Steelphase spo1 battery

Hi fellow members, i have just returned from nine days in the leonora area. The weather was really good but the flies were something else.
My spo1 developed a liking to not holding a charge, so after switching on my detector i was blessed with about ten minutes of decent detecting time before it shut down . I have allways charged my batteries on the first of every month but may have to do a rethink.
I have contacted NENAD and sent my spo1 to him for a new battery. Has anyone else had any battery issues with the spo1. New season
is here so all the best to everyone. cheers ron.