CPE Division G Inc. 2011 One of the most preventable causes issues with a UPS is with the batteries themselves. The UPS batteries, though they can typically be installed with parallel strings, are normally a single string of batteries wired in series.  This means that one “2 or 6” cell battery if fails, will open the circuit, rendering your critical load suseptible to failure.  These batteries are typically rated for between 3 to 5 years life expectancy, however certain environmental factors to affect the over over life.  Temperature can play a large part in pre-mature aging of batteries. Regular Preventive Maintenance is recommended, in which testing methods conducted can assist with detecting signs of battery problems or their potential to fail.  Recommendations will be made dependant on each situation, and if the option is to replace the batteries, CPE will supply the best high quality battery to suit your application. As stated, these batteries have a typical life expectancy and should be replaced within these timeframes to ensure the most reliable protection for your critical equipment. For quotations on battery replacements or to have one of our field service technicians schedule a check of your system, please contact us and we will be more than happy to assist you.