Desulphator: Saves Batteries

When I first started learning about boats’ systems, I was horrified at the complexity of keeping battery banks alive. It seemed like there were so many ways to kill a battery by neglect or abuse or just looking at it funny, that we ought to just throw up our hands and go back to oil lamps and hand crank starters. To compensate we’ve got big alternators, fancy regulators and multistage chargers that cost considerably more than the batteries themselves. Still, good old lead acid batteries have an Achilles heal that tends to kill them sooner or later, and that’s sulphation. Basically, when a battery is discharging, lead from the plates is converted into lead sulphate, and while charging, the sulphate is converted back into lead. The problem is that lead sulphate can form into crystals while the battery is discharged, and the crystals keep it from changing back into lead, and this results in a permanent loss of capacity. The traditional remedy for reduced capacity has been to do an equalization charge—a higher than normal voltage charge that can dissolve the crystals, but a procedure that requires close attention and some caution. Unfortunately, an equalization charge can cause permanent damage to sealed batteries such as gel cells and AGMs. An interesting option is a desulphator, an electronic black box that is attached to the battery terminals, and gives them brief, high frequency zaps, causing the lead sulphate crystals to dissolve. Users report being able to bring some old, dead batteries back to life, and considerably extending the lives of their battery banks.

There are plans on the web for those handy with a soldering iron, and a number of vendors are making electronic versions, some of which show up at the boat shows. Even some of the Vector automotive battery chargers have a desulphating setting to recondition cranky old batteries. Given the cost of replacing a substantial battery bank, another $100 or so for a desulphator could be pretty good insurance.

Links: desulphator forum