Replacing your alarm system battery is a fairly straight forward process, but security system companies like to charge a fortune for it. Essentially all you need to do is open the main panel, remove the existing battery, fit the new one in the exact same way, and close the panel.
Its important to be aware that the panels are almost always fitted with a tamper switch, so unless you know how to disable the tamper switch before opening the panel be prepared for the siren to go off. Normally entering your security code will silence the alarm but this may not always work.
It would probably be best to let your neighbours know that the alarm may sound for about a minute a get yourself some ear plugs.
