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--- electrical:depth_of_discharge [2020/06/10 13:00]
frater_secessus [SoC by voltage]
+++ electrical:depth_of_discharge [2020/06/23 10:55]
frater_secessus
@@ Line 8: / Line 8: @@
 ===== effect of SoC on battery life =====
-How deeply one discharges lead-chemistry batteries will have a **direct effect on how long the battery bank will last**.((Banks are typically replaced when they have lost 20% of their capacity))
+How deeply one regularly discharges lead-chemistry batteries will have a **direct effect on how long the battery bank will last**.((Banks are typically replaced when they have lost 20% of their capacity))
@@ Line 36: / Line 36: @@
-===== SoC by amps =====
+===== estimatating SoC =====
+==== SoC by specific gravity ====
+> "The truest measure of a [lead chemistry] battery's state of charge is the specific gravity of the battery acid." -- Rolls battery.((http://support.rollsbattery.com/support/solutions/articles/428-state-of-charge-charging-flooded-lead-acid-batteries))
+Only flooded-type batteries are practical for SoC assessment by SG of the electrolyte.  Needed for this operation:
+  * temperature of the battery
+  * SG chart from the battery manufacuturer
+  * [[https://amzn.to/3dOHGEU|battery SG tester (hydrometer)]]
+==== SoC by amps ====
 A [[electrical:12v:battery_monitor|battery monitor]], usually a amp/coulumb counter with a shunt, will measure the current going to/from the battery.  It will often show real-time current flow and a state of charge percentage.  It may also show voltage (see below).
+Note that deep cycle battery [[electrical:12v:battery_capacity|capacities]] are given at the "20 hour rate", roughly depleting the battery over the course of a day/night cycle. Heavier loads will cause apparent capacity to decrease.  Lithium is much less susceptible and tends to deliver more predictable capacity.
-===== SoC by voltage =====
+==== SoC by voltage ====
 % SoC (~12.7v) is measured [[electrical:12v:charging|after the bank has been fully charged]] and then rested. It is measured "on the way down";  measuring "on the way up" while charging will lead to false confidence and leaving the battery [[electrical:12v:psoc|less than fully charged]].
@@ Line 55: / Line 71: @@
   * constant light loads with measured >=12.2v
   * intermittent heavier loads that leave the system with measured >=12.2v when that load is removed
-===== SoC by specific gravity =====
-> "The truest measure of a battery's state of charge is the specific gravity of the battery acid." -- Rolls battery.((http://support.rollsbattery.com/support/solutions/articles/428-state-of-charge-charging-flooded-lead-acid-batteries))
-Only flooded-type batteries are practical SoC assessment by SG of the electrolyte.  Needed for this operation:
-  * temperature of the battery
-  * SG chart from the battery manufacuturer
-  * [[https://amzn.to/3dOHGEU|battery SG tester (//hydrometer//)]]

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