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--- electrical:severe_battery_use [2019/08/21 22:03]
frater_secessus [Intentionally severe battery use]
+++ electrical:severe_battery_use [2021/05/05 10:55]
frater_secessus [increasing effective Absorption duration] added flloat
@@ Line 1: / Line 1: @@
 ====== Intentionally severe battery use ======
-Lead-acid chemistries prefer light cycling and full recharge between those cycles.  Infrequent excursions below the [[electrical:depth_of_discharge|50% depth of discharge]] norm will not cause much damage assuming a full charge is accomplished ASAP afterwards.
+Lead-acid chemistries prefer light cycling and full recharge between those cycles.  Lead-acid batteries are traditional cycled to [[electrical:depth_of_discharge|50% depth of discharge]] because it offers a balance between duty life (years between failure) and bank size.(("dead lead"))  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 article is about the intentional severe use of lead-acid banks by running them below the 50% mark, **followed by vigorous recharging** at maximal voltage.  This might be desirable when:
+  * reducing the weight impact of lead banks
+  * one wants to make use of old/damaged batteries whose capacity has declined
 ===== how low can we go? =====
@@ Line 17: / Line 20: @@
 ===== limiting the damage =====
-Deep cycles generally extend the amount of time for a battery to complete Absorption.
-  * get power back into the battery ASAP after deep discharge;  drive for alternator charging or run a generator to get bulk stage going
+  * get power back into the battery ASAP after deep discharge;  drive for [[electrical:12v:alternator|alternator charging]] or run a [[electrical:generator|generator]] to get bulk stage going.  Solar alone //might// be sufficient but it might require meaningful [[electrical:solar:overpaneling|overpaneling]].
-  * increase Absorption time, or even set Vfloat == Vabs.
+  * fully charge lead-chemistry batteries as often as possible
-  * if flooded, keep a close watch on water levels
+===== increasing effective Absorption duration =====
+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,((as when the controller setpoint is maxxed out)) you can achieve a similar effect with one or more of these techniques:
+  * if duration setpoint is maxxed then [[electrical:12v:eternal_absorption|set Vfloat == Vabs]].  Absorption duration will effectively be "until the sun goes down".
+  * **charge at a lower current** (charging minimum).  While [[opinion:frater_secessus:charging_faster|overall charging will take about the same amount of time]], Bulk's share of that time will increase and [[electrical:12v:charging#absorption|Absorption will take somewhat less time]].
+  * **Absorb at a higher((but still manufacturer-sanctioned)) voltage** (Vabs), this will decrease Absorption duration.  Keep a close watch on water levels for flooded batts, and also mind the max allowable voltage for AGM/Gel.
+  * **Float at a higher((but still manufacturer-sanctioned)) voltage** (Vfloat).
+  * [[electrical:12v:alt_and_solar|supplement]] solar charging with another charging source during Bulk, allowing more time for solar to finish absorption.

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