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electrical:12v:deep_cycle_battery [2018/12/06 12:11] frater_secessus [Gel cell] |
electrical:12v:deep_cycle_battery [2019/10/01 12:58] frater_secessus [BMS] |
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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 === | + | ==== 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: | ||
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===== 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. |
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+ | |||
+ | Lithium banks come in three main forms: | ||
+ | * " | ||
+ | * DIY banks, often " | ||
+ | * 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" | ||
+ | * 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)) | ||
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+ | ==== LiFePO4 ==== | ||
+ | |||
+ | [[https:// | ||
+ | In theory **LifePO4 | ||
+ | |||
+ | [[https:// | ||
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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:// | + | BMS-equipped LFP banks should be charged according to manufacturer' |
+ | |||
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- | The batteries can be charged with either a [[electrical: | ||
- | Technomadia charge to 14.2v, use a minimal " | ||
Further reading: | Further reading: | ||
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* CF [[http:// | * CF [[http:// | ||
- | Other lithium chemistries like **" | ||
- | 7S banks make a decent 24v bank. They are 29.4v fully charged and 80% discharged | + | |
+ | |||
+ | ==== Non-LiFePO4 lithium-ion ==== | ||
+ | |||
+ | Non-LiFeP04 Li-ion [called " | ||
+ | |||
+ | |||
+ | 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** | ||
+ | 24v banks in general | ||
+ | |||
+ | |||
+ | |||
+ | **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 | ||
+ | |||