Optima xm alrm bell sounds every time there is a power cut ?

My new home has an optima xm alarm system installed and we are experiencing issues when there is a power cut as the bell starts to sound. I think this is when the power restores but I could be wrong. It has usually occured during the night when i have been half asleep still, i have to re enter security code and all ok again. My understanding is there is a battery that should take over in the event of a power cut? I assume this battery could need replacing as our house is about 13 yrs old and I have no way of telling if this was ever replaced. Is this a difficult job that requires engineer or could it be done by myself. Also is there anyway to stop the bell sounding without replacing the battery in event of a power cut? I heard you can remove the fuse spur that is located next to alarm box?