Can I Top Balance LifePo4 Battery Cells at 3.7v
Home » News » Can I Top Balance LiFePO4 Battery Cells at 3.7v?

Can I Top Balance LiFePO4 Battery Cells at 3.7v?

    The first thing most people do when they receive LiFePO4 battery cells is to top balance the cell. About how to top balance LiFePO4 battery cells please read here.

    One question we get repeatedly is “Can I top balance at 3.7V?”

    The reason for this question is that many DC power supplies have a minimum voltage adjustment range of 0.1V. It is impossible to set the voltage to 3.65V. The only option is to top balance with 3.6V or 3.7V.

    This gives rise to two concerns.

    1. whether the battery cells will not reach true top balance if they are charged with 3.6V.
    2. if 3.7V is used for charging, the maximum rated voltage of the battery cell is exceeded, and whether this will damage the battery cell.

    Here, we recommend using 3.6V for top balancing when your DC power supply cannot be set to 3.65V.

    While 3.7V over the rated maximum voltage of 3.65V for LiFePO4 battery cells is not too high, it is, after all, over the limit. Although it will not necessarily cause damage to the LiFePO4 battery cells, there is always a risk.

    For LiFePO4 battery cells that we plan to use for more than 5 years, we need to take this risk out of the equation.

    So is charging with 3.6V enough to bring LiFePO4 battery cells to top balance?

    The answer is yes, 3.6V is enough to bring LiFePO4 cells to top balance. According to the charging curve of LiFePO4 battery cells, when the battery cells are charged to 3.4V, the voltage rises very fast, and by 3.6V, the curve has also reached the rightmost part near the vertical end. The SOC(State of Charge) is close to 100% at this point.

    LiFePO4 charging curve
    LiFePO4 charging curve

    The correct way to top balance LiFePO4 using 3.6V

    In general we recommend the user to operate like this.

    1, Connect LiFePO4 battery cells in parallel and charge them with 3.4V or 3.5V.

    2, Continuously monitor the voltage of the battery cell. And fine tune the charging voltage to 3.6V when the voltage rises to 3.4V or 3.5V.

    3, pay close attention to the change of charging current, when the current gradually decreases to close to 0. disco

    4, (OPTION) charge again with 3.6V and observe the current. If the current is close to 0, it means the top balance is done. If the current is not close to 0, you will also observe that it drops quickly. When it drops close to 0, disconnect and leave it for some more time.

    After the above steps, the SOC of the battery cell is over 99.9%. In fact it can already be seen as achieving top balance.

    Finally, you can connect the battery cells in series and form a battery pack with BMS. In the future, the BMS will balance all the cells without interruption to maintain the efficient output of the whole battery pack.

    There are many Lithium Iron Phosphate battery suppliers, but Energie Panda provides you brand new grade A LiFePO4 battery cells.

    Any question and inquiries please send email to, we answer quickly.

    JK Active Balance BMS JK-B1A8S20P JK-B2A8S20P USER MANUAL
    JK Active Balance BMS JK-B1A8S20P JK-B2A8S20P User Manual

    JK-B1A8S20P/JK-B2A8S20P is JK active balance BMS for 4S or 8S LiFePO4 battery pack. The maximum bala…

    Server Rack Battery VS DIY LiFePO4 Battery
    Server Rack Battery VS DIY LiFePO4 Battery

    More and more people are demonstrating an interest in server rack batteries. Before server rack batt…

    JBD 48V 100A BMS SP25S003 Specification
    JBD 48V 100A BMS Specification

    JBD-SP25S003 is an intelligent BMS solution designed by Jiabaida Electronic Technology Co., Ltd. for…

    Charge Profile for LiFePO4 Batteries
    Charge Profile for LiFePO4 Batteries

    Many customers ask for the LiFePO4 charging profile after receiving the battery cells and building t…

    Solar Energy System Guidelines for Homeowners
    Solar Energy System Guidelines for Homeowners

    Since 2019, as long-life, deep-cycle lithium iron phosphate (LiFePO4) cells begin to be used in sola…

    LiFePO4 Battery Cell Vendor Code List
    LiFePO4 Battery Cell Vendor Code List

    In post “How to Quickly Identify Fake LFP Battery Cells Part 3 – QR Code“, we introduced…

    Leave a Reply

    Your email address will not be published. Required fields are marked *