you can not tell anything by the battery meter, like that.
you will need to read the batteries voltage at rest and at full lift hydraulic stall, both when first off charge (maybe 15 minutes of operation) and when the truck's meter starts to drop.
then we will get you to read each cell's voltage and Spec Grav.
in real life, a 5 or 6 hour operational shift per 24 hours (with 8 hours charge and 8 hours cooling off) is about all that can be expected with a nearly new battery. It might be worth noting also that just because a battery tested "good" yesterday, is no reason to be sure it is good today.
ALSO, when you say "the battery volts are still ok" how do you know they are "ok" and what is"ok" to you?