150V 45A MPPT - roll your own


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poida

Guru

Joined: 02/02/2017
Location: Australia
Posts: 1425
Posted: 07:59am 15 Feb 2024      

it's been a while since I've looked at this part of the code.

separate tolerance settings exist for absorb and float.

the idea is that at some time, BV will get to the absorb setting.
this means it will no longer care about MPPT and just maintain the battery at
absorb voltage. this is because there is more than enough solar to keep the
battery at absorb voltage.

And when it first gets to absorb voltage it starts a timer.
The timer sets how long to have battery at absorb voltage.

the timer will count down while BV > (absorb voltage - absorb_tolerance)
this is to allow for inverter transient loads and minor clouds and such.
No point in bailing out of absorb mode just because a fridge switched on, dragging
BV down 3 volts.

There is an absorb time setting. This has to be achieved before float mode will be enabled.

so, lets say float mode is finally enabled. Again, BV needs to stay above (float - float_tolerance) to remain in float mode.
if BV is less than (float voltage - float_tolerance) then it goes back to MPPT mode
and it's likely to quickly then go to absorb mode.
Edited 2024-02-15 18:01 by poida