Low Voltage & Charger Efficiency a thread mutation

I haven't done any testing, but I would expect that the various Power Factor Corrected chargers to perform well in low input voltage conditions.
For example: Xantrex TRUECharge, Samlex BP-1210, Sterling ProCharge , ProMariner's ProNautic line, Victron Phoenix, etc, etc...

I do have an IOTA DLS-30 and a Variac sitting around, so I can easily test that one and report back. I do not own a B&D VEC1093DBD, but I expect that it would perform poorly with low input voltage.

Cheers,
-Mark