CUSTOMER QUESTION:

Received 30 amp MPPT controller today to connect to my 12V system with input from two 225 Watt PV panels (450W). Instruction book says "maximum nominal input is 400 watts" for a 12V system. Question, can I safely use the controller even though I exceed the maximum nominal value by 50 watts?

MORNINGSTAR'S RESPONSE:

Yes, you can oversize an MPPT controller. Generally, we advise no more than 20% or so. The controller will power shave off that extra 50 watts, but potentially gain more harvest early and late in the day due to the larger panels. Below is a link to a whitepaper that goes into more detail. There's an example of using a SunSaver MPPT with a 240W panel even though the controller limits to 200W. Same principle would apply to all of our MPPT controllers.

Attachments

Morningstar TrakStar MPPT Technology and Maximum Input Power