Comment on DC UPS for router?
povoq@slrpnk.net@slrpnk.net 2 weeks ago When charging, 12V lead acid batteries have significant higher voltages (>14V), so you basically need a DC to DC converter to make sure you get a stable 12V supply. Some (typically industrial/automotive grade) systems have that built into their internal power supply and can work directly off a 12V battery, but with consumer routers I would assume that not to be the case.
moonshadow@slrpnk.net 2 weeks ago
Hey, I have a lot of appreciation for the infrastructure you maintain so don’t take this the wrong way: you’re very confidently overcomplicating this one all over the thread. People run nominal 12v stuff direct from battery all the time and it’s fine. It’s the norm in RVs, boats, and off-grid housing. There’s usually quite a bit of wiggle room. The router I’m using right now won’t actually cut out until ~8v and sees almost 16 during my ancient lead acid battery’s eq cycles. It’s completely fine and has been for years. Not industrial or automotive grade by any means, a low-end Netgear from the thrift store.
You also state “while there is DC power the battery in a UPS isn’t used”. Assuming you mean AC that’s still not quite correct, it’s always being charged at least a little and tapping it for DC is perfectly fine.
That’s my advice to op, and a setup I’ve run before: replace the 12v battery attached to their existing UPS and wire the router/any other 12v devices right to it. A UPS is just a nicely packaged battery charger/inverter/transfer switch. Wiring them to larger/cheaper batteries that don’t happen to fit their casings is also entirely viable, as is running either of their outputs to a load panel. Sky’s the limit :)
Right AC. Was a typo, corrected now.
As for running nominally 12V stuff directly of a battery… you got lucky with your router then. Ihad the same idea with various mini PCs and ARM SBCs, and the majority absolutely should not be run directly off a battery where the voltage fluctuates so much.
moonshadow@slrpnk.net 2 weeks ago
I haven’t had access to grid power in over 10 years and am pretty familiar with this stuff as part of day to day life. I do now have solar. Really don’t think me and everyone else I know have been getting this consistently “lucky” for this long across such a wide range of devices. The 11-15v a nominal 12v battery system normally experiences is not a huge amount of fluctuation, and I have yet to encounter a 12v device that couldn’t take it. On the contrary, I’ve tried much dumber stuff and gotten away with it. There’s a 9v piano keyboard and a 19v computer monitor wired straight into that same battery. The only time I’ve actually killed something is by reversing polarity. Voltage too low=won’t turn on, voltage too high=gets hot, and all these years of wiring up random scavengings to see what happens have taught me most gear is surprisingly tolerant/resilient