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My 75/15 solar charger seems to go to Float too early, the BMV is telling me 80% SOC.
Could the battery be fully charged already & the BMV is not correct?
I should add, the battery is 300AH LifeP04 & charger settings to suit.
Screenshot_20210911-122303.pngScreenshot_20210911-121726.png
The system does NOT use SOC to change charge states, all chargers use voltage and thus the MPPT also use's voltage and from your pictures you are reaching 14.23 volts and the mppt unit will then switch from bulk to absorbtion for 1 hr and hold that voltage then go to float (depending on battery selection settings), If you are unsing a BMV battery monitor then under battery settings in that unit change the charged setting to 14.1 volts and then the SOC will reset to 100% when ever the voltage reaches 14.1 volts
Voltage shown on BMV is only 13.15v & 83%.
Never seems to reach 100%.
so check why there is a difference between the battery connection on the mppt and the voltage at the battery.
maybe small wires , bad connections etc etc
13.12v @ BMV700
Your battery is getting to 14.23 volts as per the Smartsolar, so you need to work out how. also why was there a hi of 15.20, Maybe your batteries BMS is turning off, and voltages are then spiking, there is nothing more I can suggest but you need to do the voltage test when the battery is at 14.2 volts
you are also draining the batteries very deeply as well as they are going down to 11.98 volts at times. I am presuming you are using lifepo4 . so also if the battery cells are unbalanced and the bms is turning off because one cell is over voltage, then this will trigger a hi voltage as well.
So check the system when its up at 14 odd volts and see why
Again today the charger has gone into Float as it reached 14.6V at some point (battery setting).
The Battery at the terminals is only 13V, same at BMV & only 73% SOC.
After watching the charger go through all stages of charging today I think I have the answer & solution.
The charger runs in "Bulk" untill the charger gets to the 14.6v Absorption setting & continues at that rate for 2 hours thereabouts.
Unfortunately due to the voltage drop through the 6 metre cable from the charger to the battery, the charge rate is only 13.11v so not really getting a good charge.
After the Absorption phase the charger goes to Float & runs at 13.6v which is only 13.1v at the battery so does pretty much nothing else all day.
This is the final voltage for the day & only gets the battery back to around 80%.
Solution:
Instead of changing the settings to compensate for the losses which could overcharge the battery, I will move the charger from the solar panel & position it next to the battery with minimal length cable.
This way the charger will deliver what it should & extract more from the solar panel, at present the power from the panel is being throttled back as it's seen to be not needed.
