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electrical:12v:deep_cycle_battery [2020/06/19 11:18]
frater_secessus [Gel cell]
electrical:12v:deep_cycle_battery [2023/10/27 12:33] (current)
frater_secessus [specs]
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 ====== Deep cycle batteries ====== ====== Deep cycle batteries ======
  
-Deep cycle batteries are batteries which are designed to be [[electrical:depth_of_discharge|deeply discharged]] (//DoD//) between full charges.  For longest life, lead-acid chemistries (flooded or sealed/AGM) are discharged down to about 50% State of Charge (//SoC//) and then recharged fully every day.+Deep cycle batteries are batteries which are designed to have an extreme [[electrical:depth_of_discharge|depth of discharge]] (//DoD//) between full charges.  For longest life, lead-acid chemistries (flooded or sealed/AGM) are discharged down to about 50% State of Charge (//SoC//) and then recharged **fully** every day.  Similarly, Lithium-chemistry batteries can be discharged to about 20% SoC, and do not need to be fully charged every day.  They are very tolerant of [[electrical:12v:psoc|partial charging]].
  
-In campervan scenarios the batteries hit their lowest Soc just before dawn and are fully charged sometime before sunset (the earlier the better).+In campervan scenarios the batteries hit their lowest SoC just before dawn and are fully charged sometime before sunset (the earlier the better).
  
 Batteries can be [[electrical:12v:charging|charged with a smart or three-stage charger]] for optimal performance and longevity. Batteries can be [[electrical:12v:charging|charged with a smart or three-stage charger]] for optimal performance and longevity.
  
-===== DoD vs. duty cycles ===== 
-{{ http://popupbackpacker.com/wp-content/uploads/2013/12/Trojan-Depth-of-Charge-Table.jpg?200}} 
-Deep cycle batteries are most commonly discharged to 50% DoD((50% SoC)), but can be discharged to other levels with radical results in the life of the battery. 
  
-On this graph from Trojan we see the following pattern:+**Note: This article assumes useage of 12v lead chemistries.** If you're using Lithium, this information is not as applicable.  Please see the [[electrical:12v:drop-in_lifepo4|Drop-in Lithium batteries]] article, or for the more industrious the [[electrical:12v:lifepo4_batteries_thread|Lithium Battery DIY thread]] page
  
-  * discharging to 20% DoD((80% SoC)) daily will yield ~3000 duty cycles (~8.2 years of daily use, ~$0.21/KWh((https://saurorja.org/2011/08/30/lead-acid-is-the-cheapest-battery-conditions-apply/))) +===== specs =====
-  * discharging to 50% DoD((50% SoC)) daily will yield ~1200 duty cycles (~3.3 years of daily use, ~$0.21/KWh) +
-  * discharging to 80% DoD((80% SoC)) daily will yield ~500 duty cycles (~1.4 years of daily use, ~$0.26/KWh)+
  
-Since drawing down 20% vs50% is the same cost over time it might be best to **aim for 20% DoD and cycle to 50DoD when needed**.  This would decrease the number of battery replacements while getting maximum use.  +  * Ah (Amp-hours) - the rated [[electrical:12v:battery_capacity|capacity]] of the batteryThe basic concept is that a 100Ah battery could theoretically deliver 10A for 10 hours (10A x 10h = 100Ah).  In practice deep cycle batteries are not drained to 0%, and the rate of discharge can affect the apparent capacity.  
 +  Wh (Watt-hours) - like Ah above, only multiplied by the nominal voltage.   
 +    100Ah of lead is 1200Wh (100Ah x 12.0v).   
 +    * 100Ah of LiFePO4 is 1280Wh (100Ah x 12.8v) 
 +  * cycles - the number of times the battery can be charged and discharged before being considered End Of Life.((EoL is typically considered the point where the battery can no longer produce 80% of its rated output)).    Cycles are usually calculated using a particular [[electrical:12v:battery_capacity|C rate]] and [[electrical:depth_of_discharge|depth of discharge]].   
 +    * Lead is typically rated at the 1/20th the current as Ah (5A for a 100Ah battery) down to 50% DoD. 
 +    * LiFePO4 is typically rated at the 1/5th the current as Ah (20A for a 100Ah battery) down to 80% DoD. 
 +    * both maximum and recommended charge/discharge currents are given [[electrical:12v:battery_capacity|in C]] or Amps. 
  
