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electrical:12v:voltage_sag

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electrical:12v:voltage_sag [2022/03/16 13:18]
frater_secessus [do nothing] 		electrical:12v:voltage_sag [2022/03/16 13:39]
frater_secessus [shorten the circuit]
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-Extreme example:  During heavy charging the controller might see 14v instead of the battery's 13v.  This 14v -> 13v difference is called voltage sag.  A similar thing happens in reverse when consuming power.  The battery might be 12.5v but an inverter running a big load might "see" 11.5v at its own terminals and shut off.  +Extreme example:  During heavy charging the controller might see 14v instead of the battery's 13v.  This 14v -> 13v difference is called voltage sag.  A similar thing happens in reverse when consuming power.  The battery might be 12.5v but an inverter running a big load might "see" 11.5v at its own terminals and shut off prematurely.((from the user's point of view)).  It also makes it difficult to assess [[electrical:depth_of_discharge|state of charge]] of lead batteries by voltage.
  
 +Sag presents special challenges when charging [[electrical:12v:drop-in_lifepo4|lithium]] battery banks.    Since the majority of lithium's usable power is found in an **extremely narrow voltage range**((about 0.5v wide)) sag can result in wildly unpredictable/inconsistent charging.
 ===== approaches ===== ===== approaches =====
  
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 ==== do nothing ==== ==== do nothing ====
  
-This is the majority position since most are unaware of the issue, or don't judge it to be important.  +This is the majority position since most are unaware of the issue, or don't judge it to be important.  And it may //not// be a problem since since 
 + 
 +  - solar-only charging is often low-current charging, minimizing charge-induced sag  
 +  - lead-chemistry batteries often have a range of Absorption and Float [[electrical:solar:charge_controller_setpoints|setpoints]] (see below)
  
  
 ==== shorten the circuit ==== ==== shorten the circuit ====
  
-A shorter wiring run will have less sag than a longer run.  For this reason charging sources are mounted **as close to the battery bank as possible**.  +All other things being equal, a **shorter wiring run will have less sag** than a longer run.  For this reason charging sources are mounted **as close to the battery bank as possible**.   
 + 
  
  
electrical/12v/voltage_sag.txt · Last modified: 2024/03/10 13:58 by frater_secessus

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