User Manual

RS02109/0814/CD 22 www.cdtechno.com
Liberty DCS cells are specif ically designed for cycle service and while their r obust design allows them to be
used in numerous types of cycle applications from mild shallow DoD service t o continuous PSoC service,
battery service life can be maximized by following recommended cycle charge voltages and currents as shown
in Table 1 (Section 7.1). In addition, f ollowing recommended equalization charging procedures, temperature
compensation guidelines and maintaining accurate SoC and DoD limitations will ensure the Liberty DCS cells
provide long and reliable cycle service.
CAUTION:
RECHARGE BATTERIES AS SOON AS POSSIBLE AFTER
AN EMERG ENCY DISCHARGE. Failure to recharge batteries
immediately after emergency discharge may lead to sulfation,
or in the case of deep discharge, a complete battery fai l ure
due to hydrati on. If recharging at freshening/equalize voltage
is impractical, promptly recharge at float voltage.
10.3 Low Floa t Volta ge a nd S ulfation
Either because of incorrect charger voltage adjustment, excessive intermittent or static loads paralleling
the charging source, low operating temperature or simply not fully recharged; a battery may not receive
adequate charging voltage. In some cas es, th e charg er may ev en be tur ned off , err oneo usl y or by
ch oice. The net r esu lt is a batt ery l eft in a parti ally d isch arge d or und erch arg ed cond iti on. Th e first
observable sig ns ma y be err atic cel l voltages. Althoug h not v isible t o t he observer, the plates will
become sulfated.
If you suspect sulfated plates, contact the C&D Technical Services Department 1-800-543-8630 or
([phone] for assistance. Sulfated batteries are not fully charged batt er ie s thus have not
completed the electrochemical react io n of recharge. Accordingly, they will have reduced capability. If
allowed to remain in a partially charged condition for an e xte n ded pe r iod of t im e, su lf at e d bat t er ies m a y
suffer irreversib le damage, requiring replacement.
10.4 Hydration
A bat t er y t ha t has been severely over-discharged and left in a discharged condition without immediate
recharge is subject to damage known as hydration. This is a phenomenon in which the electrolyte specific
gravity has been reduced to a value so low it permits the lead components to dissolve into the
electrolyte.
The reaction of dissolution f orm s many compounds and salts, gener ically refer red t o as hydrate.
On recharg e these compounds r eact to clog separat or pores and form metallic lead. As time passes
thousands of short circuit paths are created in the separat ors placed between the positive and negative plates
to provide electrical insulation. Very often, the ef fect of thes e short cir cuits goes unn ot iced e xcept f or a
slight increase in charging current. As the reaction continues, however, short circuits become so extensive it is
almost impossible to keep the cells charg ed. Finally, the cells experience total failure. Liberty 2V batteries
are more res istant t o hydration t han t ypical wet cel ls, larg ely beca use of the th ick absorb ent gl ass mat
sep arator bet ween th e plate s. Ho wever, in severe cases of hydration, internal short circuits can form.