-Drawing down to 80% DoD consistently is 24% more expensive and requires much more replacement effort. [Those things are //heavy//! -- Secessus] Occasional/emergency drops to 80% DoD **followed by full charging the next day** will not inflict meaningful damage to the battery. 
  
  
  
 +===== Popular Deep-Cycle Lead batteries =====
  
 +6v golf cart batteries are the gold standard for a true deep-cycle lead chemistry battery.  They were //designed// for deep cycle use, and with proper maintenance can last for years.  They are extremely heavy and two batteries are generally wired in series to make a 12v bank.
  
 +> Words of Wisdom:  "The worst 6v  GC-2 battery is still a better deep cycle battery than 99.98% of flooded 12v batteries sold in deep cycle applications." -- SternWake((http://www.cheaprvliving.com/forums/showthread.php?tid=18955&pid=215263#pid215263))
  
- +This is "The short list" of Golf Cart battery makes models that have proven popular and reliable over the years.
- +
- +
- +
-===== flooded lead acid ===== +
-The most common deep cycle battery is flooded lead acid (FLA).  They are least expensive in the long run but do require checking/refilling the cells with distilled water occasionally. +
- +
- +
-Common [[electrical:solar:charge_controller_setpoints|setpoints]] (check your manufacturer's recommendation): +
-  * charge [[electrical:12v:battery capacity|C/10 to C/5]]((10A-20A per 100Ah of battery capacity)) +
-  * Vfloat 13.2v when not deeply cycled;  13.8v when cycled daily +
-  * Vabs 14.7v - 14.8v +
- +
- +
- +
- +
- +
- +
- +
-==== 6v golf cart batteries ==== +
- +
-Words of Wisdom:  "The worst 6v  GC-2 battery is still a better deep cycle battery than 99.98% of flooded 12v batteries sold in deep cycle applications." -- SternWake((http://www.cheaprvliving.com/forums/showthread.php?tid=18955&pid=215263#pid215263)) +
- +
-6v golf cart batteries were //designed// for deep cycle use.  They are extremely heavy and generally wired in series to make a 12v bank.+
  
 === Trojan T-105 === === Trojan T-105 ===
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 NAPA carries a GC-2 made by Exide.((http://www.irv2.com/forums/f106/house-batteries-232920-2.html#post2417703)) NAPA carries a GC-2 made by Exide.((http://www.irv2.com/forums/f106/house-batteries-232920-2.html#post2417703))
  
-==== carbon FLA ====+===== popular lithium batteries =====
  
-Some manufacturers attempt to get around the [[electrical:12v:psoc|Partial State of Charge]] limitations of lead chemistries by using carbon in some form.  The idea is that the addition of carbon increases the internal conductivity of the negative plate under challenging conditions, minimizing hard sulfation that can form in PSOC scenarios.+See [[electrical:12v:drop-in_lifepo4#brands_and_specs|this listing]] on the drop-in lithium page.
  
-In the milder form, carbon is added to the negative plates: 
  
-> Battery manufacturers have begun including high purity conductive graphite in the negative active material of their batteries. They have found that this type of carbon helps to maintain the essential active material conductivity that helps to control sulfation.((https://batteryvitamin.net/sulfation_remedies_demystified)) 
  
 +===== Battery Health =====
  
-  * Rolls calls this "[[http://support.rollsbattery.com/support/solutions/articles/245858-advanced-nam|Advanced NAM]]"((negative [something] material?)) and claims 15% faster charging, increased capacity, and increased cycle life.  They state that this type of battery may have higher [[electrical:solar:charge_controller_setpoints|endAmps]] due to less internal resistance.((http://support.rollsbattery.com/support/solutions/articles/246380-end-amps-or-return-amps)) +==== DoD vsduty cycles ====
-  * Trojan claims up to 15% more cycles from the RE(("Renewable Energy")) line with "smart carbon"((https://www.trojanbattery.com/new-products/smart-carbon/)) than non-carbon FLA in solar-charging use.((http://www.trojanbattery.com/new-products/smart-carbon/))  At this writing the cost premium for this <=15% increase in cycles is 21%.(($175 for T-105RE vs $145 for T-105))  This would be an extra 9 months of life assuming a 5yr lifespan. +
- +
  
