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electrical:12v:lifepo4_batteries_thread [2017/04/14 09:42] frater_secessus [Suitability for RV use] |
electrical:12v:lifepo4_batteries_thread [2017/10/28 17:54] frater_secessus [three stage chargers] |
LiFePO4 | LiFePO4 |
* can take full current during charging; there are no //stages// in the lead-acid sense | * can take full current during charging; there are no //stages// in the lead-acid sense |
* can cycle down to very low SoC (20%) vs 50% for lead acid | * can use more nominal capacity than lead-acid (80-90% v. 50% [[electrical:depth_of_discharge|depth of discharge]]) |
* are not damaged by low SoC | * are not damaged by low SoC |
* can be mounted vertically or on a thin edge (but not flat)((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-234.html#post1452743)) | * can be mounted vertically or on a thin edge (but not flat)((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-234.html#post1452743)) |
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==== three stage chargers ==== | ==== three stage chargers ==== |
LFP batteries do not require multi-stage charging like lead-acid batteries; they are **charged until full and charging is stopped**. LFP does not have an absorption phase like LA((LFP will pull full current until very nearly full)) and does not need floating in the LA sense((due to low self-discharge rates)). | LFP batteries do not require multi-stage charging like lead-acid batteries; they are [[electrical:12v:charging#charge-and-stop|charged until full and then charging is stopped]]. LFP does not have an absorption phase like LA((LFP will pull full current until very nearly full)) and does not need floating in the LA sense((due to low self-discharge rates)). |
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That said, smart chargers //can// be used to charge LFP. Maine Sail describes the thought process of utilizing LA smart chargers with LiFePO4: | That said, smart chargers //can// be used to charge LFP. Maine Sail describes the thought process of utilizing LA smart chargers with LiFePO4: |
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There are important differences between how RVers/boaters and Electric Vehicles (EVs) charge and discharge LFP battery banks. EV batteries are used aggressively: charged at high current to full and drained at high current to empty. This can cause individual cells to get out of sync, voltage-wise, with others and warrant a BMS. | There are important differences between how RVers/boaters and Electric Vehicles (EVs) charge and discharge LFP battery banks. EV batteries are used aggressively: charged at high current to full and drained at high current to empty. This can cause individual cells to get out of sync, voltage-wise, with others and warrant a BMS. |
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| In Fractional C scenarios BMS failures may cause more damage than they prevent.((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-post2421606.html#post2421606)) |
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* RV | * RV |
* On solar **blars** does a short 14.v "absorption" by a 13.4v "float". He notes the float is high-ish but that the sun goes down so it will not be at that voltage a long time.((http://www.cheaprvliving.com/forums/Thread-Lithium-Ion-has-anyone-considered-these-batteries?pid=160365#pid160365)) When charging from shore power through a converter he does a very short "absorption" at 14.2v followed a 13.25v "float".((http://www.cheaprvliving.com/forums/Thread-Lithium-Ion-has-anyone-considered-these-batteries?pid=160365#pid160365)) | * On solar **blars** does a short 14.v "absorption" by a 13.4v "float". He notes the float is high-ish but that the sun goes down so it will not be at that voltage a long time.((http://www.cheaprvliving.com/forums/Thread-Lithium-Ion-has-anyone-considered-these-batteries?pid=160365#pid160365)) When charging from shore power through a converter he does a very short "absorption" at 14.2v followed a 13.25v "float".((http://www.cheaprvliving.com/forums/Thread-Lithium-Ion-has-anyone-considered-these-batteries?pid=160365#pid160365)) |
* **29chico** charges at 13.9v-13.9v((http://www.cheaprvliving.com/forums/Thread-Renogy-100w-suitcase-and-Lithium?pid=195318#pid195318)) and recommends going no lower than 12.6v, approx. 10% SoC.((http://www.cheaprvliving.com/forums/Thread-Renogy-100w-suitcase-and-Lithium?pid=195318#pid195318)) | * **29chico** charges at 13.8v-13.9v((http://www.cheaprvliving.com/forums/Thread-Renogy-100w-suitcase-and-Lithium?pid=195318#pid195318)) and recommends going no lower than 12.6v, approx. 10% SoC.((http://www.cheaprvliving.com/forums/Thread-Renogy-100w-suitcase-and-Lithium?pid=195318#pid195318)) |
John61ct recommends charging at 13.8v and floating at 13.2v, when float is required by the controller.((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-368.html#post2318216)) | * **John61ct** recommends charging at 13.8v and floating at 13.2v, when float is required by the controller.((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-368.html#post2318216)) |
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===== notable voltage reference points ===== | ===== notable voltage reference points ===== |
| **13.40**| 3.35|**Terrycharging Vfloat** | | | **13.40**| 3.35|**Terrycharging Vfloat** | |
| 13.25| 3.31|20% Depth of Discharge | | | 13.25| 3.31|20% Depth of Discharge | |
| 12.80| 3.20|50% Depth of Discharge FIXME. Recommended for long-term storage.((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-172.html#post1201146)) | | | 12.80| 3.20|50% Depth of Discharge FIXME. Long-term storage.((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-172.html#post1201146)) | |
| 12.40| 3.10|80% Depth of Discharge | | | 12.40| 3.10|80% Depth of Discharge. Best for storage?((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-384.html#post2383574)) | |
| **11.80**| 2.95|**Terrycharging Low Voltage Disconnect**. Min safe non-BMS voltage.((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-103.html#post1140470)) | | | **11.80**| 2.95|**Terrycharging Low Voltage Disconnect**. Min safe non-BMS voltage. ((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-103.html#post1140470)) | |
| 11.20| 2.80|100% Depth of Discharge((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-104.html#post1140620)). Low Voltage Cutoff.((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-109.html#post1142567)) | | | 11.20| 2.80|100% Depth of Discharge((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-104.html#post1140620)). Low Voltage Cutoff.((http://www.cruisersforum.com/forums/f14/lifepo4-batteries-discussion-thread-for-those-using-them-as-house-banks-65069-109.html#post1142567)) | |
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