Pride Go Go Ultra 4 Wheel Travel Scooter "having battery problems" Questions

I have a Braun ThermoScan Type6013 have changed batteries twice but keeps coming up LO when try to read a temperature, any ideas? Problem: Temperature taken is not within typical human temperature ...

victory 4 pride mobilty scooter,the charger dont seem to charge up the batterys. is the charger faulty. the scooter when fully charged gos realy well .tried to charge up my scooter.but the chargr wont