Those 16” fans draw 42 Amps each at 12 volts. What size relay are you using. If you are using a thermostat than your lower hose temperature should be equal to or less than the stat rating.
The Anti Gravity batteries have a nice feature in their BMS. If the battery is dead you can push a button and it will give you one more start. Don’t forget that you will need a different battery charger with lithium.