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electrical:12v:lvd [2017/05/07 16:59] frater_secessus [common LVD setpoints] |
electrical:12v:lvd [2018/06/23 16:50] frater_secessus [challenges] |
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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 |
- | In most installations | + | The simplest way to implement an LVD is to wire all loads go through |
+ | * a stand-alone LVD with higher current rating (more expensive) | ||
+ | * or run loads off a [[electrical: | ||
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+ | except the [[electrical: | ||
===== common LVD setpoints ===== | ===== common LVD setpoints ===== | ||
- | Lead-acid deep cycle batteries last the longest with best capacity if they are never cycled more than 50% [[electrical: | + | Lead-acid deep cycle batteries last the longest with best capacity if they are never cycled more than 50% [[electrical: |
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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: | [[electrical: | ||
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===== challenges ===== | ===== challenges ===== | ||
- | LVD rely on measured voltage to know when to disconnect, but heavy loads can distort | + | LVD rely on measured voltage to know when to disconnect, but heavy loads can cause distortions (//voltage sag//) in that reading. |
+ | |||
+ | | **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| | ||
+ | |||
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+ | Observe and adjust based on your experience with your own system. |