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electrical:batterycide [2016/11/20 11:13]
frater_secessus created |
electrical:batterycide [2023/08/24 22:52] (current)
princess_fluffypants [murdering lithium] |
| ====== Batterycide ====== | Words of Wisdom: |
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| | > Over many years of capacity testing hundreds and hundreds of batteries, flooded, GEL and AGM I have yet to see a lead acid battery that could delivers its full storage potential at anything less than 0.75%((C/80)) in tail current at absorption voltage. MaineSail((https://marinehowto.com/how-fast-can-an-agm-battery-be-charged/)) |
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| | ====== Battery murder ====== |
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| | //Battery murder// (or //Batterycide//) is the murder of batteries by newbs (new users), poor quality chargers, etc. The term is commonly used by SternWake: //"my goal here is to prevent batterycide."//((http://www.cheaprvliving.com/forums/Thread-Intro-Solar-Questions?pid=192042#pid192042)) |
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| | It is so common for new RVers to wreck their first set of house batteries that some recommend using cheap [[electrical:12v:deep_cycle_battery#chain_store_batteries|wally world batteries]] as sacrificial lambs to the learning process.((http://www.cheaprvliving.com/forums/Thread-Putting-together-system?pid=176052#pid176052)) As the RVers learns more and gets charging set up correctly they would invest in better quality batteries and have them last several years. |
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| | ===== murdering flooded lead-acid ===== |
| | Flooded lead-acid (FLA) batteries are the most resillient to mistreatment but they too can be killed. |
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| | * leaving them at [[electrical:12v:psoc|partial state of charge]], resulting in //irreversible// sulfation((AKA "hard" sulfation. The battery undergoes "soft" sulfation and desulfation during normal charging/discharging.)) Fully charging each day is optimal. Fully charging //almost// every day is acceptable. |
| | * not charging at [[electrical:solar:charge_controller_setpoints|manufacturer-recommended Absorption voltage]] (Vabs) to reverse normally-occurring ("soft") sulfation. This is most commonly caused by [[electrical:12v:alternator|isolator-only]] charging since the house bank is being charged at ((or slightly below)) alternator voltage. \\ Less commonly, [[electrical:solar|Solar]]-only charging can cause this problem if the [[electrical:solar:sizing|battery capacity is too great for the solar output]].((http://support.rollsbattery.com/support/solutions/articles/5964-battery-sulfation)) |
| | * not holding Vabs for [[electrical:severe_battery_use#increasing_effective_absorption_duration|sufficient duration]] so that absorption current drops to manufacturer-recommended levels. [[electrical:generator#charging_batteries|Generator-]] or [[electrical:12v:b2b|DC-DC charging]] can cause this unless the charger runs the necessary number of hours it takes to complete Absorption. |
| | * discharging too deeply. Discharge with lead-chemistries is typically limited to 50% [[electrical:depth_of_discharge|depth of discharge]] as a compromise between cycle life and bank size. |
| | * allowing the cells to get low on distilled water. Check them 1x/month or so until you learn their personality. |
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| | ===== murdering AGM ===== |
| | [[opinion:frater_secessus:the_case_for_agm|AGM have benefits]] but are easier to murder. |
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| | * the lead-acid list above((except the part about low water levels)) |
| | * overvoltage |
| | * Incorrect Absorption setpoints. AGM is commonly Absorped at <= 14.4v while FLA is commonly Absorped higher (at 14.7v-14.8v). Check your manufacturer's recommendation and do not exceed it. Overvoltage causes irrepairable damage by outgassing, and AGM cannot be topped off again like FLA. |
| | * Equalization. **Do not equalize AGM**!((lifeline excepted)). |
| | * Low current charging. Cheap AGM require [[electrical:12v:battery_capacity|C/5]] current minimum in Bulk, and expensive ones require C/3. |
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| | ===== murdering lithium ===== |
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| | * overvoltage. [[electrical:12v:lifepo4_batteries_thread|13.8v is a safe upper limit]] without BMS and will charge the bank completely. Some experienced folk use slightly higher voltages for faster charging but it must be terminated quickly as the bank approaches 100% state of charge. Exception: Lithium banks with BMS typically overcharge intentionally to balance cells. The overcharge is consumed by resistors and does not actually go into the cell. |
| | * long periods of 100% state of charge; cease all charging at 100% and only charge that high if you know some loads will be applied immediately. |
| | * IF you're storing the van or know you're not going to be using the batteries for more than a couple days, it's strongly recommended to leave lithium batteries at 50-80% SOC. Lithium chemistries do not care about partial state of charge, and actually prefer it.. |
| | * exposure to high heat |
| | * attempting to charge at below freezing |
| | * poor quality BMS |
| | * high [dis]charge rates without BMS |
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| "Batterycide" is the murder of batteries by newbs (new users), poor quality chargers, etc. The term is commonly used by SternWake: //"my goal here is to prevent batterycide."//((http://www.cheaprvliving.com/forums/Thread-Intro-Solar-Questions?pid=192042#pid192042)) | |
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| It is so common for new RVers to wreck their first set of house batteries that some recommend using cheap Costco golf cart 6v batteries as sacrificial lambs to the learning process. As the RVers learns more they would invest in better quality batteries. | |
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