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electrical:12v:deep_cycle_battery [2019/03/07 14:31]
frater_secessus [LiFePO4]
electrical:12v:deep_cycle_battery [2020/05/13 10:05] (current)
frater_secessus [manufacturers]
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-Common setpoints (check your manufacturer'​s recommendation):​+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))   * 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   * Vfloat 13.2v when not deeply cycled; ​ 13.8v when cycled daily
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 In the milder form, carbon is added to the negative plates. ​ Trojan claims up to 15% more cycles from the RE(("​Renewable Energy"​)) line than non-carbon FLA in PSOC 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)) In the milder form, carbon is added to the negative plates. ​ Trojan claims up to 15% more cycles from the RE(("​Renewable Energy"​)) line than non-carbon FLA in PSOC 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))
    
 +===== manufacturers =====
 +
 +
 +> Each manufacturer also has their own in-house brand, e.g. Delco for Johnson Controls and Deka for East Penn. Exide and US Battery use their corporate name for their battery brand as well. Trojan sells under the Trojan, Trillium, Reliant and Ranger brand names and Concorde sells under the Concorde and Lifeline brand names.... [Interstate is a label, not a manufacturer]... ​ The 4 big US battery makers offer a couple price and quality tiers for their customers to choose from, but generally batteries with the same specs (AH/RC, CCA, and BCI case size) will be essentially identical. Warranty, MSRP, etc. is set by the selling brand and may differ, but the physical product is the same. -- Gary RVRoamer((https://​www.irv2.com/​forums/​f59/​trojan-t-105-or-interstate-again-486470-2.html#​post5246144))
 +
 +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))
  
 ===== VRLA ===== ===== VRLA =====
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 ===== chain store batteries ===== ===== 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))  ​ {{ 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))  ​
 +
 +It's not foolproof, but seeing a CCA (Cold Cranking Amps) spec listed on the battery suggests it is //not// a deep cycle battery: ​
 +
 +> While it might be tempting to estimate the AH rating of a battery from its CCA rating, there is not a simple relationship between these two battery parameters.((https://​www.mathscinotes.com/​2016/​12/​relationship-between-battery-cold-cranking-amps-versus-capacity/​))
 +
 +
  
 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]].
  
-**Pro**: ​ Local and 24hr availability in stores can 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. ​
  
 **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 chemistries =====
 +
 +Lithium battery banks are lighter and have higher energy density than lead-acid batteries. ​ The main drawback is price.  ​
 +
 +
 +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.
 +  * 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
 +  * manufactured complete banks that do not mimic the physical shape of lead batteries ​
 +
 +==== BMS ====
 +Because of the very high energy density and sensitivity to temperature and voltage extremes, most Li banks are equipped with a Battery Management System (BMS) which monitors and controls the bank and the cells in it. 
 +
 +Depending on the BMS, features may include:
 +  * protection from overcharging individual cells
 +  * "top balancing"​ cells, getting cell voltages to match when fully charged
 +  * protection from over-discharge
 +  * protection from excess current in charging and/or discharging
 +  * prevention of charging when temps are too low((typically freezing or below))
 +
 +
 +
 +
 +
  
 ==== 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.
  
  
-In theory **LifePO4 lithium batteries** should be near perfect for boondockers who [[camping:​snowbirding|follow good weather]]. 
  
  
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   * can be damaged by heat   * can be damaged by heat
  
-For best life (and to decrease the likelihood of cell imbalance) Charge to 13.8v and disconnect voltage at 12.6v.((http://​www.cheaprvliving.com/​forums/​showthread.php?​tid=17442&​pid=195503#​pid195503)),​ ((http://​www.cruisersforum.com/​forums/​f14/​lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069.html#​post740260)),​ ((http://​www.cruisersforum.com/​forums/​f14/​lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-4.html#​post747996)),​ ((http://​www.cruisersforum.com/​forums/​f14/​lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-7.html#​post812380))+BMS-equipped LFP banks should be charged according to manufacturer'​s specs Bare cell charging is discussed [[electrical:12v:lifepo4_batteries_thread|on its own page]]. 
 + 
 + 
  
-The batteries can be charged with either a [[electrical:​solar:​charge_controller|charge controller]] with a LifePO4 profile, or a [[electrical:​12v:​charging|smart charger]] with programmable setpoints. ​ If the latter, something like a "​Bulk"​ charge at 13.8, minimal "​absorption",​ and "​float"​ in the 13.25-13.4v range.((http://​www.cheaprvliving.com/​forums/​showthread.php?​tid=14960&​pid=160365#​pid160365)) 
-Technomadia charge to 14.2v, use a minimal "​absorption",​ and "​float"​ at as the setpoint , float at 13.6v.((http://​www.technomadia.com/​2012/​09/​a-year-on-lithium-rv-batteries/​)) 
  
 Further reading: Further reading:
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   * 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-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]]   * CF [[http://​www.cruisersforum.com/​forums/​f14/​lifepo4-house-bank-using-smarthousepower-bms-40389.html|LiFePO4 house batteries]]
 +
 +
 +
  
 ==== Non-LiFePO4 lithium-ion ==== ==== Non-LiFePO4 lithium-ion ====
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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.  ​+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. ​  
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 **Con:** **Con:**
   * overcharging or physical damage can cause a runaway condition (ie fire)   * overcharging or physical damage can cause a runaway condition (ie fire)
-  * voltage mismatch ​- FIXME+  * voltage mismatch ​of 3S to nominal 12v systems
  
  
  
electrical/12v/deep_cycle_battery.1551997912.txt.gz · Last modified: 2019/03/07 14:31 by frater_secessus