[brian_]

Unfortunately, I haven't a clue what their capacity is; everything I know is printed on the label.

I didn't really expect too much out of them; just that if they could run our data center with dozens of 400-1000 watt servers for 25 minutes then it should be able to run the house for a couple hours...

I do need to figure out the pack capacity though - based on the info displayed on the sticker, is there a formula to figure out how to convert from "284W/cell 15min" to Amp-hours/kilowatt-hours?

Well, the label says 284 W/cell for 15 minutes, which with 6 cells/battery would be 142 amps @ 12V for a quarter of an hour, or 35.5 amp-hours per battery at a 4C discharge rate. That's 284 W/cell * 6 cells *0.25 hours = 0.426 kWh each. The set of 72 of them should then deliver 123 kW for 15 minutes (and half that for half an hour).

that's not so difficult to find... 70AH / 8hr

https://www.sure-power.com/wp-content/uploads/2014/07/DataSafe HX.pdf

Yes, at an 8-hour discharge rate (C/8) they're 70 Ah each... as expected, much higher than the 4C rate. The 20-hour (C/20) capacity would presumably be even better.

At this slow rate, energy capacity is nominally 70 Ah * 12 V = 0.840 kWh each, and the average discharge power over 8 hours would be about 100 W each. That's 7,200 W for the whole bank to power the house, which is a lot for a house... good, because my guess is that you don't really want to discharge to 1.75 V/cell if you can avoid it.