Here is an interesting tidbit that gives a little insight into the Die-Hard Platinum-specific battery charger that I referenced above...taken from the Sears site listing "Reviews" (noting there are also negative reviews in the same section). I was hoping to dig up a more specific version of the Platinum-specific algorithm...will keep looking.
Here is the review:
"Our most helpful positive review
15 people thought this was helpful.
71227 is top of the line April 07, 2009
I tested the 71227 charger, and like it. The meter accuracy
is within 0.05 volts, and the charging algorithms appear to work quite well,
although they are not described in the instructions. I observed that the voltage
was generally limited to 15.5 for regular, 16.0 for deep cycle, and 14.7 for AGM
batteries. The 40 amp capability is in the form of a long timed pulse of about 2
minutes followed by 15 amps for a similar time period, then repeating until the
voltage has risen enough that it isn't required. The amperage isn't constant, it
tapers down to limit the voltage in typical CC/CV fashion, although the
algorithm appears to actually be more complex. For instance, on a particular AGM
battery it went to 15.5 volts near the end of the charge (95%) with current at
about 1.5 amps for about 30 minutes and then stopped (completed). I suspect that
this was an automatic attempt to condition the battery. A Schumacher SC-800A
charger (Schumacher actually makes the DieHard 71227 charger) did the same
thing. After three discharge cycles, it stoped doing the "high-voltage
treatment". Also, in AGM/DieHard Platinum mode it went to 15.5 volts briefly
during one of the 40 amp cycles. Although the instructions for DieHard Platinum
(Odyssey) say to choose a charger with <14.8 volts, this charger was
obviously designed with these batteries in mind. The only negative I noticed was
that if the AC power cycles, after 15 minutes it will come back on as a charger
set for regular battery mode and set for 2 amps. I wouldn't recommend leaving an
AGM battery connected on maintenance mode. Overall, it's a nice charger. I hope
some of the tech info above helps."