Landyacht it does not hurt to ask. No need to lie about the situation, but ask if they will cover it under warranty in your situation.
Mex it may be that most of the desulphation benefit is Simply equalizing, but I too have had very good luck keeping batteries running a long time with my 5+ year old Schumacher desulphating charger. Using only the E450's alternator, maybe 30% of its life on a 5 W solar charge maintainer in the windshield, and monthly desulphating (and no equalizing), I got over 10 years out of the OEM Motorcraft battery.
Had a battery die in the Texas heat in our G6. Desulphating brough back a little life but I never could get it back the way the batteries in Michigan used to recover. Likewise it Was no go on recovering an AGM battery that had dropped it's output to around 60%. But for all the Dozens of other batteries in cool climates I have tried it on it has been absolutely amazing. Proper equalizing as you describe above may have had the same result.
Jim
