Calling on Solar Techies
I have been thinking of going solar for some time and decided to pull the plug. My wants are a 400 to 500 watt system. I have four 12 volt batteries with 340ah. I am not planning on changing b...
Forum Discussion
time2roll wrote:
Why did the MPPT charge controller struggle to work?
The MPPT controller itself introduces more voltage drop into the circuit due to the increase in complexity. It also needs more “voltage-overhead” to operate than the PWM controller due to the ‘switching’ circuit within the MPPT controller. So when the voltage drop along the cables becomes significant the MPPT cannot function as expected.
When the voltage overhead is not high enough for the MPPT to function correctly it reverts to PWM operation.
The MPPT controller also reverts to PWM operation when in absorption or float modes. During these two important charge modes the controller must reduce the current to the battery to avoid overcharging. So in these critical stages of charging the MPPT function has no benefit.
https://sunworks.co.uk/improve-mppt-charge-controllers
Who ever wrote this has no clue what they are talking about. The controller does nothing to regulate the current during absorption of float - in both these phases of the charge it is the battery limiting the current, the controller regulates the voltage. You will note in the settings for your controller there is no limit for absorb or float current, only voltage.
The MPPT may have no benefit if the battery is drawing less current than is available from the panel at absorb/float voltage. However if the battery is drawing more current than is available from the panel at absorb/float voltage then MPPT will help.
Many PWM charge controllers don't measure current at all - they are only regulating voltage.
