The inverter batteries are degradable items, meaning they lose their power as time passes away. The lifespan of a battery typically varies from 2-4 years which depends upon how aggressively it has been used.
If you already bought an inverter & battery a few years ago, most probably it’s time to replace your battery. Or maybe you are willing to buy an inverter & battery for the first time.
By the way, whatever be the reason, if you want to buy an inverter battery, you should first read this comprehensive review cum buyer’s guide so that you can better understand what are the most significant parameters you must consider before buying the best inverter battery available in India.