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electrical:depth_of_discharge [2020/11/26 10:17] frater_secessus [SoC by voltage] |
electrical:depth_of_discharge [2023/08/17 17:30] frater_secessus [Depth of discharge / State of Charge] |
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For solar powered systems the greatest DoD (and therefore lowest SoC) will be in early morning just before the panels start creating power again. | For solar powered systems the greatest DoD (and therefore lowest SoC) will be in early morning just before the panels start creating power again. | ||
- | DoD has a **significant impact on longevity of deep cycle batteries**. | + | DoD has a **significant impact on longevity of lead deep cycle batteries**.((and, to a lesser degree, lithium batteries)) |
- | ===== effect of SoC on battery life ===== | + | |
+ | Note: This information is primarily relevant to lead-chemistry batteries. | ||
+ | ===== effect of DoD on battery life ===== | ||
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)) | 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)) | ||
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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 | ||
- | The more challenging task is judging when to kill the circuit based on voltage **under heavier loads**. | + | The more challenging task is judging when to kill the circuit based on voltage **under heavier loads**. |
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+ | {{ https:// | ||
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+ | 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). | ||
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+ | It may take experimentation with your system to see where the battery voltage rebounds after removing the heavy loads. | ||
- apply expected load | - apply expected load | ||
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If the battery rebounds to the desired voltage then repeat to deeper discharge. | If the battery rebounds to the desired voltage then repeat to deeper discharge. | ||
+ | An [[electrical: | ||
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This section [[electrical: | This section [[electrical: | ||
+ | ===== lithium SoC ===== | ||
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+ | Lithium chemistries have very flat voltage curves, making it notoriously difficult to gauge SoC by voltage. |