Les, charger advertizing and promises of "hope" are as bad as oil additive snake oil ads. I am amazed what junk some of the well known charger manufacturers sell, and high priced at that.
We tested several chargers here at our Defense labs and the Xantrex TrueCharge 2
was by far the best. We bought a slew of them. And when I say "tested", we tested all aspects of them; current, voltages, temperature compensation, fault and alarm indications, etc.
They are available in various outputs. Note only the 20, 40 and 60 amp units can take a remote battery temperature sensor (most chargers put them in the charger
) and the remote panel enabling you to reduce the max current rate.
These aren't toys and as a result cost a few hundred dollars. But they do handle all types of batteries: FLA, AGM, GEL, Pb-Ca.
I have some pics here
From the home of the plain old low-tech flooded lead acid battery, now in its 14th year and still starting my car at -20F.