-===== manufacturers =====+=== lead chemistries ==
 + 
 + 
 +{{ http://popupbackpacker.com/wp-content/uploads/2013/12/Trojan-Depth-of-Charge-Table.jpg?200}} 
 +Lead deep cycle batteries are most commonly discharged to 50% DoD((50% SoC)), but can be discharged to other levels with radical results in the life of the battery. 
 + 
 +On this graph from Trojan we see the following pattern: 
 + 
 +  * discharging to 20% DoD((80% SoC)) daily will yield ~3000 duty cycles (~8.2 years of daily use, ~$0.21/KWh((https://saurorja.org/2011/08/30/lead-acid-is-the-cheapest-battery-conditions-apply/))) 
 +  * discharging to 50% DoD((50% SoC)) daily will yield ~1200 duty cycles (~3.3 years of daily use, ~$0.21/KWh) 
 +  * discharging to 80% DoD((80% SoC)) daily will yield ~500 duty cycles (~1.4 years of daily use, ~$0.26/KWh) 
 + 
 +Since drawing down 20% vs. 50% is the same cost over time it might be best to **aim for 20% DoD and cycle to 50% DoD when needed**.  This would decrease the number of battery replacements while getting maximum use.   
 + 
 +Drawing down to 80% DoD consistently is 24% more expensive and requires much more replacement effort. [Those things are //heavy//! -- Secessus] Occasional/emergency drops to 80% DoD **followed by full charging the next day** will not inflict meaningful damage to the battery. 
 + 
 +=== lithium chemistries === 
 + 
 +Lithium cycle ratings are typically assume: 
 + 
 +  * 80% DoD 
 +  * [[electrical:12v:battery_capacity|C]]/5 charge rates 
 +  * at human-comfortable temperatures 
 + 
 +[[electrical:12v:drop-in_lifepo4#an_approach_to_greater_longevity|Cycles may be increased]] by avoiding high voltages, high currents, and avoiding both very low and very high states of charge.  
 + 
 + 
 + 
 + 
 +==== Battery Lifespan ==== 
 + 
 +Batteries are typically replaced when they can no longer provide 80% of their rated capacity.   This requires fully charging, then discharging at the 20-hr rate (C/20) until the battery is depleted.  This is impractical with house batteries that are in actual use. 
 + 
 +Because of this, we use indirect methods to assess battery health.   
 + 
 +> Quickly rising to absorption voltage during bulk and never seeing tail current drop down to previous levels are good indicators that the battery is in a declined or seriously declining state.  mainesail((https://www.cruisersforum.com/forums/f14/my-aging-northstar-group-27-a-179072.html#post2312172)) 
 + 
 + 
 +Tail current (aka endAmps, finishing amps) for healthy lead batteries is typically between C/200 and C/100 (0.5A to 1.0A at Vabs for per 100Ah of capacity).  If tail current cannot get down to (C/50) 2A we can assume there is trouble on the horizon.   
 + 
 + 
 +> I have yet to see a lead acid battery that could delivers its full storage potential at anything less than 0.75%((ie, C/133)) in tail current at absorption voltage. -- mainesail((https://marinehowto.com/how-fast-can-an-agm-battery-be-charged/)) 
 + 
 + 
 +The rise to absorption voltage is rarely useful in the field since: 
 + 
 +  - solar charging alone is rarely able to hit charge current maximums 
 +  - alternator charging is rarely able to hit Vabs 
 + 
 +People charging off larger [[electrical:12v:b2b|DC-DC]], [[electrical:converter|shore power]], or [[electrical:generator|generators]] may be able gauge the speed at which the bank comes up to Vabs. 
 + 
 + 
 +==== Premature failure ==== 
 + 
 +Lead batteries tend to lose capacity very gradually over time, and are typically replaced when they only have 80% of their rated capacity. If a dying battery still meets your needs feel free to [[electrical:severe_battery_use|use it until it croaks]].  
 + 
 +Lead batteries can fail prematurely from [[electrical:batterycide|abuse and/or undercharging]] (usually gradual), or physical failure like cells shorting out (usually sudden).  Shorted batteries will tend to overheat when charged/discharged. 
 + 
 +> On FLAs, the definitive way to diagnose a shorted cell is to disconnect the battery and apply a reasonably heavy load (say, C/2 or so). Electrolyte in the shorted cell, if one is present, will boil.((https://www.cruisersforum.com/forums/f14/battery-temperature-243203.html#post3287905)) 
 + 
 + 
 + 
 +----  
 + 
 +===== Manufacturers =====
  
