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LiFePO4 discharge test at 20°C


LiFeYPO4 battery discharge characteristics under normal temperature (20°C).



18.Jun 2018
 
Latest articles

    16.Feb 2018
     
    3.2V LFP cell initial charging

    Question: How should new cells 3.2V  40AH, 60AH, 90AH, 100 AH, etc. be formed before first usage?

    Answer: The new 3.2V LFP cells delivered from the warehouse are partially charged. However before the first use, it is essential to charge each cell to full capacity. The initial charging should be done with the charging current set to less than 1C (typically 0.5C), till the voltage level of 4.0 V is reached.

    There is no other need for LFP 3.2V cells to be formatted or otherwise specially prepared for the use. After the first charge to full, the cell is ready to be used for use.

    The above charging rule is also applied to the initial charge after the cell has been unused or stored for a long time. If not used more than 1 month, it is recommended to make again an initial charge to full.

       ...more >>

    16.Feb 2018
     
    12V LP battery balancing and charging

    Question:  Can I charge the 12V LFP battery using a conventional auto-moto charger 12V?

    Answer:  With most of “cheap” car battery chargers you **cannot** charge the 12V LFP battery. Cheap chargers often end charging at 14V.  As a result the LFP batteries are not charged sufficiently. In order to charge to full you need to reach above 16V.

    If you have an “advanced” manageable charger, it can be used provided you can set the charge level to at least 16V.

    Simply said: you can charge with any kind of charger if you make sure that the battery voltage reaches at least 16V, but does not exceed the maximum limit of 17V.

     

    Question: What are the experiences of balancing 12V batteries, when, for example, four pieces of 12V/40Ah in the series?

       ...more >>

    16.Feb 2018
     
    You must charge the LiFePO4 before the first use!

    Charge levels

     

    You must charge before the first use!

    We remind all users of the LFP cells and LP batteries that the cells and batteries MUST be charged to full voltage level BEFORE assembling into a pack and before starting to be used.

    For the 3.2V cells, the full charge voltage level is 4.00V and the charging is described here.  For the 12V LP batteries the full charge voltage level is 16.00V. More details about the use of 12V batteries is here.

       ...more >>

    16.Feb 2018
     
    Using BMS to analyze the cell performance

    BMS settings charge voltage

     

    Why is the BMS needed for a LFP battery pack consisting of many cells?

    Answer: The Battery Management System (BMS) allows you to monitor the battery pack operation. Since the battery consists of a serial string of many cells, you need to monitor each cell to prevent from deep discharge or over charge.  The BMS will give you information about the cell voltage levels and can issue warnings if there is a problem with any of the cells.

    The BMS with balancing option will balance the cells (usually during charging) to make sure all cells have the same capacity (=voltage) levels.

    The BMS also allows data logging so that you can see the history of the operation of the each cell in the battery. This way you can detect if there is any problem with one or more cells in the battery pack.

    16.Feb 2018
     
    Charging individual cells using the regulated (laboratory) power supply

    Regulated laboratory charger

     

    Charging individual cells using the regulated (laboratory) power supply

    Many of the laboratory power supplies allow charging of the individual cells. Using such a regulated power supply is a suitable method for performing the initial charging or for the balancing of a single cell in a battery pack (by means of charging to a fixed voltage level).

    There are usually 3 steps to follow:  1) set the target voltage (open voltage) – without the connection of the battery (3.65 at the picture), 2) start charging and set the current to be used (3.0 A at the picture), 3) when the charger reaches the target voltage – it usually starts to reduce the charging current until a low value. (3.66 V reached at 0.04A). It is a time to stop charging and disconnecting the charger.

    16.Feb 2018
     
    Initial charging FAQ

    Initial charging FAQ

    Check these FAQ published on our blog to understand the initial battery charging

     

    We remind all users of the LFP cells and LP batteries that the cells and batteries MUST be charged to full voltage level BEFORE assembling into a pack and before starting to be used.  source

    The new 3.2V LFP cells delivered from the warehouse are partially charged. However before the first use, it is essential to charge each cell to full capacitysource

       ...more >>

    16.Feb 2018
     
    Maximal voltage during Initial charge of LiFePO4

    Maximal voltage during Initial charge of LiFePO4

     I want to make the initial charge of all the LiFePO4 cells to the same maximal voltage level of 4.0V. How can I do that?

     

    EDIT: This article gives the example of 4.00V charge level. The same information is to applied for charging to other voltage levels: e.g. 3.65V, 3.70V, 3.80V, 3.90V. Different voltage levels may be applied for initial charging based on the manufacturer specification.

    ANSWER: The best way it to find a power supply or a charger that will charge to the 4.0V directly.  Another solution is to charge using the laboratory power supply or the regulated power supply that allows to set the final (maximal) voltage limit. We suggest to check with the local electronic components suppliers for these products.

       ...more >>

    16.Feb 2018
     
    Initial charge voltage levels of LiFePO4

    Voltage levels of LiFePO

     

     Initial charge voltage levels

    Question: I wish to equip my workshop with the proper tools. Can you offer me following chargers: one model with cut off voltage at 3.65V, one model with cut off voltage at 3.80V and one model with cut off voltage at 4.00V?

    Answer: There is no need to have so many different chargers.  The typical chargers that are sold by GWL charge to 3.65V (for single cell).  Please see some additional comments.

