As an FYI, you can use the battery capacity vs discharge rate chart "as a percent" to calculate the actual capacity of your battery's amp hour ratiing.
For example if your battery has 75 AH, use that as 100% in the chart.
At 12.5 amps of continuous discharge, for example, a fully charged 75 AH battery will last 70% of its 20 hour rating at 5 amps (or 14 hours).
This is why folks add multiple 12 volt batteries so in a 2 battery "bank" each (correctly wired) battery will see only 1/2 of the total system demand therby extending the useful life of the bank in addition to the "doubling" of rated capacity.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW