The 6.4V 6Ah Lead Acid Replacement battery with high discharge capability should satisfy your needs
With high capacity cells and high discharge and pulse capability, the LFP 6-6/9 will most certainly cover most of your needs.
With three forms of built in safety, cell balancing and high quality cells. You are guaranteed reliability and performance when you need it most.
Not recommended for UPS
Electrical Specifications:
Nominal Voltage: 6.8V
Nominal Capacity: 6Ah
Energy: 38.4Wh
Charge Specifications:
Recommended Charge Current: 2A
Maximum Charge Current: 4A
Recommended Charge Voltage: 7.3V
Discharge Specifications:
Maximum Continuous Discharge Current: 9A
Standard Discharging Current: 3A
Discharge Cut-off voltage: 4V
Over Discharge Current: 15A (Limited by PTC)
Dimensions: (L x W x H) : 69mm x 46mm x 98mm (105mm with terminals)