Imagine two businesses asking for a battery quote in the same week. One runs a cold storage warehouse. The other runs a data centre. If both receive the same standard proposal, at least one of them will end up with the wrong system.
A backup generator takes time to spin up. Not much, usually under a minute, but enough that a factory floor sits dark and idle right when it matters most.
Ask ten suppliers if they "manufacture" batteries in India, and nine will say yes. Push a little further, ask where the cells actually come from, and the story changes fast.
Picture a cold storage facility mid-shift, power cuts out, and the diesel genset takes eleven seconds to kick in. Eleven seconds is nothing on paper.
Why does a two-year-old laptop suddenly need charging by lunchtime when it used to last a full workday?