Both sides previous revision
Previous revision
Next revision
|
Previous revision
Next revision
Both sides next revision
|
electrical:12v:deep_cycle_battery [2018/12/06 11:22] frater_secessus [6v golf cart batteries] |
electrical:12v:deep_cycle_battery [2019/10/01 12:54] frater_secessus [lithium chemistries] |
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 === | ==== carbon FLA ==== |
| |
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 limits hard sulfation that can form in PSOC scenarios. | 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 limits hard sulfation that can form in PSOC scenarios. |
| |
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)) |
| |
In the more exotic form Firefly makes the Oasis battery with carbon foam. | |
| |
===== VRLA ===== | ===== VRLA ===== |
This type of VRLA battery gelatinizes the electrolyte to stabilize it. While renowned for their duty cycles, they are rarely used in campers. | This type of VRLA battery gelatinizes the electrolyte to stabilize it. While renowned for their duty cycles, they are rarely used in campers. |
| |
| ==== Carbon foam AGM === |
| |
| Firefly makes the Oasis (AGM) battery with carbon foam. Claimed benefits are: |
| * 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. |
===== 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)) |
===== lithium chemistries ===== | ===== lithium chemistries ===== |
| |
In theory **LifePO4 lithium batteries** should be near perfect for boondocking. | 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 ==== |
| [[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. |
| |
| |
| |
* 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: |
* 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]] |
| |
Other lithium chemistries like **"Li-ion" and "Li-po"** are rarely used. They are prone to thermal runaway (fire) and 3S packs do not line up well with 12v use. They are fully charged at 12.6v and and 80% discharged at ~11.2v.((3.73v per cell, https://www.rcgroups.com/forums/showthread.php?2953565-Lipo-Voltage-After-80-Discharge)) These lower voltages may trigger low voltage disconnect on devices that expect lead-acid range voltages. | ==== Non-LiFePO4 lithium-ion ==== |
| |
| Non-LiFeP04 Li-ion [called "li-ion" hereafter] are usually built in [[electrical:12v:parallel_serial|3S configuration]] and so run lower voltages than LFP or lead. Usable cell voltage is 4.2v - 3v, yielding bank voltage of **12.6v - 9v**.((https://batteryuniversity.com/learn/article/confusion_with_voltages)) This lower voltage may trip [[electrical:12v:lvd|Low Voltage Disconnect]] on [[electrical:inverter|inverters]] or [[food:refrigeration|refrigerators]]. |
| |
| |
| 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. |
| |
| **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. |
| |
| |
| |
| **Pro:** |
| * About half the cost of LFP for the same Ah capacity |
| * widely available |
| |
| |
| **Con:** |
| * overcharging or physical damage can cause a runaway condition (ie fire) |
| * voltage mismatch of 3S to nominal 12v systems |
| |
7S banks make a decent 24v bank. They are 29.4v fully charged and 80% discharged at 26.11v, compared to lead acid's 29.6v max voltage and 24.2v 50% DoD cutoff. This could preclude alternator charging, however. | |
| |