Quote:
Originally Posted by Daox
BTW, what is an MPPT charge controller?
|
This. Multi Point Power Tracking. You know how PV panels make waaay over faceplate voltage, especially in cold weather? My 24V panels make 35-38VDC some days, at the controller. A 'dumb' charge controller like the Trace C60 just lops off the excess voltage. But an MPPT controller holds the PV voltage just a little above the battery bank (or grid-tie inverter) demand; the surplus voltage it converts to amperage, resulting in 15-30% additional Ah storage.
If you have 10 panels, MPPT is like adding two or three additional panels. A good MPPT charger is about $400 more than a 'dumb' one. Blue Sky and Outback are the big names in MPPT; Morningstar just released a smaller, more affordable unit; and Midnite Solar's 'Classic' is gonna be the schnitz when it's finished.
PV uses 'Buck' MPPT, where the voltage is chopped down. There is also 'Boost' MPPT, which
raises voltage while sacrificing current. The Bergey XL1 wind turbine has a Boost controller, so in winds below 14 mph it's still putting amps in the batteries, albeit reduced amps.