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electrical:12v:lvd [2017/05/07 16:29] frater_secessus [Low Voltage Disconnect (LVD)] |
electrical:12v:lvd [2021/10/04 12:30] frater_secessus [Low Voltage Disconnect (LVD)] |
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====== Low Voltage Disconnect (LVD) ====== | ====== Low Voltage Disconnect (LVD) ====== | ||
- | A low voltage disconnect is used to stop loads from dragging a battery bank below a given voltage. | + | A low voltage disconnect is used to stop loads from dragging a battery bank below a given voltage |
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+ | In theory the simplest way to implement an LVD would be to wire all loads go through the [[electrical: | ||
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+ | controller LOAD output -> relay -> loads((the LOAD triggers the relay, but actual power comes from the battery bank)) | ||
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+ | If the controller has no LVD (or not no LOAD output at all) you can use a | ||
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- | In most installations all loads go through the LVD except the inverter, due to the heavy current draw. The inverter will have its own internal LVD. | ||
===== common LVD setpoints ===== | ===== common LVD setpoints ===== | ||
- | Lead-acid deep cycle batteries | + | Lead-acid deep cycle batteries are typically discharged |
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+ | This following chart((http:// | ||
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+ | {{ : | ||
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+ | The sweet spot appears to be 40% DoD based on the graph. | ||
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+ | [[electrical: | ||
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+ | ===== challenges ===== | ||
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+ | LVD rely on measured voltage to know when to disconnect, but heavy loads can cause distortions (//voltage sag//) in that reading. | ||
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+ | | **State of Charge**| | ||
+ | | 100| 12.70| | ||
+ | | 90| 12.60| | ||
+ | | 80| 12.40| | ||
+ | | 70| 12.30| | ||
+ | | 60| 12.20| | ||
+ | | 50| 12.10| | ||
+ | | 40| 12.00| | ||
+ | | 30| 11.80| | ||
+ | | 20| 11.65| | ||
- | [[electrical: | ||
+ | Observe and adjust based on your experience with your own system. | ||