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electrical:12v:charging [2019/05/17 18:09]
frater_secessus [charging AGM batteries] added C
electrical:12v:charging [2020/05/13 09:18]
frater_secessus
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 [[lifestyle:​words_of_wisdom|Words of wisdom]]: “Three stage chargers are easier on your batteries, charge them faster, fuller and help you use less water”((https://​handybobsolar.wordpress.com/​the-rv-battery-charging-puzzle-2/​)) – HandyBob [[lifestyle:​words_of_wisdom|Words of wisdom]]: “Three stage chargers are easier on your batteries, charge them faster, fuller and help you use less water”((https://​handybobsolar.wordpress.com/​the-rv-battery-charging-puzzle-2/​)) – HandyBob
 +
 +
 +> A [[[electrical:​shore_power|shore power]]] charger is a stiff source with unlimited energy and time. Your solar is a very soft source of unknown power and only a few hours to get the job done.  - sunking((https://​www.solarpaneltalk.com/​forum/​off-grid-solar/​batteries-energy-storage/​299490-bulk-absorb-float-equalize-what-does-it-mean#​post299490))
 +
  
 ====== charging deep cycle batteries ====== ====== charging deep cycle batteries ======
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-In general, manufacturers of lead chemistries ​specifiy a charging at [[electrical:​12v:​battery_capacity|C/​10]];​ this assumes more charging time than solar power allows.((http://​www.cheaprvliving.com/​forums/​showthread.php?​tid=23606&​pid=288284#​pid288284))  ​Regularly cycled banks may benefit from firmer charging ​at C/3.  There may not be a practical maximum charging rate for cycled FLA batteries //when charged from solar//​. ​ As Sternwake put it when describing a C/1.5 (!) charging scenario, "solar is not instant max output."​((http://​www.cheaprvliving.com/​forums/​showthread.php?​tid=23606&​pid=288284#​pid288284))+In general, manufacturers of flooded ​lead chemistries ​specify ​charging at [[electrical:​12v:​battery_capacity|C/​10]] ​to C/5; this assumes more charging time than solar power allows.((http://​www.cheaprvliving.com/​forums/​showthread.php?​tid=23606&​pid=288284#​pid288284))  ​AGM are typically charged ​at C/5 to C/3.  There may not be a practical maximum charging rate for cycled FLA batteries //when charged from solar//​. ​ As Sternwake put it when describing a C/1.5 (!) charging scenario, "solar is not instant max output."​((http://​www.cheaprvliving.com/​forums/​showthread.php?​tid=23606&​pid=288284#​pid288284))
 ===== three stage charging ===== ===== three stage charging =====
  
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 ==== absorption stage ==== ==== absorption stage ====
-The absorption stage, sometimes called //​acceptance//​ or //boost//, is a constant voltage stage during which the battery is brought to full charge. ​ This stage requires a **great deal of time** but decreasing amounts of current.  ​+The absorption stage, sometimes called //​acceptance//​((which makes sense)) ​or //boost//((doesn'​t make sense!)), is a constant voltage stage during which the battery is brought to full charge. ​ This stage requires a **great deal of time** but decreasing amounts of current.  ​ 
 + 
 +Absorption **begins when the battery reaches the absorption voltage** ([[electrical:​12v:​electrical notation|Vabs]],​ 14.8v in our example) and **ends when the battery tapers off current acceptance** to something like [[electrical:​12v:​battery_capacity|C/​100]] ("End Absorb",​ "​endAmps"​), ​ and/or when a period of time has elapsed. ​  
 + 
 +Example: ​ if you have a 100Ah battery bank and the manufacturer states that endAmps is C/100, then the battery is fully charged when it is only accepting 1A of current((100Ah/​100 = 1A)) **at Vabs**. ​ An endAmps recommendation of C/200 would be the battery accepting 0.5A of current.((100Ah/​200 = 0.5A)) at Vabs.   
 + 
 + 
 +In practice absorption takes longer when the battery has been discharged deeply and shorter when it has not.((http://​www.cheaprvliving.com/​forums/​Thread-Can-a-solar-panel-and-charge-controller-over-charge-a-battery?​pid=96965#​pid96965)) 
 + 
 +**Mythbuster:​** although it is commonly said that Vabs is attained at ~80% capacity... 
 + 
 +> charge current affects the SOC transition point from bulk to absorption charging - MaineSail((https://​marinehowto.com/​how-fast-can-an-agm-battery-be-charged/​)) 
 + 
 +MaineSail found that  
 + 
 +  * charging AGM at C/2.5 (max rate) resulted in the battery being 63.3% "​full"​ at Vabs and being fully charged in **5hrs, 30 minutes** 
 +  * charging AGM at C/5 (min rate) resulted in the battery being 77.4% "​full"​ at Vabs and being fully charged in **5hrs, 42 minutes** 
  
