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electrical:batterycide [2018/06/30 20:58]
frater_secessus [murdering flooded lead-acid] |
electrical:batterycide [2024/07/17 21:41] (current)
frater_secessus [Battery murder] |
| | 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 ====== | ====== 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)) | //Battery murder// (or //Batterycide//) is the murder of batteries by abuse, misuse, inappropriate charging, 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 or [[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 they would invest in better quality batteries. | 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 ===== | ===== murdering flooded lead-acid ===== |
| Flooded lead-acid (FLA) batteries are the most resillient to mistreatment but they too can be killed. | 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.)) | * 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 soon enough; fully charging each day is best. | * 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 charging fully; they need a [[electrical:12v:charging#absorption_stage|long Absorption stage]] at manufacturer-recommended voltage to reverse normally-occurring ("soft") sulfation.((http://support.rollsbattery.com/support/solutions/articles/5964-battery-sulfation)) \\ [[electrical:generator#charging_batteries|Generator-only charging]] can cause this unless the generator runs the necessary number of hours it takes to complete Absorption. \\ 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]]. | * 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. Maximum discharge is typically limited to 50% [[electrical:depth_of_discharge|depth of discharge]]. | * 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. | * allowing the cells to get low on distilled water. Check them 1x/month or so until you learn their personality. |
| | * exposing them to heat, as in an engine bay |
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| ===== murdering AGM ===== | ===== murdering AGM ===== |
| AGM have benefits but are easier to murder. | [[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 | * 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. | * 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)). | * Equalization. **Do not equalize AGM**!((lifeline excepted)). |
| * the lead-acid list above | * 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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| * overvoltage. [[electrical:12v:lifepo4_batteries_thread|13.8v is a safe upper limit]] 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. | * 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. Lithium chemistries do not care about partial state of charge so use that to your advantage. | * 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 | * exposure to high heat |
| * attempting to charge at below freezing | * attempting to charge at below freezing |
