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opinion:frater_secessus:agm2lifepo4 [2023/12/28 12:08] frater_secessus [Can I still use my existing DC-DC charger for alternator charging?] |
opinion:frater_secessus:agm2lifepo4 [2024/03/23 13:13] (current) frater_secessus [shore power charging] |
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* charging only above freezing 32F/0C | * charging only above freezing 32F/0C | ||
- what your existing charging system provides (or can be configured to provide). | - what your existing charging system provides (or can be configured to provide). | ||
+ | * alternator voltage and rating if a [[electrical: | ||
+ | * [[electrical: | ||
+ | * [[electrical: | ||
- | If the existing system cannot be configured to meet LFP's needs then you are looking at replacing some components. For more specific guidance please share details about your setup, use case, budget, and priorities. | + | If the existing system cannot be configured to meet LFP's needs within [[electrical: |
Note: **undercharging lithium is not an issue** unless you are running out of power. This is a radical change from lead-battery charging. | Note: **undercharging lithium is not an issue** unless you are running out of power. This is a radical change from lead-battery charging. | ||
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==== Will I need a special LFP solar charge controller? ==== | ==== Will I need a special LFP solar charge controller? ==== | ||
- | Probably not, assuming your existing [[electrical: | + | Probably not, assuming your existing [[electrical: |
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Some controllers do use temperature sensing to cut off lithium charging near the freezing point. | Some controllers do use temperature sensing to cut off lithium charging near the freezing point. | ||
- | Note that having a temp probe left over from lead battery charging does not mean low-temp cutoff is supported in the controller. | + | Note that having a temp probe left over from lead battery charging does not mean low-temp cutoff is supported in the controller. |
+ | |||
+ | In addition, some batteries have a low temperature charging disconnect built into the BMS, or internal [[opinion: | ||
===== alternator charging ===== | ===== alternator charging ===== | ||
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* 1.0C - typical limit enforced by BMS | * 1.0C - typical limit enforced by BMS | ||
- | From the battery' | + | From the battery' |
As the Battle Born quote above suggests, for average LFP banks and average cargo van alternators these criteria will often be met with no reconfiguration. | As the Battle Born quote above suggests, for average LFP banks and average cargo van alternators these criteria will often be met with no reconfiguration. | ||
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- | IF **other forms of shore power charging are available** or **shore power charging will last at least overnight** the [[electrical: | + | IF **other forms of shore power charging are available** or **shore power charging will last at least overnight** the [[electrical: |
If **shore power charging is the only source of charging** or if **time on the charger is limited** then a more aggressive, expensive, higher-capacity multistage charger may be warranted. | If **shore power charging is the only source of charging** or if **time on the charger is limited** then a more aggressive, expensive, higher-capacity multistage charger may be warranted. | ||
+ | If the van will **be on shore power for an extended period** (days, weeks, months) then a small single-stage converter charger set to quite low voltage (13.2v?) would hold the battery at middling states of charge. | ||
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- | [Note from secessus: | + | [Note from secessus: |