-Absorption **begins when the battery reaches the absorption voltage** ([[electrical:​12v:​electrical notation|Vabs]],​ 14.8v in our example) and **ends when the battery tapers off current acceptance** to something like C/100 ("End Absorb",​ "​endAmps"​), ​ and/or when a period of time has elapsed. ​ In practice absorption takes longer when the battery has been discharged deeply and shorter when it has not.((http://​www.cheaprvliving.com/​forums/​Thread-Can-a-solar-panel-and-charge-controller-over-charge-a-battery?​pid=96965#​pid96965)) 
  
 Some controllers will allow the user to configure the time or ratio of capacity/​current (C///​n//​). ​ Sternwake says: Some controllers will allow the user to configure the time or ratio of capacity/​current (C///​n//​). ​ Sternwake says:
-> If your charge controller only holds [absorption] voltage for an hour or two, that is likely not enough time. As long as [there is a load] and you cycle the battery daily, you could set float voltage to 14.8v [to match absorption] without worry. Only when you stop cycling the battery do you need to return float voltage to more regular 13.2v levels. Premature application of float voltage by automatic charging sources is a battery killer.((http://​www.cheaprvliving.com/​forums/​Thread-Solar-or-Battery-Problem?​pid=229883#​pid229883))+> If your charge controller only holds [absorption] voltage for an hour or two, that is likely not enough time. As long as [there is a load] and you cycle the battery daily, you could set float voltage to 14.8v((for example - secessus)) ​[to match absorption] without worry. Only when you stop cycling the battery do you need to return float voltage to more regular 13.2v((for example - secessus)) ​levels. Premature application of float voltage by automatic charging sources is a battery killer.((http://​www.cheaprvliving.com/​forums/​Thread-Solar-or-Battery-Problem?​pid=229883#​pid229883)) 
 + 
  
 ==== float stage ==== ==== float stage ====
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 ===== charging other chemistries ===== ===== charging other chemistries =====
  
-See [[electrical:​12v:​lifepo4_batteries_thread#​charging|LiFePO4 (lithium) charging]] ​+See [[electrical:​12v:​lifepo4_batteries_thread#​charging|LiFePO4 (lithium) ​bare cell charging]] ​
  
 ===== equalization ===== ===== equalization =====
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   - ambient temperature as measured by the charger. ​ This can be different from the actual battery temp due to position, relative height to the battery, or if the charger gets confused by its own heat.    - ambient temperature as measured by the charger. ​ This can be different from the actual battery temp due to position, relative height to the battery, or if the charger gets confused by its own heat. 
   - in the absence of actual measurements the charger will likely use the 77F laboratory standard.   - in the absence of actual measurements the charger will likely use the 77F laboratory standard.
 +
 +This automatic voltage tweaking for temperature may result in your actual battery voltages being observably higher in cold temps and lower in hot temps. ​
  
 ===== watering batteries ====== ===== watering batteries ======
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-A [[http://​amzn.to/​2gEtVwL|battery waterer]] can make the job easier, and does not require one to judge water level visually.+A [[http://​amzn.to/​2gEtVwL|battery waterer]] can make the job easier, and does not require one to judge water level visually.  The water "​bloops"​ as it fills and stops blooping when the water is at the correct level
  
 Batteries that are older, in poorer health, or are charged at higher voltages will be "​thirstier"​. ​ Check water levels 1x/month until you know how they behave. Batteries that are older, in poorer health, or are charged at higher voltages will be "​thirstier"​. ​ Check water levels 1x/month until you know how they behave.
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 **Manual chargers** will not be affected by load as they are controlled by the user. **Manual chargers** will not be affected by load as they are controlled by the user.
 +
 +
 +===== battery voltage while charging =====
 +
 +Battery Voltage = Battery Voc((resting voltage)) + (Charge Current x Ri((internal resistance)))
  
  
  
electrical/12v/charging.txt · Last modified: 2020/06/23 10:56 by frater_secessus