       ...more >>

    09.Feb 2018
     
    How does GWL/Power support the customer’s co-operation?

    4x 12V 20AH batteries under test

    Please see the photo of our test setup for 12V 20A batteries in 4 series string. We want to demonstrate charging and discharging levels for this model pack.

    09.Feb 2018
     
    Sudden battery discharge

    Sudden discharge of LiFePO4

    FAQ: “Sudden” battery discharge

    I have bought a several of LFP cells and made the pack with them to replace the lead-acid battery in my houseboat. The LFP battery was working great and it gives much more capacity than the lead acid. However after several weeks of usage, I came back after the weekend and I found out that the battery is completely discharged. Why this happen?

    Please note that unlike the lead acid batteries, the LFP batteries will be completely damaged if you discharge them bellow the minimal voltage (usually >2.5V per cell, or bellow 10V for 12V battery). This may happen if you have some equipment that takes the power from the battery continually. Maybe you simply forget some light or some equipment „on“, and after few days the battery is deeply discharged and damaged forever.

       ...more >>

    09.Feb 2018
     
    LFP as starting battery

    LFP as starting battery

    LFP as a starting battery – two concerns

    Question: I want to use the LFP battery (4x 3.2V cells) for starting of my car. What SBM should I use to protect the battery?

    You cannot use a SBM to protect the starting battery. For starting the car, the current will be very high, hundreds or even nearly 1000 Amps, it is not possible to disconnect such high currents.

    WARNING: Additionally it is not possible to disconnect the battery from vehicle circuits. The car electronics may burn or become faulty of the battery is suddenly removed from the circuit, as a result of disconnection, during the operation (when the engine is running).

       ...more >>

    09.Feb 2018
     
    History of LiFePO4 Winston technology

    History of LiFePO4 technology

    Difference between Winston Battery and other brands (1)

    What is the primary difference between the Winston Battery LiFePO4 products and other brands that also offer prismatic cells?

    1. Technology history

    Thundersky Winston Battery

    The Thunder Sky Winston Battery company was the originator of the large capacity technology for the prismatic cells. The technology was created by Mr. Winston Chung. By means of partnerships with several companies TS-WB transferred the production facilities to partner factories. However the core know-how and technology processes were retained by Mr. Winston Chung.

       ...more >>

    09.Feb 2018
     
    A combined Energy solution - Alfons container

    Alfons solution Alfons container

    Alfons container Alfons container

    A combined Energy Solution - Alfons Container

    GWL/Power supplied the Winston Battery cells for the integrated hybrid energy solution called “Container Alfons”.  This solution integrates the energy from three sources - solar, wind and a backup diesel generator.

    Be sure to contact GWL/Power for more details and for the reference to this and similar projects. 

    09.Feb 2018
     
    Welcome in 2018

    Best wishes in 2018

    Welcome in 2018!

    It is the 10th year of our battery related activities. We started in 2008 with the support LiFePO4 high power industrial cells.  We keep working after the 10 years and we keep building on our experience over the many years. 

    Stay with us for more news and details. 

    The GWL/Power team!

    09.Feb 2018
     
    Operating temperature of LFP Cells

    Temperature of cells

    The temperature of the LFP cells

    What is the operating temperature of the LFP cells?

    The operating temperature of the LFP cells is based on the specification and the application.  There are several points to be clarified in this matter.  The first to clarify is the three different temperatures in relation to the batteries.

    The ambient temperature

    The ambient temperature is usually given as the air temperature of any environment where the batteries and related equipment are kept.  The ambient temperature is given at the specification of the cells.  It is also called the operation temperature.

       ...more >>

    09.Feb 2018
     
    Winston shipment in February

         Winston shipment February 2018 

        

     

    The shipment of Winston Battery cells

    The shipments of the Winston Battery cells are on the way, arriving in end of February and early March. Get ready for your orders. Contact the GWL Power team for more inquiries.  

    09.Feb 2018
     
    ThunderSky Winston new Factory

    Winston Factory

    Winston Battery New Factory – Winston Battery (Changtai) Limited

    All cells delivered since mid 2017 have been made in the new factory. The factory provides enough space to accommodate the growing demands for the LFP prismatic cells. 

    29.Jan 2018
     
    LFP battery discharged to ZERO volts

    FAQ - Frequently Asked Questions

    What is the 4.25 Volt level for LFP cells?

    It is the maximal charging level. When charging the voltage per cell must be limited to 4.25V and bellow. If the voltage exceeds 4.25V, the cell is getting internally damaged and the life span is shortened.

    What is the 3.2 Volt level for LFP cells?

    It is the nominal discharge voltage.  Please see the discharge voltage diagram. During the discharge the nominal voltage is 3.2V.

    What is the 2.5 Volt level for LFP cells?

    It is the minimal discharge voltage.  During discharge, the battery voltage must not drop bellow this level. When the voltage goes down to 2.5V the discharge must be stopped. If the voltage goes bellow 2.5V, the cell is getting internally damaged and the life span is shortened.

       ...more >>

    28.Jan 2018
     
    Charging a single cell from a 5V USB adapter

    ThunderSky 160AH capacity test

    Please see another test by JRR Nortec tetsing equipment. Base on this report, you can see the capacity of the 160Ah cell reaches the total of 165.4Ah. This makes 103% capacity level.


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