  
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 Interstate batteries made by US Battery have "U" prefixes.((https://www.solarpaneltalk.com/forum/off-grid-solar/batteries-energy-storage/14996-trojan-t-105-vs-crown-235-and-what-s-wrong-with-parallel?p=195949#post195949)) Interstate batteries made by US Battery have "U" prefixes.((https://www.solarpaneltalk.com/forum/off-grid-solar/batteries-energy-storage/14996-trojan-t-105-vs-crown-235-and-what-s-wrong-with-parallel?p=195949#post195949))
  
-===== construction =====+See also [[https://web.archive.org/web/20210415142809/http://herehydro.weebly.com/uploads/9/3/9/1/93913/battery_manufacturers_and_brand_names_list.pdf|this archived PDF]] that attempted to document who makes what battery. 
 + 
 +===== Types of Lead batteries =====
  
 Generally speaking, lead batteries fall into three broad groups Generally speaking, lead batteries fall into three broad groups
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   - **hybrid/marine** - plates tend to have middling thickness.  They may have calcium-doped negative plates and antimony-doped negative plates.((http://necon.co.za/batttech.php?w=1366&h=768#openModal))   - **hybrid/marine** - plates tend to have middling thickness.  They may have calcium-doped negative plates and antimony-doped negative plates.((http://necon.co.za/batttech.php?w=1366&h=768#openModal))
  
 +
 +==== FLA - Flooded Lead Acid ====
 +
 +The most common deep cycle battery is flooded lead acid (FLA).  They are least expensive in the long run but do require checking/refilling the cells with distilled water occasionally.
 +
 +
 +Common [[electrical:solar:charge_controller_setpoints|setpoints]] (check your manufacturer's recommendation):
 +  * charge [[electrical:12v:battery capacity|C/10 to C/5]]((10A-20A per 100Ah of battery capacity))
 +  * Vfloat 13.2v when not deeply cycled;  13.8v when cycled daily
 +  * Vabs 14.7v - 14.8v
  
  
 +=== watering FLA ===
  
 +  - check to ensure plates are at least //covered// with liquid
 +  - charge fully
 +  - check water level again, adding to fill mark
  
 +This order is important because the electrolyte expands a bit as it charges, so filling completely //then// charging could result in spillage and loss of acid.
  
-===== VRLA =====+==== VRLA - Valve Regulated Lead Acid ====
  
 [[lifestyle:words_of_wisdom|Words of Wisdom]]:  "Generally, gel and AGM batteries have about 20% less capacity, cost about two times more, and have a shorter cycle life than comparable flooded lead acid batteries." -- Trojan((http://www.trojanbattery.com/Tech-Support/FAQ/BatterySelection.aspx)) [[lifestyle:words_of_wisdom|Words of Wisdom]]:  "Generally, gel and AGM batteries have about 20% less capacity, cost about two times more, and have a shorter cycle life than comparable flooded lead acid batteries." -- Trojan((http://www.trojanbattery.com/Tech-Support/FAQ/BatterySelection.aspx))
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 ==== AGM ==== ==== AGM ====
  
-This type of VRLA battery stabilizes the electrolyte in an Absorbent fiberGlass Mat (AGM).+Note:  High quality AGM makers include "Odyssey, Lifeline, Northstar, Fullriver, Rolls and Firefly".((https://www.cruisersforum.com/forums/f14/agm-battery-failure-two-sets-in-two-years-239438-6.html#post3228496))   
 + 
 + 
 +This type of VRLA battery stabilizes the electrolyte in an Absorbent fiberGlass Mat (AGM).   
 + 
  
