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electrical:12v:lvd [2020/11/20 16:15] frater_secessus [Low Voltage Disconnect (LVD)] |
electrical:12v:lvd [2023/09/06 10:53] frater_secessus [Low Voltage Disconnect (LVD)] |
A low voltage disconnect is used to stop loads from dragging a battery bank below a given voltage (Vlvd). | A low voltage disconnect is used to stop loads from dragging a battery bank below a given voltage (Vlvd). |
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The simplest way to implement an LVD is to wire all loads go through the LOAD output of the charge controller, and set the controller's Vlvd. If the load is heavier than the LOAD output can provide, you can run loads off a [[electrical:12v:relay|relay]] triggered by the LVD. | |
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| ===== examples ===== |
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If the controller has no LVD (ie, no LOAD output) you can use a [[https://amzn.to/3m2OTp3|stand-alone LVD]] powered by the battery. | [[https://amzn.to/3Ri94RY|{{ https://m.media-amazon.com/images/I/51ODnDvz-rL._AC_UL400_.jpg?125}}]] |
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| * [[https://amzn.to/3Ri94RY|Victron Battery Protect]] |
| * [[https://amzn.to/47Xzz5n|Blue Sea 7635 m-LVD]] |
| * [[https://www.amazon.com/s?k=low+voltage+disconnect&link_code=qs&tag=themousepad|various amazon listings]] |
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| One can also **DIY a low voltage disconnect**. |
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| In theory the simplest way to implement an LVD would be to wire all loads go through the [[electrical:solar:charge_controller#using_load_output|LOAD output]] of the charge controller, and set the controller's [[electrical:solar:charge_controller_setpoints|Vlvd]]. In practice this is rarely done for reasons given in the link above. It is more common to run a [[electrical:12v:relay|relay]] on the LOAD output, which is triggered ON/OFF by the LVD setting: |
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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 [[https://amzn.to/3m2OTp3|stand-alone LVD]] powered by the battery. |
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except the [[electrical:inverter|inverter]], due to the heavy current draw. The inverter will have its own internal LVD. | |
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[electrical:12v:deep_cycle_battery#lithium_chemistries[electrical:12v:lifepo4_batteries_thread|LiFePO4]] nominal 12v banks can be safely drained to 80-90% Depth of Discharge. That point is something like 12.0v.((http://rvwiki.mousetrap.net/doku.php?id=electrical:12v:lifepo4_batteries_thread#notable_voltage_reference_points)) | [[electrical:12v:deep_cycle_battery#lithium_chemistries[electrical:12v:lifepo4_batteries_thread|LiFePO4]] nominal 12v banks can be safely drained to 80-90% Depth of Discharge. That point is something like 12.0v.((http://rvwiki.mousetrap.net/doku.php?id=electrical:12v:lifepo4_batteries_thread#notable_voltage_reference_points)) |
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===== challenges ===== | ===== challenges ===== |