Lead-acid chemistries prefer light cycling and full recharge between those cycles. Lead-acid batteries are traditional cycled to 50% depth of discharge because it offers a balance between duty life (years between failure) and bank size.1) Pulling the bank below 50% DoD in emergnecies will not automatically cause damage assuming a full charge is accomplished ASAP.
This article is about the intentional and chronic depletion of lead-acid banks below the 50% mark, followed by vigorous recharging. This might be desirable when:
For folks willing to trade battery longevity for some amount of increased capacity, common low-end targets for low voltage disconnect are:
Deep cycling generally extends the amount of time for a battery to complete Absorption. At some you may run into the controller's maximum Absorption duration. While you may not be able to increase the actual duration,2) you can achieve a similar effect with one or more of these techniques: