well have not had any issues with inverter batteries. they usually die after 2.5-3 years of usage. but on my ups at least i have received a replacement within a day of confirmation that the battery has developed faults. i guess inverter batteries are different from ups batteries (mine uses a smaller 65ah units). so i could be entirely wrong. reminded me. i should call the exide guy anyway reminding him about the two replacements that are to be delivered today!