Re: (ET) MPPT?

["subscriptions aeolusdevelopment com" <subscriptions aeolusdevelopment com>]

Perry Cain Wrote
>Didn't want to hijack the Solar Power Thread.  But what is MPPT, and why 
>is
>it good to have?

Maximum Power Point Tracking.  

The simple explanation goes as follows.  The voltage developed from a PV
solar cell depends on the current drawn from it (or vice versa).  For
example
   At 1A you might have 2V giving you 2W
   at 1.5A 1.8V for 2.7W
   at 2A 0.8V for 1.6W

Clearly in that case you want to draw 1.5A to get maximum power from the
cell.

Maximum power point trackers are essentially DC-DC convertors that load the
solar cells to the point where you get the most power from them converting
the output to the level that best suits the output load (following the
battery charge curve if hooked up to batteries).

Since the maximum power point varies with light level and cell (probaly
less with cell now than it used to) a MPPT tracks the point dynamically.

Robert

--------------------------------------------------------------------
mail2web - Check your email from the web at
http://mail2web.com/ .