I’m considering a small battery backup for a router and fibre ONT. Before asking Grok to compare options, I want to make sure I’m giving it numbers that support a useful runtime estimate.

The router’s adapter says 12 V, 2 A, but I don’t have a measurement of its actual power draw. Some battery listings advertise mAh without making the voltage obvious; others list watt-hours. I’m also comparing a DC backup unit with an AC power station that would use the existing adapters.

For battery backup runtime estimates, what should I measure or collect first? Should I ask Grok for a range under different loads rather than one runtime figure?

I’d also like it to check DC UPS compatibility separately from capacity. Which connector, voltage, polarity, and output details need to be explicit before a recommendation is worth considering?