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electrical:depth_of_discharge [2023/08/17 21:09] frater_secessus [SoC by voltage] |
electrical:depth_of_discharge [2023/08/17 21:27] frater_secessus [soft and firm charging] |
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So for a 225Ah Trojan T-105 that might be when current acceptance drops to **4.5A at 14.8v**. | So for a 225Ah Trojan T-105 that might be when current acceptance drops to **4.5A at 14.8v**. | ||
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+ | Mythbusting: | ||
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With **lithium batteries** humans might use use amp-counting with [[electrical: | With **lithium batteries** humans might use use amp-counting with [[electrical: | ||
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* at moderate charging rates and voltages between ≥13.4v and <13.8v SoC will be ~100% after some amount of Absorption. | * at moderate charging rates and voltages between ≥13.4v and <13.8v SoC will be ~100% after some amount of Absorption. | ||
+ | ==== soft and firm charging ==== | ||
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+ | Solar is typically a moderate (or " | ||
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+ | So while we can say with confidence that a 100Ah Li battery charged at 20A to 14.0v will be ~100% SoC, the same battery charged to 14.0v at 80A might only be at 75% SoC. And it might get damaginging overcharged if charged to 14.0v very gently at something like 5A.((the BMS cannot detect this scenario)) | ||
+ | The amp counter will probably help here during charging although even it can be thrown off. | ||
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{{ http:// | {{ http:// | ||
- | A rested (no load), fully charged, unFloated lead battery will be 100% around 12.7v-12.8v; | + | A rested (no load), fully charged, unFloated lead battery will be 100% around 12.7v-12.8v; |
The famous chart to the right is used to estimate SoC of a rested battery after a full charge. | The famous chart to the right is used to estimate SoC of a rested battery after a full charge. | ||
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A rested (no load), fully charged, unFloated lithium battery will be 100% around 13.5-13.6v. | A rested (no load), fully charged, unFloated lithium battery will be 100% around 13.5-13.6v. | ||
+ | As we will see below SoC-by-voltage will appear to be **artificially high during charging**((voltage rise)) and **artificially low during discharging**((voltage sag)). | ||
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**Lithium batteries** also exhibit voltage sag under load but typically much less than AGM or especially FLA. An [[electrical: | **Lithium batteries** also exhibit voltage sag under load but typically much less than AGM or especially FLA. An [[electrical: | ||
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+ | ===== estimating SoC while charging ===== | ||
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+ | Similar to voltage sag during discharge, batteries exhibit voltage //surge// or //rise// during charging. | ||
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===== partial state of charge ===== | ===== partial state of charge ===== |