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electrical:12v:battery_monitor [2024/02/11 15:13] frater_secessus [how they work] |
electrical:12v:battery_monitor [2024/03/06 17:44] frater_secessus [inexpensive shunts] |
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Heads up: there are // | Heads up: there are // | ||
+ | |||
+ | ===== sizing ===== | ||
+ | |||
+ | The shunt should be sized to handle your highest expected demand comfortably. For example, a system designed for 80A of current would require a 100A shunt. | ||
===== how they work ===== | ===== how they work ===== | ||
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===== drift and reset ===== | ===== drift and reset ===== | ||
- | Small acccounting errors accumulate | + | Small problems accrue |
- | * counting is inaccurate because current is very low (<1A) or very high (the monitor' | + | * the **measurement can be inaccurate** because current is very high or low relative to the shunt' |
- | * counting is accurate | + | * the measurement and counting is **accurate but is not reliable for estimating changes in state of charge**. This isn't a significant issue with lithium, but lead chemistries have substantial charging inefficiencies((10-20% in Absorption and 100% in Float since that stage is just offsetting self-discharge)) and consume |
* or a combination of the above | * or a combination of the above | ||
- | For those reasons the monitor | + | For those reasons |
+ | |||
+ | - automatically by the monitor when a certain voltage setpoint is achieved.((14.0v = 100%, for example)) | ||
+ | - manually by the user. For practical reasons | ||
One rule of thumb is to reset the monitor 1x/ | One rule of thumb is to reset the monitor 1x/ | ||
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[[https:// | [[https:// | ||
- | The 500A SmartShunt is available in [[https:// | + | The 500A SmartShunt is available in [[https:// |
Both setups can provide voltage, current, and temperature information to the app or directly to other Victron gear like solar charge controllers.((the Orion-TR is a notable and much-lamented exception)) | Both setups can provide voltage, current, and temperature information to the app or directly to other Victron gear like solar charge controllers.((the Orion-TR is a notable and much-lamented exception)) | ||
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By default the backlight is ON when discharging and FLASHING((slow pulsing)) when charging. | By default the backlight is ON when discharging and FLASHING((slow pulsing)) when charging. | ||
+ | |||
+ | == quirks == | ||
+ | |||
+ | The decimal point is small and moves as numbers increase. | ||
+ | |||
+ | |||
+ | * 1**.**234A (also 0.123A) | ||
+ | * 12**.**34A | ||
+ | * 123**.**4A | ||
=== Renogy === | === Renogy === | ||
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=== other examples === | === other examples === | ||
- | [[https:// | + | [[https:// |
Heavier-duty shunts are available (up to [[https:// | Heavier-duty shunts are available (up to [[https:// |