Here's some info I copied just this morning:
Re: Equalizing Battery
Posted by: "Henry"
lhejre@foographics.com oldmanxx2002
Here's mine from my web site which was provided to me by Max Pille in
1995 who was a well known from his activities at FMCA and other places
as a part of his emplyment for an inverter company.
____________ _________ _________ _________ _________ _________ _
Equalizing or conditioning batteries refers to a method of charging
deep cycle wet cell batteries which is intended to restore battery
capacity, revive battery efficiency, and extend battery life. The
process involves periodically applying a controlled overcharge cycle to
batteries. This type of charge cycle requires that certain procedures
and precautions be followed.
WHY EQUALIZE BATTERIES
While a battery is being discharged, sulfuric acid in the electrolyte
reacts with the lead plates in a chemical reaction, which produces
electricity and lead sulfate. When the battery is re-charged,
electricity flows back into the battery and causes a reverse chemical
reaction, which turns the lead sulfate back into lead and sulfuric acid.
However, with each discharge and recharge cycle, a small amount of lead
sulfate will remain on the plates. Using a three stage charger will
minimize the amount of residual sulfate left on the plates but some
will still accumulate with each discharge and recharge cycle.
If this sulfate is left in place for very long, it will harden or
crystallize and eventually reduce the batteries capacity, increase its
internal resistance and destroy the batteries ability to produce an
adequate amount of power. When this occurs, even an equalize charge can
not remove the sulfate and the battery becomes useless except as an
item to be recycled to reclaim the lead and prevent contamination of
the environment.
Also, over time, the electrolyte tends to stratify into layers of acid
and water with higher concentrations of acid near the bottom of each
cell and more diluted electrolyte near the top. This causes uneven
specific gravity within a cell further reducing its capacity and
efficiency.
THE EQUALIZING PROCESS
An equalizing charge is a controlled overcharging cycle, which performs
several actions within the battery and provides certain benefits.
During equalize, the voltage is raised to approximately 2.7 volts per
cell, or about 16.2 volts for a 12 volt battery. The current output of
the charger should be limited to about 5% of the battery's capacity. In
other words, a 200 amp hour battery should be allowed to accept no more
than about 10 amps of current. This will help prevent overheating. The
equalize cycle is timed to be between 4 and 8 hours depending on the
features of the charging source, but the cycle can always be terminated
early if necessary. The particular battery manufacturer' s
recommendations for equalization time should be followed.
This elevated voltage results in a vigorous charging action to take
place within each cell, which has several effects on the battery. First,
much of the residual sulfate is forced to re-combine with the
electrolyte in the form of sulfuric acid. Crystallized sulfate, which
will not re-combine is broken loose from the plates and falls
harmlessly to the bottom of the battery. Deep cycle batteries have
additional space beneath the plates intended to collect this material.
This action cleans the plates exposing fresh lead to the electrolyte
and restores battery capacity.
The vigorous bubbling action, which occurs during, equalize stirs up the
electrolyte and restores it to a consistent mixture of acid and water.
The equalizing process also causes all cells in a battery to reach
their maximum idle potential of 2.1 volts.
WHEN TO EQUALIZE
It is best to check with the battery manufacturer' s recommendations
before equalizing since each manufacturer has slightly different
suggestions on how often and how long to equalize their batteries. But,
as a general rule, it is a good practice to equalize batteries after
every 10 or 12 deep discharges and re-charge cycles. For batteries in
constant discharge and recharge usage, this would mean about every two
weeks. For periodic users, it would mean about two or three times a
year. For seasonal users, this could mean at the beginning and end of
the season. When using a battery monitor such as a Link 2000,
equalizing should be done when you notice the Charge Efficiency Factor
(CEF) begin to drop.
HOW TO EQUALIZE
Again, check with the battery manufacturer' s recommendations, but as a
general rule, the following steps should be observed:
1. Only attempt to equalize wet cell deep cycle batteries. Never
equalize gel batteries or maintenance free batteries.
2. The batteries should be fully charged and near ambient temperature
before beginning an equalize charging cycle.
3. There should be a sufficient amount of electrolyte in each cell to
cover the plates, but do not top-off each cell until after equalizing.
