Please excuse the slight swerve off-topic, but how often should you equalize? I know it's a function of how many charge/discharge cycles. My Magnum 3.1 kw inverter/charger documentation is vague on the issue.
Per the Interstate link above: Equalize every 4 to 8 weeks or when the difference in specific gravity readings vary by 0.020 points or more and always after a normal charge.
The spec sheet for your batteries should specify.
Sulfation and How to Prevent it - Battery University
Interesting battery discussions are here.
I have never been able to bring back any dead or dieing battery.
I often wonder about the effect on my batteries from having three charge sources. I have a three stage battery charger, two 120 amp alternators with Sterling regulators and 450 watts solar with a Morningstar MPPT controller. Here is an example of the charge characteristics of the boat.
Its at the dock fully charged and floating at 13.5v on the charger. I start out a zero dark thirty and the alts and Sterling regulators fire up and drive to 14.5v absorbtion. After a while the Sterling drops it back down to float at 13.5v. I go back to the dock and plug in to shore power and the battery charger drives back to 14.5v absorbtion and then back to 13.5 float. Now sitting at the dock the solar panels and MPPT controller drive the voltage back up to 14.5 absorbtion voltage every morning when the sun is out. In the winter I have seen 15.1v during absorbtion due to the temperature compensation of the controller.
I wonder if driving voltage to absorbtion voltage multiple time impacts the batteries. So far it appears to be OK. I only water once a month and it only requires about 1.5 pints for 8 6v Crown batts. The SGs remain balanced but I only check about every 3 months. Batteries are 32 months old have seen 1200 hrs of engine time. I have only equalized once and think I should add equalizing to our charging scheme. I am hoping to be one of the lucky ones that gets more than 5 or 6 years out of a bank.
I have not had any good results either. Really better off preventing failures than trying to rejuvenate them. I have never had a shorted cell, how old were your batteries for that to happen?
More than 5 years old, and on up to 10 years is the most I can get.
Typically, the shorted batteries I notice they get warmer, and also acid shows up on the outside. These shorts I eventually get are just small drains, and charger is working harder. They are not dramatic massive internal arcing failures.
The article is a good find.Equalizing Charge For Stationary Batteries – Battery University....
Stationary batteries are almost exclusively lead acid and some maintenance is required, one of which is equalizing charge. Applying a periodic equalizing charge brings all cells to similar levels by increasing the voltage to 2.50V/cell, or 10 percent higher than the recommended charge voltage.*...
An equalizing charge is nothing more than a deliberate overcharge to remove sulfate crystals that build up on the plates over time. Left unchecked,*sulfation*can reduce the overall capacity of the battery and render the battery unserviceable in extreme cases. An equalizing charge also reverses*acid stratification, a condition where acid concentration is greater at the bottom of the battery than at the top.
Experts recommend equalizing services once a month to once or twice a year. A better method is to apply a fully saturated charge and then compare the*specific gravity*readings (SG) on the individual cells of a flooded lead acid battery with a hydrometer. Only apply equalization if the SG difference between the cells is 0.030.
During equalizing charge, check the changes in the SG reading every hour and disconnect the charge when the gravity no longer rises. This is the time when no further improvement is possible and a continued charge would have a negative effect on the battery.
The battery must be kept cool and under close observation for unusual heat rise and excessive venting...
Last updated 2016-02-23
The article is a good find.
How many people keep their batteries under constant surveillance during equalization? Those doing it manually may, but many equalizations are regulator programmed with the owner likely absent.
How can SG be regularly checked during the process? Stop the process, wait, test, restart, and repeat? It doesn`t sound practical.
A high charge is applied, usually with pulsation, to force or vibrate sulfur off the plates back into solution, and to mix the solution. That takes some force, I`m not sure batteries were built for those forces.
Under my previous regime of automatic monthly equalization I began to see bits of separator floating loose in the batteries. They were decent LA Marine batts. I suspect,with no certainty, equalization had a hand in their demise. I`m not doing it with the replacements, wondering how it will turn out, an informal test I suppose, in solar maintained batts.
I`m not saying equalization is bad, but it needs to be understood as a relatively violent process batteries were not necessarily designed for, and some discretion exercised.
Is anyone aware of control tests, identical batteries in identical use, one equalized monthly, one not, over an extended period ? We have electrical guys on TF, what do you say?