AFFZP0BB – ACE3 – User Manual Page – 81/139
8.10 Battery-charge detection
During operating condition, the battery-charge detection makes use of two
parameters that specify the full-charge voltage (100%) and the discharged-battery
voltage (10%): BAT.MAX.ADJ and BAT.MIN.ADJ.
It is possible to adapt the battery-charge detection to your specific battery by
changing the above two settings (e.g. if the battery-discharge detection occurs when
the battery is not totally discharged, it is necessary to reduce BAT.MIN.ADJ).
Moreover, BDI ADJ STARTUP adjusts the level of the battery charge table at the
start-up, in order to evaluate the battery charge at key-on. The minimum variation of
the battery charge that can be detected depends on the BDI RESET parameter.
The battery-charge detection works as the following procedure.
Start-up
1) The battery voltage is read from key input when the battery current is zero,
that is when the output power stage is not driven. It is evaluated as the
average value over a window of time, hereafter addressed as Vbatt.
2) Vbatt is compared with a threshold value which comes as function of the
actual charge percentage; by this comparison a new charge percentage is
obtained.
3) The threshold value can be changed with the BDI ADJ STARTUP parameter.
4) If the new charge percentage is within the range “last percentage (last value
stored in EEPROM) ± BDI RESET” it is discarded; otherwise charge
percentage is updated with the new value.
Operating condition
Measure of the battery voltage, together with the charge percentage at the time of
the voltage sampling, give information about the instantaneous battery current.
1) The battery voltage is read when the battery current is not zero, that is when the
output power stage is driven. Vbatt is evaluated as the average value over a
window of time.
2) Vbatt is compared with a threshold value which comes as function of the actual
charge percentage; by this comparison the current provided by the battery is
obtained.
3) Current obtained at step 2 integrated over time returns the energy drawn from
the battery, in Ah.
4) Charge percentage is dynamically updated basing on the energy from step 3.
Threshold values for the battery charge can be modified by means of
BAT.MAX.ADJ. and BAT.MIN.ADJ. as to adapt the battery-charge detection to the
specific battery in use.
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