A follow-up...
Backup TimeThis video confirmed a 6-hour backup:
https://youtu.be/53NcsctuxV0?t=235I imagine that, with a widespread outage and many houses also losing power, the DSLAMs will last rather longer than when the power failure is localised to just the DSLAM.
RemovalThe style I saw the other day look like they can be fixed together in a 288 ...
But they are 18kg each, so moving a fixed pack is likely to need a little help. An external shelf, to pull them out onto?
RechargeWould recharging a battery pack need to be high current? We want the batteries to be available 24x7, but after an outage, is there a huge requirement that they be instantly ready again?
At maximum, a lead-acid battery wouldn't normally want to be charged any higher than a current of (capacity/10), to prevent giving off hydrogen gas - so 55Ah would max around 5A. At 48V, that would equate to roughly 1A on mains voltage, for maybe 12 hours (though it would extend much longer, at lower current, with a decent multi-stage charger). It would actively consume around 250W while charging the bulk, and total about 3kWhr.
As far as I can make out, that's about the same power draw as 2 or 3 street lights. Or a couple of fridges. At maximum. If we're that close to the generating margin, there's probably more to worry about.
Incidentally, the 70,000 cabinets in the street don't really represent a new demand on the nation's power generators. Almost every circuit on an FTTC cabinet will have started out as an ADSL circuit on the exchange. All that has happened is to transfer the load from exchange-based to cabinet-based ... and therefore transferred the battery recharge demand from a central exchange battery (that will now need less recharging) to a distributed set.
LancasterWas there any reported outage from cabinets running out of battery?