   * PRO   * PRO
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     * no outgassing under normal conditions     * no outgassing under normal conditions
   * CON   * CON
-    * generally **double the cost** of FLA for about 20% less capacity((http://www.trojanbattery.com/Tech-Support/FAQ/BatterySelection.aspx))+    * generally **double the cost** of FLA for similar capacity((http://www.trojanbattery.com/Tech-Support/FAQ/BatterySelection.aspx))
     * Premium AGM need **much more charging current** than flooded, and it may be more than solar-only setups can provide.((http://www.cheaprvliving.com/forums/Thread-How-much-of-an-issue-is-battery-off-gassing?pid=144704#pid144704)) The charging rate given by Lifeline, a respected AGM manufacturer, is //at least// C/5((20A per 100Ah of battery capacity)) or battery life will be affected. They also say it is ok to charge up to 5C((500A per 100Ah of battery capacity!)) (!).((http://lifelinebatteries.com/wp-content/uploads/2015/12/manual.pdf))  Odyssey specifies C/2.5 charging rates for their batteries.((40A per 100Ah of battery capacity))((http://www.odysseybattery.com/documents/ODYSSEY_Battery_Reconditioning_Charge_Procedure.pdf))     * Premium AGM need **much more charging current** than flooded, and it may be more than solar-only setups can provide.((http://www.cheaprvliving.com/forums/Thread-How-much-of-an-issue-is-battery-off-gassing?pid=144704#pid144704)) The charging rate given by Lifeline, a respected AGM manufacturer, is //at least// C/5((20A per 100Ah of battery capacity)) or battery life will be affected. They also say it is ok to charge up to 5C((500A per 100Ah of battery capacity!)) (!).((http://lifelinebatteries.com/wp-content/uploads/2015/12/manual.pdf))  Odyssey specifies C/2.5 charging rates for their batteries.((40A per 100Ah of battery capacity))((http://www.odysseybattery.com/documents/ODYSSEY_Battery_Reconditioning_Charge_Procedure.pdf))
     * even cheap AGM require more current than flooded:  minimum C/5, max C/3.(20A-33A per 100Ah of battery capacity).     * even cheap AGM require more current than flooded:  minimum C/5, max C/3.(20A-33A per 100Ah of battery capacity).
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-Also see [[http://www.cheaprvliving.com/forums/Thread-Intro-Solar-Questions?pid=192023#pid192023|SternWake's advice on charging AGM batteries]].+Also see  
 + 
 +  * [[http://www.cheaprvliving.com/forums/Thread-Intro-Solar-Questions?pid=192023#pid192023|SternWake's advice on charging AGM batteries]]. 
 +  * this [[https://web.archive.org/web/20181024083504/https://www.practical-sailor.com/issues/32_3/features/Deep-Cycle-Battery-Test_5244-1.html|archived test]] of deep cycle AGM by Practical Sailor magazine 
 + 
 +Historical note:  the original use for AGM was for long-term stationary floating on shore power for backup/UPS purposes, as one finds in industrial backups or in the bases of cell towers. In long-term stationary use the liquid electrolyte in flooded batteries can stratify, causing degradation.  The electrolyte in AGM(((and gel)) types cannot move freely and so will not stratify.  Telcos and other industries typically replace the batteries after X years on float duty and sell them on the surplus market.  They are not made for frequent cycling but still may represent a good value.   
  
 ==== Gel cell ==== ==== Gel cell ====
  
-This type of VRLA battery gelatinizes the electrolyte to stabilize it.  While renowned for their duty cycles, they are rarely used in campers due to cost, limited charging max similar to flooded((C/5, https://www.trojanbattery.com/pdf/datasheets/Motive_T1275-AGM_DS.pdf)), and sensitivity to overvoltage.+This type of VRLA battery gelatinizes the electrolyte with SiO2 (silicon dioxide) to stabilize it.  While renowned for their exceptional duty cycle life, they are rarely used in campers due to cost, limited charging max similar to flooded((C/5, https://www.trojanbattery.com/pdf/datasheets/Motive_T1275-AGM_DS.pdf and https://www.qsl.net/wb3gck/gel-cell.htm)), and sensitivity to overvoltage. 
  
 +=== lead crystal ===
 + 
 +These appear to be an AGM variant with some gel:
  
 +>> The plate group was taken apart, which showed that the separator is a standard AGM (absorbent glass mat) with double layer. Additionally, a very small amount of gellified electrolyte was found on top of the plates. -- - [[https://www.dropbox.com/s/zz7vf6k8y36btfq/Memo%20%28internal%29%20Betta%20Lead%20Crystal%2026032013.pdf?dl=0|leaked pdf  describing a Betta battery teardown]]
  
-==== Carbon foam AGM === +The "Lead crystal" name appears to refer to the gel component, since manufacturers typical claim the electrolyte is made of SiO2.((http://azimuthsolar.ca/getting-silicon-dioxide-sio2-batteries-charging-instructions/)),((https://www.solarpaneltalk.com/forum/solar/the-pros-and-cons-of-solar-energy/22713-why-are-there-no-lead-crystal-battery-distributors-in-the-usa-or-canada?p=272482#post272482))  
 + 
 + 
 + 
 +==== Carbon foam AGM ==== 
  
