Battleborn butteries (with Bluetooth) shown 100% sog on battleborn app and 26% on VRM. After I plug into shore power- multiplus start pushing 1400w to the battery bank (4 battleborn batteries each 100ah). Battelborn app still show SOG 100% but also about 250w per battery charging…
I would lean towards trusting VRM. I assume VRM is making this determination based on data from a properly configured shunt. Not sure why the Battleborn app would be inaccurate and I honestly don’t have any experience with it. Perhaps update it or uninstall, reinstall and re pair with the batteries. I would always trust a properly configured Victron Smartshunt or BMV way before the internal shunt in a “smart” battery.
However, assuming a common LFP charging algorithm, LFP batteries will take amperage all the way to the end of the absorption cycle, with amperage decreasing as voltage increases. If you see this happening then they are not full.
Bulk charging will occur any time the battery voltage is below the absorption set voltage(in other words “not full”). For example, let say the absorption voltage programmed in the charger is 14.0V, if the battery voltage is at 13.5 the charger will charge with its full available amperage(30amps for a 30 amp charger). As the batteries reach full charge(the programmed absorption voltage) a properly configured charger will go into an absorption stage for a set period of time. In this stage the voltage will stabilize around 14.0-14.4, depending on the programmed algorithm, and the amperage will slowly decrease. Regardless of the bluetooth app this is how a lithium cell will charge with a properly configured charger.
Of course there are many factors that could be at work here but I am going on the information you have given. In short, if the batteries are indeed full you will see a voltage of around 14.00 or more with very little amperage during charging. Low voltage and high amperage likely indicates bulk charging and a “not full” battery.
This mismatch almost always comes down to the shunt settings rather than a faulty battery. The SmartShunt only resets to 100% when it actually sees the charged voltage with a small tail current, so if the MultiPlus never finishes absorption (or the charged voltage setting is a touch too high), the VRM reading drifts down over time while the Battleborn BMS snaps to 100% as soon as charging starts. Check the shunt’s charged-voltage, tail-current and charge-efficiency settings against Battleborn’s recommended values, and let the bank complete one full absorption charge so the shunt can resync. Also double-check that every negative lead runs through the shunt, since any load or charger bypassing it throws the count off.
You don’t have a multimeter (if not, get one and thank me later)? You could measure the voltage manually and compare with the apps.