MPPT vs PWM test

[markopolo]

I did quick test to compare the output from a 40A MPPT (Tracer A clone) and 30A PWM solar controller today.

The solar panel specs:
170W
Vmp: 19.01V
Imp: 8.91A

Early afternoon summer sun. Panel pretty much parallel to the ground. 13A load on a 12V lead acid battery.

MPPT controller output 11.7A to 9.7A
PWM controller output 8A

Output current measured using same shunt for both tests.

All equipment including the panel was brought out from air conditioned storage and I suspect that helped get the 11.7A early results. Very hot & very high UV & no cloud cover today. PWM controller was tested second and then I tested the MPPT controller again and got 9.7A.

Looks like I can say that the output was 25% greater using the MPPT controller as it was most often around 10A compared to 8A from the PWM controller.

This is basically common knowledge but still interesting to me to do a direct comparison.

Looking at cost / value / output is interesting. If working within a budgeted amount then adding an additional matching panel would result in more energy being harvested than upgrading to an MPPT controller.

If the van roof is already maxed out with panels then an MPPT controller is a nice upgrade.

[GeorgeRa]

Great data, thank you. I don’t have actual numbers but recall that MPPT were much more expensive than PWM charge controllers. This price difference is lower today so it really makes sense to go with MPPT with a new solar installation.

[W9TR]

Thanks - great info.

[booster]

Good test for sure. It is always useful to do a confirmation run on all the "rules" that are said to apply and separate the true from urban legends (which we have seen some of when tested and closely looked at).

[SteveJ]

helpful info, thanks.