Your RV lead-Acid battery is a consumable item. No matter how well you care for it, if you use it as intended, sooner or later it will need to be replaced. The difference between replacing it sooner or later is understanding the charge cycle.
Lets start with an understanding that a battery doesn’t make electricity it stores it. When the electricity is used the battery must be recharged. A battery “cycle” is one discharge and recharge.
Battery life is directly related to how deep the battery is cycled each time. A deep cycle is considered to be discharging the battery from 100% to 20%, and then charging back up to 100%. However, a battery that is never discharged below 50% each cycle will last about twice as long as one that was deep cycled each time. Conversely, discharging the battery to 0% or 10.5 volts will greatly decrease the lifespan of the battery.
The accompanying chart lists voltages as related to percent of discharge when the battery is under light load. The chart indicates 50% is the lowest a battery should be discharged for battery longevity however a few experts say 40% is okay. Regardless, avoid discharging the battery below the 40% level whenever possible.
Extend your RV’s lead-acid battery life by fully recharging as soon after a discharge as possible and avoiding deep discharges when possible.