Differences

This shows you the differences between two versions of the page.

--- electrical:severe_battery_use [2018/03/20 13:12]
frater_secessus created
+++ 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.
+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? =====
-The most common low-end targets for [[electrical:12v:lvd|low voltage disconnect]] are:
+For folks willing to trade battery longevity for some amount of increased capacity, common low-end targets for [[electrical:12v:lvd|low voltage disconnect]] are:
+  * 60% DoD / 40% SoC, ~12.0 rested volts
   * 75% DoD / 25% SoC, ~11.7 rested volts
   * 80% DoD / 20% SoC, ~11.6 rested volts
 ===== limiting the damage =====
+  * 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]].
+  * fully charge lead-chemistry batteries as often as possible
+===== 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:
-Deep cycles generally extend the amount of time for a battery to complete Absorption.  Extend the
+  * 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.

RV and vandwellers wiki

User Tools

Site Tools

Differences

Page Tools