[coding123]

I did this for a year on my previous macbook and it destroyed the battery. The inverter creates cleaner power. Good luck finding a quality one that can handle the voltage changes from 14.6 -> ~10.5 the battery is going to spit out with the MPPT attached..

[nomel]

Maintaining a regulated voltage with input voltage changes is a primary feature of a DC-DC converter, like a boost converter. With a buck-boost converter, you can maintain a regulated voltage when the input voltage goes above or below the output voltage.

[stephen_g]

Wait, you tried to do it without a DC/DC converter to regulate it? Sounds like a bad idea.

A good off-the-shelf isolated DC/DC converter that would clean it all up and give you a nice, consistent, filtered DC voltage should be able to be had for $100 or a bit less.