 Firefly makes the Oasis (AGM) battery with carbon foam. Claimed benefits are: Firefly makes the Oasis (AGM) battery with carbon foam. Claimed benefits are:
   * increased current acceptance   * increased current acceptance
   * Absorption stage required only 1x/month or so rather than every day or so.  Since Absorption stage is long-duration, this can cut down charging time considerably.   * Absorption stage required only 1x/month or so rather than every day or so.  Since Absorption stage is long-duration, this can cut down charging time considerably.
-===== chain store batteries ===== + 
-{{ https://i5.walmartimages.com/asr/523d2f9f-6552-48c6-928c-9eebf09ab0e9_1.3ffce13c71014acbc0a6c469b62333dc.jpeg?150}}"Deep cycle" / marine batteries found at Walmart and similar chains are not actually deep cycle batteries.  Real 12v deep cycle batteries like the [[https://www.ebay.com/sch/items/?_nkw=trojan+T-1275&_sacat=&_ex_kw=&_mPrRngCbx=1&_udlo=&_udhi=&_sop=12&_fpos=&_fspt=1&_sadis=&LH_CAds=&rmvSB=true|Trojan T-1275]] are large, expensive, and very rarely seen in campers.((http://www.cheaprvliving.com/forums/Thread-Everstart-vs-Everstart-Maxx-batteries-at-Wal-Mart?pid=167108#pid167108))  +==== Carbon Flooded Lead Acid ==== 
 + 
 +Some manufacturers attempt to get around the [[electrical:12v:psoc|Partial State of Charge]] limitations of lead chemistries by using carbon in some form.  The idea is that the addition of carbon increases the internal conductivity of the negative plate under challenging conditions, minimizing hard sulfation that can form in PSOC scenarios. 
 + 
 +In the milder form, carbon is added to the negative plates: 
 + 
 +> Battery manufacturers have begun including high purity conductive graphite in the negative active material of their batteries. They have found that this type of carbon helps to maintain the essential active material conductivity that helps to control sulfation.((https://batteryvitamin.net/sulfation_remedies_demystified)) 
 + 
 + 
 +  * Rolls calls this "[[http://support.rollsbattery.com/support/solutions/articles/245858-advanced-nam|Advanced NAM]]"((negative [something] material?)) and claims 15% faster charging, increased capacity, and increased cycle life.  They state that this type of battery may have higher [[electrical:solar:charge_controller_setpoints|endAmps]] due to less internal resistance.((http://support.rollsbattery.com/support/solutions/articles/246380-end-amps-or-return-amps)) 
 +  * Trojan claims up to 15% more cycles from the RE(("Renewable Energy")) line with "smart carbon"((https://www.trojanbattery.com/new-products/smart-carbon/)) than non-carbon FLA in solar-charging use.((http://www.trojanbattery.com/new-products/smart-carbon/))  At this writing the cost premium for this <=15% increase in cycles is 21%.(($175 for T-105RE vs $145 for T-105))  This would be an extra 9 months of life assuming a 5yr lifespan. 
 + 
 +==== Chain Store Batteries ==== 
 + 
 +{{ https://i5.walmartimages.com/asr/523d2f9f-6552-48c6-928c-9eebf09ab0e9_1.3ffce13c71014acbc0a6c469b62333dc.jpeg?150}}"Deep cycle" / marine batteries found at Walmart and similar chains are [[https://marinehowto.com/what-is-a-deep-cycle-battery/|not actually deep cycle batteries]] and cannot be expected to last very long in deep cycle use.  Real 12v deep cycle batteries like the [[https://www.ebay.com/sch/items/?_nkw=trojan+T-1275&_sacat=&_ex_kw=&_mPrRngCbx=1&_udlo=&_udhi=&_sop=12&_fpos=&_fspt=1&_sadis=&LH_CAds=&rmvSB=true|Trojan T-1275]] are large, expensive, and very rarely seen in campers.((http://www.cheaprvliving.com/forums/Thread-Everstart-vs-Everstart-Maxx-batteries-at-Wal-Mart?pid=167108#pid167108))  
  
