Dave - I have a Battery Minder from VDC and have used it for two years. I have four batteries hooked up to it for the winter and it it works great! As for the desulphation snake oil - I no longer believe it to be snake oil. Last fall the 3 year old battery on my wife's VW diesel went bad. Four cranks and it was dead. Voltage on it was 11.80 volts. Charged it up and voltage hit 12.25 volts but same thing four cranks dead. Bought a new battery and all was well. Just for the heck of it, I took the old bad battery and hooked it up to the Battery Minder and put it in desulphation mode. Of course as you live life you forget things. I forgot that I had that battery hooked up for 5 months. So I checked the voltage on it 13.09 volts. Hey this thing has life!!I disconnected the Battery Minder and let the battery sit. Forgot about it again for 2 weeks. Checked the voltage on it 12.82 volts!! This battery is good again! It now is in my daughter's car and works just fine. I now am a firm believer in the Battery Minder. By the way - I also have the 6 volt version for my 1930 Chevy battery and that battery is still like new after sitting on this thing for 2 years. Hope this helps you decide.
Morris