UPS for ReadyNAS 6 + ReadyNAS Duo

Thanks for all this info PapaBear, very useful stuff. Your dedication to protecting your system makes me feel a bit crazy for having let this slide for so long!

Finally some real numbers to work with. Sounds like the numbers for your pair of NAS devices are not too far off what I should expect for mine.

The total load according to the front panel display is 116W or 13% of the capacity and has an estimated run time of 48 minutes.

Ok, so far I'm with you - this is with your BR1500G which I believe is 865W right?

So, I would estimate that a 700W unit would provide less than 24min run time even without the laptop.

Whoa, you lost me now. So a 19% reduction in your wattage results in a 50% reduction in run time? I guess this means it's not a simple linear function here?

The 1350W unit would provide about 40 minutes.

I'm lost again. Did you actually mean to say 1350W here or are you referring to the model number? I can't seem to find a BR1350G anywhere - but I can find a BR1300G at 780W - is that what you are referring to?

Ok, so I can't really see how your math works here. I've plotted the 3 estimates you provided, assuming we have:
116W / 865W = 13.4% => 48 mins
116W / 780W = 14.9% => 40 mins
116W / 700W = 16.6% => 24 mins

This seems to be a downward sloping curve (rather than linear), and if I'm right, that puts the estimate for a 540W UPS (such as BR900GI - £156) down to below 5 mins, which I guess isn't going to work. If this was simple linear math, I would calculate that 540W should still give us enough for about 30 minutes (i.e. 62% of your 865W).

The other options I can see on Amazon UK are BR1200GI (720W) for £230 and BR1500GI (865W) for £270. So I guess I could pay the extra £40 for future expansion capability plus get the extra 145W which can cover an extra switch/laptop/etc. But this is quite a bit beyond what I was thinking to spend. Is the math here all correct?

I was really hoping to spend £73 on a simple BE700G-UK (405W), but now with these numbers, it sounds like that isn't even going to come close to what I need.

I'm tempted to go ahead and get that cheaper one anyway, give it a try, and if it definitely doesn't work for the NAS, then move it into the other room and use it to protect the routers and other stuff.