The use of carbonaceous materials in lead-acid batteries (LABs) has led to advancements in lead-carbon batteries (LCBs). However, despite their performance benefits, challenges remain, including the hydrogen evolution reaction (HER) and poor compatibility between carbon and lead. To address these issues, we successfully developed lead-carbon composites with a highly conductive Pb-C interface. These composites were incorporated into laboratory-made LABs, where the battery capacity remained stable for over 240 cycles during constant power discharge (approximately 6C to 8C), with a 0.15C charge to compensate for the energy lost during cycling. In contrast, the capacity of the commercial LAB without composites declined after 20 cycles. Furthermore, the composites were incorporated into laboratory-fabricated LAB systems for PV energy storage and evaluated against a commercial battery system with the same capacity and voltage. The experimental results revealed that the discharge power remained stable, whereas the commercial battery system exhibited a decline under identical PV conditions after three months.