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electrical:12v:deep_cycle_battery [2022/01/26 17:09]
princess_fluffypants [Deep cycle batteries] |
electrical:12v:deep_cycle_battery [2024/04/15 01:00] (current)
frater_secessus [Chain Store Batteries] |
| ====== Deep cycle batteries ====== | ====== Deep cycle batteries ====== |
| |
| 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 but do not need to be fully charged every day. They are very tolerant of [[electrical:12v:psoc|partial charging]]. | 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]]. |
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| 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). |
| **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 | **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 |
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| ---- | ===== specs ===== |
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| ===== popular Deep-Cycle Lead batteries ===== | * Ah (Amp-hours) - the rated [[electrical:12v:battery_capacity|capacity]] of the battery. The 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. |
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| This is "The short list" of battery makes & models that have proven popular and reliable over the years. | |
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| === 6v golf cart batteries === | |
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| 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)) | |
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| 6v golf cart batteries were //designed// for deep cycle use. They are extremely heavy and generally wired in series to make a 12v bank. | ===== Popular Deep-Cycle Lead batteries ===== |
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| | 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. |
| |
| === Trojan T-105 === | === Trojan T-105 === |
| 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)) |
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| ==== Chain Store Batteries ==== | 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. |
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| {{ 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/)) | |
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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]]. 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)) | |
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| **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. | |
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| 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. | |
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| ---- | |
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| ===== Types of Lead batteries ===== | ===== Types of Lead batteries ===== |
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| | === 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 - Valve Regulated Lead Acid ==== | ==== VRLA - Valve Regulated Lead Acid ==== |
| * 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). |
| 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. | 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. |
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| "Lead crystal" batteries may actually be gel, since they 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)) | === lead crystal === |
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| | 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]] |
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| | 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)) |
| |
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| * 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. | * 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: |
| | |
| | > 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]]. 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. |
| | |
| | **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. |
| | |
| | |
| | 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. |
| | |
| | ==== Telco backup batteries ==== |
| | |
| | Telcos and other companies that need battery backup rotate their AGM batteries out regularly; these find their way onto the used market on pallets for relatively low prices. |
| | |
| | These backup batteries are not meant to cycle, vandweller style. They are designed to live on Float forever then suddently dump their power when grid power goes down. |
| | |
| | Can you make them work for you? Maybe, but people who can squeeze some use out of them already know what they are doing. |
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| ===== Lithium chemistries ===== | ===== Lithium chemistries ===== |
| |
| Lithium battery banks are lighter, more tolerant of abuse, 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 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. |
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