Limitless Lithium Retro Pro 56 Group 24 Lithium Battery

Limitless Lithium Retro Pro 56 is a 12V LifePo4 battery built for high-drain car audio systems, delivering 56Ah of capacity in a compact Group 24 form factor with internal balancing for a streamlined install.

• Voltage: 12V
• Resting Voltage Range: 13.1V–13.4V — open-circuit voltage when the pack is at rest, useful for gauging state of charge before installation or after shutdown.
• Capacity: 56Ah (Not Pb Eq) 200-240 Pb Eq — rated usable capacity in LiFePO4 chemistry with a PbEq comparison used for cross-reference.
• Chemistry: LifePo4 — lithium iron phosphate chemistry chosen for stable discharge characteristics in high-drain applications.
• Operating Temperature Range: -30 to 60 °C / -22 to 140 °F — designed to perform across a wide climate range.
• Weight: 21 lbs
• Dimensions: Height 8.75”, Depth 6.5”, Width 10.125” — fits standard Group 24 mounting footprints.
• BCI Group: Group 24
• Terminal Size: M8x125
• Terminal Orientation: Positive Left
• Life Cycles: 2,000 @ 80% DOD
• Battery Management System (BMS): No
• Balance Board: Yes (Internal)
• Max Charge Voltage: 14.8V
• Max Input Charge Current: 400A
• Continuous Discharge Current: 750A
• Burst Discharge Current: 1200–1300A (Temperature dependent)
• Continuous Wattage Range: 9,000–13,000W (100A–400A Alt)
• Burst Wattage: 16,000W

Designed for premium, high-draw audio systems, the Retro Pro 56 integrates into a Group 24 chassis and supports aggressive peak demands with high burst current ratings. Its internal balance board handles cell balancing within the unit, while the absence of an external BMS means installation must adhere to the specified voltage and current limits. The broad operating temperature range and long cycle life make it well suited to frequent recharge cycles in demanding car audio rigs, with rapid recharging potential thanks to a 14.8V max charge voltage and 400A max input.