Yet Another PWM vs MPPT Comparison Test

12thgenusa wrote:

BFL13 wrote:
You could lower your solar float to 13.2v and get some (but only a little) MPPT advantage at that voltage instead of at 13.8 or whatever.
"Depends" whether that would be worth the bother most days.

On most controllers, MPPT is only operating in bulk mode, not Absorb or Float. Rogue in fact calls bulk mode, MPPT mode. Changing float set point would have no effect.

I may be mixed up in what is possible here.

The Eco-Worthy MPPT controller is the same. It gets the batts up to the chosen set-point say 14.8, then drops out of MPPT and goes PWM to the chosen float set point. No time seems to be spent at "absorb" before going to float, although it says absorb for a second there if you don't blink! It may just be my set-up where the batts are near full by the time they hit 14.8.

What I was thinking was the scenario where you are running loads near max amps of the controller after getting the batts to 14.8 and it drops to float would kick it back into bulk so MPPT.

But the batt voltage has to drop below 13.2 before it will go back into bulk. The "loaded voltage" on the nearly full batts would have to be below 13.2 but that would not be your "float voltage"

How about if the idea is to run loads all day you get the batts charged up using the high set point at 14.8, then add the loads to knock that voltage back down below 13.2, then reset the high set point (not the float setting) to 13.2 so it doesn't go back up on you when the loads are not so much from time to time?

Then you have to reset that to 14.8 for next morning. Anyway you are right-- it doesn't work like I was thinking.