EFFECTS OF FAST CHARGING ON HYBRID LEAD/ACID BATTERY TEMPERATURE

The effects of very fast charging on two types of deep-cycling hybrid lead/acid batteries were determined using a MINITCHARGER(TM) to control the charging current. One of the hybrid batteries was flooded and contained Pb-4.7wt.%Sb positive grids, the other was a valve-regulated battery with Pb-1.5wt.%Sb-0.3wt.%Sn positive grids. Results are presented and discussed in relation to these battery types, but many of the conclusions are more generally applicable. It was found that both 5-min/50%-recharge and 15-min/80%-recharge rates could be achieved, in the case of the flooded battery, with a quite acceptable temperature increase. Following an 80% depth-of-discharge, the dominant source of heat was ohmic during the first 40% of the charge returned at very high rates. The temperatures were distributed non-uniformly within the battery. After this, non-ohmic polarization became progressively more important. For the hybrid recombination battery, the oxygen cycle is a substantial source of heat during the latter stages of the charge, particularly in comparison with previous non-antimonial batteries that have been investigated.