Forum Discussion

RolloMartins's avatar
RolloMartins
Explorer
Mar 26, 2022

Xantrex and Lithium Battery setup

I have a van conversion with solar+two 250amp lithium (Battleborn) batteries. The Xantrex is a 3012 3000w Freedom.
When on shore charge I turn the inverter on and it charges up to 14.1v. All seems fine and dandy.
Next day I will check it and it is at 13.5v.
I have a secondary alternator and it charges as well (when moving, obviously).
It seems to me that the charge should remain elevated and not drop. There is nothing on currently except of course the inverter and the digital readout for the microwave. Nothing else. Frig is off.
I wish I understood the electronics of this setup better.
Class B
  • Jim_Carolyn's avatar
    Jim_Carolyn
    Explorer
    Mar 26, 2022
    From my own personal experience that is very typical and don’t forget there are probably some small things running in the background
  • time2roll's avatar
    time2roll
    Nomad
    Mar 26, 2022
    LFP has a resting voltage that is lower than the charging voltage. The observation is normal.
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Mar 26, 2022
    The charts I’ve reviewed show a lithium battery to be at 100% SOC with 13.6 volts resting.
  • RolloMartins's avatar
    RolloMartins
    Explorer
    Mar 26, 2022
    time2roll wrote:
    LFP has a resting voltage that is lower than the charging voltage. The observation is normal.


    So the batteries are still considered fully charged?
  • time2roll's avatar
    time2roll
    Nomad
    Mar 26, 2022
    Yes. Anything about 13.4+ is fully charged if the battery was brought to 14+ volts.
    The voltage curve is very flat from 13.4 to 13.0 volts and contains about 80% of the energy.

  • Sandia_Man's avatar
    Sandia_Man
    Explorer II
    Mar 27, 2022
    That is ideal as you don't want to indefinitely charge batteries at 14.2 volts, modern converters/inverter chargers have multiphase charging capabilities and will start with bulk phase where highest charging voltage is noted. Depending on how depleted your battery bank is it could take some time to fully charge, when voltage drops to around 13.5 volts more or less indicates battery is charged and is currently in float phase.
  • pianotuna's avatar
    pianotuna
    Nomad III
    Mar 27, 2022
    In an ideal world Li would want to be charged to 100% once a month.

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