Damage/age usually shows up as taking less and less mah. They also put out less mah as they age. I haven't seen that the voltage declines in mine as well. They charge normally, just charge less.

Chargers voltage measurement is a quality issue and how well the charger was calibrated on assembly. Be happy its on the low side and not trying to overcharge. There's a recal procedure on the Accucel chargers - I don't know if that is applicable to yours or not.

You might call Venom and see what kind of answer you get from them?