The populor Lead Acid battery size, customer able to drop in replacement! The dimension is L330×W173×H220 mm 
 
About Rock-12-120 Bluetooth lithium battery
 
The Rock-12-100 lithium battery is safe and reliable whilst being small and lightweight, with a long life and fast charging. Comparing the Rock-12-120 lithium battery with similar batteries, the volume and weight are around a third and a half respectively than that of ordinary lead-acid batteries. The build in battery management system(BMS) provides multiple protection: over-charge, over-discharge, over-current and over temperature. The Rock-12-120 lithium battery will last at least 2000 full cycles before minimal performance changes. This means it can last up to seven years, depending on the frequency of use. It can also be charged and discharged under high current without affecting its expected lifespan. The Rock-12-120 lithium battery can be used with solar inverter, vehicles, electricity grid and many other charging methods. It is very suitable for use in various vehicles, such as electric boats, caravans, RVs and so on.
 
The Rock-12-120 lithium battery support 100A continuously discharge.
Customer can parallel up to 4 of them in parallel, to make a 12v480Ahead system. The maximum continuously discharge rate will be 400A in 4 parallel setups.
Customer can put up to 4 of them in series, to make a 48v120Ah system. The maximum continuously discharge rate will be 100A in 4 setups.
 
Specifications: 
Amp Hours 120.0Ah
Battery Voltage 12V
Operating Temperature Range Charge (-0-50), Discharge (-20 -60)
Nominal Voltage 12.8V
Nominal Capacity 120Ah
Continuously Charge/Discharge Current 100A
Cycle Life  > 2000 Cycles
Maximum Charge Voltage 14.6V
Maximum Discharge Current 100A
Pulse Discharge Current 150A (10S)
Charge Cutt-off Voltage 10V
Weight 12.2kg
Warranty 3 Years 
Certification IEC 62619