Any one use one on there boat? Knock on wood I have had my kragens deep cycle in the Tahiti for 4 years, and it has never needed charging.

Battery Minder
5 watt amorphous silicon solar panel
Safely charges-maintains-conditions all size and type starter, deep cycle, maintenance-type, maintenance-free, sealed, gelled, AGM or dry-type batteries.
Allows you to charge and maintain 1 to 2 batteries (12 Volt parallel-connected or two 6 Volt series-connected) at a time.
Automatically removes (dissolves) harmful sulphation using safe, U.S. patented electronic pulse technology.
The unit automatically desulphates both in the charging and the maintenance modes.
Guaranteed to never overcharge any battery, regardless of how long connected.
No need to add water to maintenance-type batteries during long, non-use storage.
Isolation transformer and smart chip technology ensure safe, long-term performance.
Shuts off completely when sunlight is reduced with no drain on the batteries.
Splash proof, conformal-coated circuitry ensures trouble-free life even in high-moisture marine environments.
Allows battery to be stored safely at 0°F to +120°F.
Designed and engineered in the USA.
Built in strict accordance with ISO 9001 Quality Certification.
Full year 100% money-back guarantee takes the risk out of trying this great product.
Five (5) year warranty covers solar controller except physical abuse.
Two (2) year warranty on solar panel excludes physical abuse.
The unit comes with a Battery Condition Indicator that has a push button for testing the condition of the battery.