This would be a handy thing to have, if it works as advertised. I seem to recall there may have been a discussion here about this technology, but I can't find it. Needless to say, I have no commercial connection with the company.

The BatteryMinder is a easy-to install device that connects directly to your battery or battery bank. One BatteryMinder can handle all the batteries onboard. Just connect it to the central (+) of your battery switch and the ships negative ground (-). It automatically sends out high frequency spikes at random frequencies up to 35 Amps in amplitude which effectively knocks the sufanation off of your batteries' plates and desolves it back into the electrolite.

RFP™ circuitry allows the OnBoard desulphator to sweep the entire frequency range known to cause sulphation crystal molecules to resonate, un-bond, and then safely dissolves them. The sulphuric acid, the main component in the sulphate crystals, is now free and returns to the battery’s electrolyte.

http://www.sailorssolutions.com/index.asp?page=ProductDetails&Item=DSUL01