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electrical:depth_of_discharge [2020/06/10 13:01] frater_secessus [SoC by specific gravity] |
electrical:depth_of_discharge [2023/05/29 12:00] frater_secessus [SoC by voltage] |
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DoD has a **significant impact on longevity of deep cycle batteries**. | DoD has a **significant impact on longevity of deep cycle batteries**. | ||
- | ===== 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)) | + | Note: This information is primarily relevant to lead-chemistry batteries. |
+ | ===== effect of DoD on battery life ===== | ||
+ | |||
+ | How deeply one regularly | ||
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| | | | | | | | | | | | | | | | | | | | | | ||
- | | **DoD**| | + | | **DoD**| |
| 10| 90| 22.5| | | | | | | | | 10| 90| 22.5| | | | | | | | ||
| 20| 80| 45| 3000| 135| $1.93| | | 20| 80| 45| 3000| 135| $1.93| | ||
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- | ===== SoC by amps ===== | + | ===== estimatating SoC ===== |
+ | |||
+ | ==== SoC by specific gravity | ||
+ | |||
+ | > "The truest measure of a [lead chemistry] battery' | ||
+ | |||
+ | Only flooded-type batteries are practical for SoC assessment by SG of the electrolyte. | ||
+ | |||
+ | * temperature of the battery | ||
+ | * SG chart from the battery manufacuturer | ||
+ | * [[https:// | ||
+ | |||
+ | |||
+ | |||
+ | ==== SoC by amps ==== | ||
A [[electrical: | A [[electrical: | ||
+ | Note that deep cycle battery [[electrical: | ||
- | ===== SoC by voltage ===== | + | |
+ | ==== SoC by voltage ==== | ||
+ | |||
+ | Note: read [[https:// | ||
100% SoC (~12.7v) is measured [[electrical: | 100% SoC (~12.7v) is measured [[electrical: | ||
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* intermittent heavier loads that leave the system with measured >=12.2v when that load is removed | * intermittent heavier loads that leave the system with measured >=12.2v when that load is removed | ||
- | ===== SoC by specific gravity ===== | + | The more challenging task is judging when to kill the circuit based on voltage **under heavier loads**. Consider this chart: |
- | > "The truest measure of a battery' | + | {{ https://i.stack.imgur.com/bm93G.jpg}} |
- | Only flooded-type batteries are practical SoC assessment by SG of the electrolyte. | + | For a 200A bank 50% DoD would be 12.1v at rest, ~12.0v at C/10 (20A discharge), ~11.55v at C/5 (40A discharge), and 11.2v at C/3 (~70A discharge). |
- | * temperature of the battery | + | It may take experimentation with your system to see where the battery |
- | * SG chart from the battery manufacuturer | + | |
- | * [[https:// | + | |
+ | - apply expected load | ||
+ | - run battery down to 11.5v (then 11.25, 11, 10.75, 10.5 etc until battery no longer rebounds to 12.1-12.2v) | ||
+ | - remove load | ||
+ | - observe battery voltage | ||
+ | If the battery rebounds to the desired voltage then repeat to deeper discharge. | ||
+ | An [[electrical: | ||