mppt vs pwm

Salvo wrote:


I see no real advantage when using a higher Vmp. Temperature still reduces power by the same amount. 90's thinking still apply.

The difference between Vmp and battery voltage is directly proportional to the gain you would expect to see an MPPT controller provide. The greater the difference, the greater the advantage will be for MPPT over PWM. With the higher voltage arrays that are common now, the gain with MPPT could be several hundred percent or more over a direct connect/PWM scenario. The issue here, of course, is that connecting a higher voltage array directly to a lower voltage battery is going to drag the array's voltage down to that of the battery's. A 40v Vmp panel attached to a 12v battery, for example, is going to exhibit a loss in power that is several times lower than what it would be producing at its Vmp. Imagine a 100v array, or 400v array (as is now possible). The 17v Vmp --> 12v battery scenario is old news, and so is the talk of 10% gain (or 8%, if you like to nitpick). Time to let it go.