Any recommendations for a cheap really fat (long runtime) UPS? Maximum runtime or is it J, or C, per £. Not going for max current delivery. Basic, no shutdown notification i/f required as it isn't for a server.
I'm sure I've asked about this before but just I can't find the thread. I was asked to try and evaluate the current draw, on which I failed. It will be three dsl modems, one low-power Firebrick router, one HP 24-port switch, one or two WAPs. Iirc we might have tried to do some guesswork.
Second issue: I'm wondering if I should partition the whole lot into two groups supplied by two UPSs. Instinct says 'no' because of unequal usage of the UPS. But I'm the other hand I could keep the modems alive longer than everything else so as to avoid upsetting DLM by letting the modems go offline. (If you believe in last-gasp awareness, then this is a non-issue.) Having multiple UPSs might be a desperate way of getting more runtime, but again it represents uneven usage. Also I don't know how the runtime vs current works, nor how the J / C / runtime vs £ economics work, whether getting twice as much runtime costs you more or less than twice as much money when purchasing a fatter UPS.
A really stupid idea (rule out, sanity-check). Would it make any sense at all to have one UPS driving two or more UPSs in turn? This daft cascade idea gets rid of the unequal usage thing but presumably the wastage due to double power conversion inefficiencies is stupid and just wastes the root UPS, or even worse, completely overloads it.