Desulphators are supposed to shock or shake the sulphate crystals off the plates with a high frequency pulse maybe about 4 megacycles. It is more myth than actual and nothing that I have found has shown to work, I have assembled one as a test to prove that it made no difference. The use of a high frequency pulse soes nothing to improve sulphated batteries, though there has been a lot of snake oil sold for this purpose.
Proper use of trickle chargers associated with desulphaters are responsible for keeping batteries in better shape than ones allowed to sit in a partially charged state. Photovoltaic battery systems condition and balance batteries to make them last longer and no desulphators are functional or recommended in these large battery arrays. If its too good to believe......
Enjoy, Woody
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Life is short, eat your dessert first .......In theory there is no difference between theory and practice. In practice there is. Yogi Berra