UPDATE #2:
i let the charger run in float mode for about 4 hours, before shutting it down. it held steady at 13.17 v and 0.3 - 0.4 amps throughout. i took a voltage reading of 13.17 volts immediately after turning it off, but no more readings.
batteries sat all night with a 0.9a draw from the fridge controls for about 8 hours. battery volts were at 12.75 with the fridge still on. i turned off the fridge and let things rest for about 15 minutes. voltage rose to 12.83. i took my sg readings then took another voltage reading of 12.85.
then i turned on the inverter and ran the water pump a short while to clean up. took another reading. voltage dropped to 12.77 with the inverter still on. turned it off and waited about 10 minutes. voltage rose to 12.79, and a while later to 12.81.
these numbers are higher than in the past... obviously bringing the charge current down to 1.9 amps, instead of the usual 8amps (with my 40 ampers), made the difference. i will now have to charge with the pm4b down to 8 amps to see how things compare.
what concerns me is the fact the pm4b kicked down to about 9 amps when it first kicked into the 13.6v absorption mode, and was down to 5.7a charge current within one hour. the other chargers i've used would take several hours just to get down to 8 amps... which tells me they were not doing their job. so even at 13.6v, the pm4b has way out-performed the other higher voltage chargers i've tried.
i took the SG readings at about 63 degrees F. allowing for temp compensation, acceptable readings should have been at or above 1.245, correct? i got 1.275 - 1.280 throughout, except for one rogue cell which came in at around 1.260 - 1.265... still well above acceptable limits. in the past the SG readings have exceeded acceptable levels.
my other concern with the higher voltage chargers is their apparent tendency to boil batteries dry. in fact, in the last 10 weeks i went through 1 1/4 u.s. gallons of distilled water for 12 cells!!! that's almost 2 ounces per cell per week. this is completely unacceptable to me. i think part of the reason for this is the higher frequencies at higher temps, which is a real no no.
what i would like to find is a unit that only does reconditioning, where i'm in complete control, and doesn't cost over $100. none of my chargers have manual recondition mode, but instead have to be in float mode for an extended period of time before automatically doing an equalization. and that's simply not an option for me. in fact, that was one of the perks with the xantrex xpower40 portable... that is until it kicked the bucket like so many portables seem to do :(
i think maybe the pm4b does live up to the name "smart" charger, in that it seems to have kicked into float mode at the very same time the surface charge dissipated down to float voltage, i.e; 13.2v. (see first update). that tells me it's monitoring the voltage drop very closely.
anyhoo, i will do more tests at various states of discharge and re-charge, and keep you informed.
