The charging time depends upon a charger.
As a standard, there are 8 hrs, 10 hrs, 12 hrs chargers.
If you work on shifts, yo use the 8 hrs charger, but the praxis we have here is that the truck is used till the red light on discharge indicator flashes. Than the battery is exchanged, sometimes in the middle of the next shift.
Usually for shift work, two batteries are a standard set.
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