Battery desulphators...do they work?

I am in the marine industry here in Fort Lauderdale. I don't know of anyone, and I mean anyone that uses them. I think like a lot of products, they aren't worth the money otherwise yachts would be using them. But I have no real world knowledge with them. Although most of the times I've had to replace battery banks was due to a dead cell and I don't think the product you're talking about would prevent that.

You lose one of the cells and it will no longer function at 12.8 volts and instead of getting say 12.8 volts out of a 12 volt battery, you'll get 11 volts. If also left off of a battery charger it will deplete the battery of electricity pretty quickly, another sign is when you hit it with a load tester the voltage will drop considerably instantly. A dead cell will usually drop the voltage of the rest of the cells around it.....and rob the power from them.. like an internal short.....

And once you get a dead cell in a battery bank, you had better replace the whole bank. Putting one new battery with several aged ones is a really bad idea......I had one bad battery replaced under warranty one time (the bank was 14 months old, the other battery load tested fine), and it caused the charger to go into full charge mode because the bank wouldn't equalize correctly, and when the engine starter was engaged it blew the tops off of all of the batteries on the bank and scared the daylights out of everyone.

Check the water levels in the cells. From what I've seen, the cells closest to the terminals lose water fastest and when they're low on water they don't hold as good of a charge or as much voltage. Check the water level in all of the cells and add as needed. If they're maintanence free, the battery companies have told me that if you pop the cells open once a year and add water they last a lot longer.