understand

• Connecting different solar panels in a single array is not recommended: You may reduce the voltage or current which leads to lower wattage output.
• If you can’t pass up a bargain, try to buy solar panels with similar voltage and current.

Charge Controllers:

• Connect each “sub-array” to its own charge controller, or find a charge controller with multiple input feeds. Then combine the arrays by connecting them to the same battery bank.
• Connecting mixed panels to an MPPT charge controller may confuse the controller and make it impossible to determine the ideal operating voltage and current. Instead, you’d do better to save by purchasing multiple PWM controllers.

Grid Tie Systems:

• The best practice is to wire each array to its own grid tie inverter, wired into a breaker in your fuse panel.

Wiring in Series:

• If your solar panels are the same current: Wire them in series.
• When wiring in series (increases voltage): all panels will produce the same current of the lowest panel.
  • Two 8.5 Amp panels wired with an 8 amp panel will produce 8 Amps.

Wiring in Parallel:

• If your solar panels are matching voltage: Connect them in parallel.
• When wiring in parallel (increases current): all panels will operate at the lowest voltage rating.
  • Two 40 VOC panels wired with a 30 VOC panel will produce 30 VOC.
• Need help with solar panel wiring? Watch our Solar Panels for the Beginner Video.