The following measurements apply to 12 Volt batteries, although the
concepts are common to all lead acid batteries.
There are cures for your battery's ailments.
Eight out of ten batteries fail due to sulfation.
Batteries in storage will sulfate at the rate of 1-10% per month
depending on storage conditions
and battery type. Batteries being used will sulfate as well.
Lead sulfate crystals will form on a battery when it is discharging.
MOST of them are returned to the electrolyte as acid when the battery is
recharged.
I say most, because stubborn patches gain a foothold and begin to slowly
grow. Eventually they will electrically short a cell or cover the
plates to the point that the battery does not have sufficient capacity
to function. If growth is severe enough, it will exert physical
pressure and can buckle and break the plates. This is why old battery
cases swell. The swelling is due to unchecked sulfate growth.
Lead sulfates are electrically conductive. BUT, they also act like an
insulator to the chemical reaction with the electrolyte.
There are three methods to eliminate sulfation.
One of them is destructive and kind of iffy
One of them is somewhat messy and hazardous to apply properly but will
recover shorted cell batteries
One of them is totally painless
DESTRUCTIVE: Equalizing Charge
Do NOT use this method on your battery if it is in poor shape.
This is only used on batteries that are functional. It is recommended
that this only be used on batteries that are in storage perhaps once
every 6 months.
If you do this to a severely sulfated battery, it will result in shorted
cells.
An equalizing charge (15V) is applied to the battery for a period
ranging from 10 minutes to 2 hours. You have to monitor the heat
buildup in the battery. The best indication of internal battery
temperature is to feel the positive post. If it feels warm, STOP.
This will get most of the sulfate but will degenerate the soft plate.
If the battery is heavily sulfated chunks of sulfate will fall to the
bottom of the case and result in shorts.
There are great debates within the industry as to how often to use this
method (if at all) owing to it's destructive nature and reduced life
cycle of the battery
I'm sure you will find much discussion on this with a search for
"Equalizing Charge"
MESSY: EDTA treatment
1. Dump the electrolyte into a container.
2. For each cell, in a separate container, add one or two teaspoons of
EDTA with a small amount of warm distilled water.
3. Pour the mixture into the cell and then fill the cell completely
with distilled water.
4. Repeat the steps 2 and 3 until all cells are filled
5. I'd let it sit overnight
6. Dump the mixture
7. Rinse and drain with distilled water
8. Refill with fresh electrolyte
9. Charge the battery up
Here is an article on it
http://www.humboldt1.com/~michael.welch/extras/edta.pdf
PAINLESS: Electronic Pulse Desulfators (pulsers)
Either purchase a commercial unit or build from a schematic or kit an
electronic "Pulse Desulfator" (use that for your search engine). Ebay
seems to have some known as Solargizers that are sold frequently.
Connect it to your battery and then forget it. It Stops further
sulfation from occurring and will begin to recover the battery at the
rate of about 5AH/week (C/20). If the battery is not used on a daily
basis you must attach a trickle charger to it or connect it to a
photovoltaic array.
These units will send a high frequency pulse to the battery. The energy
of the high frequency pulse will dissolve the sulfates and return it as
sulfuric acid to the electrolyte.
The original home built pulser article
http://www.humboldt1.com/~michael.welch/desulfator.pdf
An article on the subject and a bulletin board for homemade units can be
found at this link
http://shaka.com/~kalepa/desulf.htm
If you would like to learn more about lead acid batteries use this link
http://www.windsun.com/Batteries/Battery_FAQ.htm
Be sure to charge the battery for a period of at least 24 hours before
you do any voltage
measurements.
Although a shorted cell is indicated if battery voltage drops below 10.5
(12V), I've restored batteries that initially only measured 3-5 Volts.
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