User Manual

RS02109/0814/CD 23 www.cdtechno.com
10.5 Open Circuit – Late Installations
As s oon as a bat ter y is dis conne ct ed from a charger, loca l act ion (self-discharge) b egins. This is c aused b y
inhere nt internal losses within the cell. In the case of Liberty 2V cel ls , a s e lf-dis c harge is expect ed to occur at
a rate of “up to 3.0 percent” of full charge per month at 77°F (25°C). Therefore, if cells remain, for whatever
reason, on open circuit (with no charg e supplied) for prolonged periods of time, the affected cells may become
sulfated and require corrective action in the form of a freshening charge, see Sections 5.2, 7.1 & 7.2.
10.6 Parallel Battery Strings
When s tr ings of batteries of equal voltage are connected in parallel, the overall capacity is equal to the sum
of t he c apac i t ies of the ind i vid u al s tr i ngs . When p ar al le li ng va l ve-r egul ated b att eri es is nece ssar y, the
external circuit resistance should be matched for each battery. A wide variation in battery circuit resistance can
result in unbalanced discharge (i.e., excessive discharge currents in some batteries and less discharge in
others). As a consequence, cell failures in one battery string and the subsequent loss of perf ormance
capacities of that str ing wil l res ult i n high er lo ads in th e lower resis tanc e inter c onnect io ns of some parallel
strings that may exceed the ratings of the battery interconnect ions and/ or cables. C&D recomm en ds
paralleling str ings t o obtain higher capacity, to increase system reliability and with properly installed
disconnects, perform maintenance on one string at a time.
10.7 High Temperature Operation
Operating a battery at temperatures exceeding 77°F (25°C) will reduce the battery life.
Elevated temperatures accelerate the electrochemical r eact i on wit h in t he le a d ac i d bat t er y.
For additional information, refer back to Section 8.4.