4.6. Estimating charge time
A lead acid battery is at approximately 80% state of charge (SOC) when the bulk charge stage is completed.
The bulk stage duration
T
bulk
can be calculated as
T
bulk
= Ah / I
, where
I
is the charge current (excluding any loads) and
Ah
is
the depleted battery capacity below 80% SOC.
An absorption period
T
abs
of up to 8 hours may be required to fully recharge a deeply discharged battery.
For example, the charge time of a fully discharged 100Ah battery when charged with a 10A charger to approximately 80% SOC is
T
bulk
= 100 x 80% / 10 = 8 hours.
Including an absorption duration of
T
abs
= 8 hours, the total estimated charge time would be
T
total
= T
bulk
+ T
abs
= 8 + 8 = 16
hours. A Li-ion battery is more than 95% charged at the end of the bulk stage and reaches 100% charge after approximately 30
minutes of absorption charge.
Phoenix Smart IP43 Charger
Page 13
Operation
