backchannel: “dropping to bulk”

_frater secessus Wrote: After Bulk (assuming no significant load) the controller is no longer tracking the Maximum power point (mppt).    It is tracking whatever sub-maximum power point provides the correct amount of power required (PPT).  So in a very narrow sense the manual is correct: the PPT is no longer tracking M PP.  But in the way people generally understand the term "MPPT" the manual is misleading.   Add enough load and the controller will track MPP no matter the charging stage. _ _If we want to know what the controllers are doing in Absorption and Float we will observe the volts/amps going in and out of them in those stages.   Make the observations and let the chips fall where they may._ **because when the load is added it drops the voltage into the bulk setpoint. be it 13.4v or 14v or wherever you want to put it. the point here is're not getting extra charge outside of bulk. It cant use it, it doesn't use it.**

FFS, this is precisely the kind of misconception that can be rectified with simple testing.

  1. start with the system in late Absorption.  Observe volts and amps in and out.

  2. add a load to it

  3. watch the controller increase power up to Pmax without dropping to Bulk

  4. recant

The controller will hold the setpoint as long as it can meet demand.  If the controller is pumping Pmax 200W and the demand is 200W then it will hold the setpoint while running the panels at Vmpp.

I am losing confidence that people actually want to know how this stuff works.  Call it voodoo if you want, just don’t lead others astray with unfounded bullshit.