| Here is an extract from a posting to boating enthusiats
Lead Acid Battery Defibrillators (raising the dead)
: I am posting this info as it was suggested to me by one of my happy clients that I inform the boating crowd about salvaging, maintaining and extending the life of lead acid batteries. I told him if he was smart he wouldn't tell folks so that he could increase his house battery capacity by salvaging batteries tossed out by his dockside neighbors. I've given him enough time to do so so maybe I can save a landfill or two by passing the information on. I normally deal with folks that maintain Photovoltaic systems with batteries in the 1,000 to 10,000AH range. As you can imagine they have a substantial dollar value invested and seek to extend the life span of their battery bank.
Battery Basics
It is common for lead acid batteries to last 20-70 years with a little help. Most fail within a few years due to a lack of providing what the battery needs (virtually all mechanics and many of the folks that work in the battery trade are unaware of battery dynamics and cures). If you do find a mechanic that understands desulfating pulsers, you've found a state of the art guy. Hang on to him. Battery people won't want to talk about desulfators. The vast majority of battery charging equipment fails to use technology that has been in existence for more than 20 years. How can this be?? Two answers I suppose. The first is consumer education. Now that is the reason for this post. Once informed, many people have a difficult time accepting new things. So lets get on with it shall we?? The leading cause of batt failure (84%) is sulfation. This condition can be corrected with relatively inexpensive electronic desulfators and the use of a trickle charger. When a battery discharges, lead sulfates form on the plates. During recharge MOST (but not all) of the sulfates return to the electrolyte as sulfuric acid (that is why specific gravity is low on a discharged battery). Stubborn patches form and grow with each discharge/charge cycle. Sulfates can also form by the process of self discharge when stored. This condition is aggravated by placing a battery on the ground (where it assumes ground temperature and condenses water out of the air and increases self discharge). The stubborn patches will continue to grow and reduce capacity until they exert enough force to crack a plate and short, rupture the cell interconnects or simply coat the plates with enough sulfate that they cannot chemically function. That is why the cases bulge on old batteries. This is why you buy a 300CCA battery to spin the 100A starter in your car. If you bought a 100CCA battery you would be in trouble in a month or so. Sulfation is graded in three classes of bonding strength. If a battery does not get rid of a grade sulfate the grade increases to the next tougher level in a short time. A class I bonded sulfate is removed by recharging your battery after discharge (most anyway). Class 1 bonded sulfates that are not reconstituted back into the electrolyte as sulfuric acid will soon convert to a Class II bond. Class II bonded sulfates can be removed (most) by using an equalizing charge (15V for a 12V battery). This occurs at the expense of premature aging of the positive plate from the excessive charging voltage. Class II bonded sulfates can be rapidly removed by electronic pulse techniques (totally). Class II boded sulfates that are not reconstituted as sulfuric acid will soon convert to a Class III bond. Class III bonded sulfates will not respond to equalizing charges. These are the large crystal growths that normally choke the life out of a lead acid battery. Electronic pulse techniques will SLOWLY reconstitute these crystals back into sulfuric acid. There may be those that swear by the equalizing charge. It does work if you use it each time you discharge your batteries. It will wear out your batteries faster also. What is a desulfating pulse?? A pulse that can peak in 1/10th of a millionth of a second. Like lightening finding a favorable path to ground, a desulfating pulse finds it's way to sulfate crystals. After that time period, any energy expended mostly goes to waste as the chemical reaction starts and the energy is absorbed into the clean plate areas of the cell. Don't attempt to use a high frequency generator as the battery needs a bit of time to reset itself in order for the next pulse to work. Commercial pulsers are available but expensive. It appears that our homemade units can put out 4 times the pulse energy. If you care to learn more about the subject, I invite you to visit the website where much more detail is available along with schematics for DIY's. Parts kits and assembled pulsers are available for those lacking the skills or equipment to assemble and test them. http://www.shaka.com/~kalepa/desulf.htm You can also do an internet search for "lead acid battery pulse"
By the way if you want to kill a battery quickly, use tap or well water.
It will cause the formation of calcium sulfates on the plates. There is no known cure for this condition.
Another life shortening trick is to use a battery transport device that grips the battery by the posts.
It can rupture the post seal the first time you use it and thereafter acid will wick over the top and increase self-discharge. The posts are large in order to accommodate large electrical fittings not as lift points. They do make battery transport devices that lift by the exterior case. Another little known fact. You do not need an expensive charger for your batteries if they are protected with a desulfating pulser. A trickle charger is adequate to meet the needs of the flooded lead acid batt. Unless you stay onboard and run heavy 12V loads (lots of lights, 12V refrigerator, etc...) The more exotic AC dockside power chargers contain a lot of electronics devoted to running a battery through an antiquated (pre-pulse technology) 2 to 4 step charging regimen. Basically the steps insure safe, rapid charging and may include a destructive equalizing phase. Most folks I know do not need the rapid charge capability. They dock the boat and apply shore power and the boat sits until the next cruise. The trickle chargers will bring batts up overnight. Equalizing charging is a crude attempt to "equalize" the individual cell voltage. Cells get unequal due to sulfation. A desulfator will "equalize" the cells. Another use of the equalizing charge is to stir the electrolyte in order to avoid electrolyte stratification (the acid concentrating at the bottom of the case). Stratification is eliminated IF the desulfator provides enough pulse amps. While we are on the subject of do's and don'ts, DO yourself a favor and DONT invest in starved electrolyte batteries (the kind that do not slosh when you shake them) (sometimes referred to as SLA (sealed lead acid) or VRLA (valve regulated lead acid)) They will dry out in 3-5 years as they are cycled (discharged/charged) and there is no current treatment that will reinvigorate them. They are great for manufacturers, wholesalers, retailers and use in outer space (zero gravity environments). They can be shipped easily as there is no acid spill if inverted or the case is cracked. They have a long shelf life as they are not as prone to self discharge sulfation with the reduced acid content. The dehydration syndrome happens to coincide with max life expectancy of a flooded cell batt that does not have desulfator protection. So they are consumer acceptable. Unfortunately their life expectancy pales in comparison to what is possible with a flooded cell batt.
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