 It's not foolproof, but seeing a CCA (Cold Cranking Amps) spec listed on the battery suggests it is //not// a deep cycle battery:  It's not foolproof, but seeing a CCA (Cold Cranking Amps) spec listed on the battery suggests it is //not// a deep cycle battery: 
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-Having said that, if one is aware of the limitations of the battery it can play a role in the campervan, particularly as a "learner battery" that the [[electrical:batterycide|beginner often murders]].  Lifespan on these batteries can be maximized by cycling lightly, perhaps 20% [[electrical:depth_of_discharge|depth of discharge]].+Having said that, if one is aware of the limitations of the battery it can play a role in the campervan, particularly as a "learner battery" that the [[electrical:batterycide|beginner often murders]].  Lifespan on these batteries can be maximized by cycling lightly, perhaps 20% [[electrical:depth_of_discharge|depth of discharge]].  They can also be used for people who are not away from shore power very long: 
 + 
 +> A drycamper's needs are quite different from the [RV park power] pedestal crowd. If heavily cycling a battery then most 12v jars are a serious compromise and require special charging treatment... The person who drives from pedestal to pedestal and only occasionally camps without hookups might be well served by a 12v dual purpose battery... - landyacht318((https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/28237856/print/true.cfm)) 
 + 
 + 
  
 **Pro**:  Local and 24hr availability in stores can be valuable.  Warranties are nationwide;  save your receipt as it is usually required.  **Pro**:  Local and 24hr availability in stores can be valuable.  Warranties are nationwide;  save your receipt as it is usually required. 
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 **Con**: Significantly less capacity than a real deep cycle bank; a group 27 wally world battery has about 1/2 the Ah capacity.  Drastically reduced longevity when cycled to 50% DoD as with most campervan usage patterns.   **Con**: Significantly less capacity than a real deep cycle bank; a group 27 wally world battery has about 1/2 the Ah capacity.  Drastically reduced longevity when cycled to 50% DoD as with most campervan usage patterns.  
  
-===== lithium chemistries ===== 
  
-Lithium battery banks are lighter and have higher energy density than lead-acid batteries.  The main drawback is price.  +Further reading:  [[https://marinehowto.com/what-is-a-deep-cycle-battery/|this page]] with further explanation and teardowns to show the difference between deep cycle and "deep cycle" batteries.  
 + 
 +---- 
 + 
 + 
 +===== Lithium chemistries ===== 
 + 
 +Lithium battery banks are lighter, can handled more current((up to BMS limits)), and have higher energy density than lead-acid batteries.  The main drawback is price. See the [[electrical:12v:drop-in_lifepo4|Lithium batteries]] page.
  
  
 Lithium banks come in three main forms: Lithium banks come in three main forms:
   * "drop-in" batteries that are the same size and general voltage range as the lead batteries they replace.  Example:  [[https://amzn.to/2oVGNWj|Battle Born]]  BMS is built in.   * "drop-in" batteries that are the same size and general voltage range as the lead batteries they replace.  Example:  [[https://amzn.to/2oVGNWj|Battle Born]]  BMS is built in.
-  * DIY banks, often "bare" cells 3.2v cells in [[electrical:12v:parallel_serial|4S]] configuration, with or without BMS.  These are not the same size or shape as lead batteries +  * DIY banks, often "bare" cells 3.2v cells in [[electrical:12v:parallel_serial|4S]] configuration, with or without BMS.  These are not the same size or shape as lead batteries, and require a moderate amount of knowledge to use without blowing yourself up. 
-  * manufactured complete banks that do not mimic the physical shape of lead batteries +  * Manufactured complete banks that do not mimic the physical shape of lead batteries 
  
 ==== BMS ==== ==== BMS ====
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 ==== LiFePO4 ==== ==== LiFePO4 ====
  
-[[https://amzn.to/2oVGNWj|{{ https://m.media-amazon.com/images/I/61Z6qdh47cL._AC_UL320_SEARCH213888_ML3_.jpg}}]] 
-In theory **LifePO4 (LFP) lithium batteries** should be near perfect for boondockers who [[camping:snowbirding|follow good weather]]. 
  
-[[https://amzn.to/2oVGNWj|Battle Born]] presently dominates the drop-in 12v lithium market.+[[https://amzn.to/2oVGNWj|{{ https://m.media-amazon.com/images/I/61Z6qdh47cL._AC_UL320_SEARCH213888_ML3_.jpg?100}}]]
  
 +LiFePO4 drop-ins like [[https://amzn.to/2oVGNW|Battle Born]] and [[https://amzn.to/3ibPepi|SOK]]have moved to [[electrical:12v:drop-in_lifepo4|their own page]].
  
