So just EXACTLY WHERE on that link does it back your claims?
One statement it made was "DC voltage is constant."
Anybody working on charging systems on small engines, that are only equipped with a diode, knows that you are getting a PULSATING DC!
AC means the voltage ALTERNATES between negative and positive.As long as it meets those requirements, it's AC. IT DOESN'T HAVE TO BE A PURE SINE WAVE!
With this posters system, who knows what kind of AC waveform may be present! It may be going 2V positive and 30V negative. It may be "spikey", sawtooth, sinusoidal or some combination thereof!
The point is that it's AC and therefore has a negative component. The negative part is going to try to "reverse charge" the batter to some degree.
A cheap meter will show that there is an AC voltage and that's what matters. It doesn't matter how PURE the AC waveform is.
I'll trust myself on that!
Google "Sea Tech Transmissometer". Guess who built them for 16 years?