Since there is some heating of the cells during equalize, the
electrolyte will expand and could overflow the cells if they were
topped-off before equalizing. This would not only make a mess, but
force you to terminate the equalize cycle too early to gain maximum
benefit and would result in diluted electrolyte when it came time to
add water.
4. Leave the caps on each cell. The caps are vented, and when left in
place will prevent splattering of electrolyte onto the top of the
battery when the bubbles pop. It is a good idea to lay a paper towel
over the caps. This makes it easy to spot a cell that may start
spitting electrolyte, and will soak up the liquid when this does happen.
5. Since the batteries will give off significant quantities of
explosive hydrogen and oxygen gas during equalize, plus produce
moisture, which will contain some amount of corrosive sulfuric acid, it
is imperative that sufficient ventilation be provided. Avoid smoking or
generating any sparks or flame near the batteries during this charge
cycle.
6. All DC loads on the batteries should be turned OFF and disconnected.
Since the battery voltage will be higher then normal during this charge
cycle, some DC equipment could be damaged if left ON. Also these loads
would draw current from the charger which should be available to the
battery instead.
7. Equalize only one bank of batteries at a time.
8. With older Freedom inverter/chargers, to limit the charging current
to less than 15 amps DC, set the power-sharing feature of the charger
to 5 amps AC using the remote control panel. Newer versions
automatically set a special equalize current limit during the equalize
cycle.
9. During the equalize cycle, periodically check the batteries for any
spitting cells and if this begins to happen, terminate the equalize
cycle early. Do not start an equalize cycle and then leave the
batteries unattended.
10. After equalizing, turn OFF the charging source, and allow the
batteries to cool to ambient temperature before resuming normal float
charging. After the batteries cool is a good time to check the specific
gravity in each cell. They should all be 1.265 +/- .050 at 80 degrees F.
11. Refill each cell with distilled water up to the FULL indicator.
START/STOP EQUALIZE CHARGE CYCLE
1. When using the standard Freedom remote control panel, an equalize
charge cycle is started by turning dip switch #1 ON for one second and
then back OFF again. This will start an 8 hour equalize cycle. After
the cycle times out, the charger will go to float mode. To terminate
the cycle early or to allow the battery to cool down after equalize, AC
input power to the charger should be interrupted. When AC power is re-
applied to the charger, it will resume normal charging.
2. When using the Link 2000 remote control panel, the equalize charge
cycle is started by first turning ON the charger and waiting until it
goes into the float mode. Then press the SETUP button and hold it until
it begins to flash. Then release the SETUP button and immediately press
both the VOLTS and A hrs buttons simultaneously and hold for five
seconds until the red CHARGE LED begins to flash and the "E" in the
display goes out. To terminate the equalize cycle and force the charger
into the float mode, repeat the same setup procedure. The cycle will
automatically terminate after 8 hours or if AC input power to the
charger is interrupted.
3. When using the Link 2000R to control equalizing using the Freedom
charger, it will operate the same as the Link 2000 described above. If
the alternator is the charging source, some differences will be
apparent. The procedure for start/stop equalize is the same, but the
control of the charging source (alternator) is different. The cycle is
3.5 hours long, and the charge current is limited to 4% of battery
capacity up to 16 amps maximum.
ADDITIONAL PRECAUTIONS
If some cells in a battery begin spitting electrolyte during equalize
and continue spitting long after the charger has been turned OFF, this
indicates that the spitting battery may have a shorted cell. If this
happens, disconnect any batteries which are in parallel with the
questionable battery as these batteries will continue to supply current
to the questionable battery and cause it to get very hot. When things
cool down, check the suspect battery with a hydrometer. A shorted cell
will read much lower than the others. If this is the case, the battery
must be replaced. Batteries which are likely to develop a shorted cell
are more likely to do so during an equalize cycle since the battery is
being subjected to more thermal stress during this type of charge then
it is accustomed to. Chances are the battery would have developed the
shorted cell sooner or later anyway, but its better to find this out
when the batteries are being closely monitored as during an equalize
cycle.
Whenever working with batteries, always wear protective clothing and
eye protection. Avoid generating sparks, open flame, or smoking near
batteries.