Because i use lead acid batteries on my UPS systems, i will be putting all the relevant information that i need on lead acid batteries here
1- What does 74ah (74 amp per hour mean)
In most cases, it means 3.7ah over 20 hours, so you can draw 3.7 amps for 20 hours before the voltage drops to 10.5V, the equation is not linear, so basically you will be able to draw less than 7.4ah in 10 hours (Less than double for half the time), the rating is usually 20 hours on most batteries, the Bosch car batteries (S3 S4 S5…) are measured for 20 hours for example.
The CCA are usually measured for a 10 second period until the voltage drops to 7.5V (Yes, minimum of 7.5V not 10.5)
Now, sometimes, i connect an inverter and a power supply and a battery together, so that the inverter draws from the power supply, while the battery is technically maintaining its charge, if you can’t control the current, and just want the charge to stay put, something between 12.6 and 12.7 is a good voltage, but to be on the safe side, fully charge your battery, then let it sit for 24 hours, then get a voltage reading, tune your power supply to that voltage, and connect them all together.