- +LiFePO4 DIY info can be found on on Will Prowse'pages about [[https://www.mobile-solarpower.com/raw-lifepo4-deals-page.html|cells]] and [[https://www.mobile-solarpower.com/raw-lifepo4-deals-page-676969.html|BMS]], and in [[electrical:12v:lifepo4_batteries_thread|this distillation of a 10-year thread]] on the Crusisers & Sailing forum. 
- +
-**Pro:** +
-  * can accept significant current throughout charging, unlike lead-acid which accepts relatively current during [[electrical:12v:charging#absorption_stage|absorption]]. +
-  * can be cycled down to 80% [[electrical:depth_of_discharge|depth of discharge]] compared to lead-acid's 50%. +
-  * higher number of rated cycles than lead-acid, perhaps 2000.((http://www.pbase.com/mainecruising/lifepo4_on_boats)) +
-  * half the weight, smaller size +
-  * no mounting restrictions +
-  * no venting required +
-  * not rated over 20 hours like lead-acid;  LiFePO4 Ah are rated at .5C.((http://www.pbase.com/mainecruising/lifepo4_on_boats)) +
-  * 4S LiFePO4 cells are a good fit for nominal 12v systems.  They are fully charged at ~13.8v and 80% discharged around 12.6v.   +
- +
-**Con:** +
-  * much more expensive +
-  * cannot be charged below freezing (use is ok) +
-  * can be damaged by heat +
- +
-BMS-equipped LFP banks should be charged according to manufacturer'specs.  Bare cell charging is discussed [[electrical:12v:lifepo4_batteries_thread|on its own page]]. +
- +
- +
- +
- +
- +
-Further reading: +
-  * [[electrical:12v:LiFePO4 Batteries thread|Synopsis]] of Cruisers and Sailing forums' LiFePO4 thread. +
-  * CF [[http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069.html|LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks]] +
-  * CF [[http://www.cruisersforum.com/forums/f14/lifepo4-batteries-okay-tear-me-apart-36530.html|LiFePO4 batteries]]   +
-  * CF [[http://www.cruisersforum.com/forums/f14/lifepo4-house-bank-using-smarthousepower-bms-40389.html|LiFePO4 house batteries]] +
  
  
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 There are hobbyists who build **4S packs** and undercharge the cells to only 3.7v.  This gives an operating range of 14.8v - 12v, a much better fit for nominal 12v systems. The downside is this configuration only uses 58% of the cells' capacity and will require more cells to achieve the same amount of Ah.  The cells could be fully charged then the output regulated back to more normal 12v voltage ranges. There are hobbyists who build **4S packs** and undercharge the cells to only 3.7v.  This gives an operating range of 14.8v - 12v, a much better fit for nominal 12v systems. The downside is this configuration only uses 58% of the cells' capacity and will require more cells to achieve the same amount of Ah.  The cells could be fully charged then the output regulated back to more normal 12v voltage ranges.
  
-**7S builds** make a decent **24v bank**.  They are 29.4v fully charged and 21v discharged, compared to lead acid's 29.6v max voltage and 24.2v 50% DoD cutoff.  Discharging 7s li-ion to 24v((3.42v/cell) could help avoid LVD, making 35% of the cells' capacity unusable.   +**7S builds** make a decent **24v bank**.  They are 29.4v fully charged and 21v discharged, compared to lead acid's 29.6v max voltage and 24.2v 50% DoD cutoff.  Discharging 7s li-ion to 24v((3.42v/cell)) could help avoid LVD, making 35% of the cells' capacity unusable.   
 24v banks in general could preclude [[electrical:12v:alternator|alternator charging]], however. 24v banks in general could preclude [[electrical:12v:alternator|alternator charging]], however.
  
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   * overcharging or physical damage can cause a runaway condition (ie fire)   * overcharging or physical damage can cause a runaway condition (ie fire)
   * voltage mismatch of 3S to nominal 12v systems   * voltage mismatch of 3S to nominal 12v systems
- 
  
  
electrical/12v/deep_cycle_battery.1592579910.txt.gz · Last modified: 2020/10/11 19:48 (external edit)