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I had an underpowered battery backup for my desk, and was using it for my gaming PC, two laptops, and two external monitors, and all my peripherals. (It didnt o
by digitalsushi 2y ago
I had an underpowered battery backup for my desk, and was using it for my gaming PC, two laptops, and two external monitors, and all my peripherals. (It didnt occur to me I was overrunning it, otherwise my rant here is nonsensical)
The monitors both had the same general issue - they would fail to find a signal every few weeks, and I'd find that waiting a few hours with them turned off would help.
I have pages of notes here. Another way to get them to work would be booting up the windows computer, which would seem to 'trick' the monitor into getting a signal on hdmi, and then I could switch to display port for the mac laptops to be used.
Anyways it's all crazy rambling notes, with copious timestamps, looking for patterns. I have an IR heat thermometer from the kitchen and my monitor vents would regularly have air over 160F coming out the tops when the monitors would not even post the vendor logo after a hard power reset.
I removed the battery backup and it's been months now with zero blips. So the only obvious takeaway I have is that overrunning a battery is a completely worthless endeavor.
- lmpdev 2y agoWhat I find insane is the peak current discharge those little 12V 7-9ah backup batteries can push out Well over 100A for a few seconds Lithium can’t even do that in a single cell (but in turn is infinitely better for continuous current) It sort of baffles me intuitively that an extremely simple lead battery can for a short while compete with the grid
- jpgvm 2y agoYeah this is why lead acid was hard to replace in cars with lithium chemistries. The Cold Cranking Amps (pretty much the peak startup current) that they can provide is rather insane. Even my small motorcycle battery provides over 250 CCA.
- elintknower 2y agoSuper capacitors / just large capacitors in general might eventually save the day here. The only issue is super capacitors can't generally bake in the heat all day and still work for 3-5 years like lead acid batteries can. Supercaps is how "fast" charging in most smartphones works as well since they can soak current faster than the battery itself and also mitigate cycling batteries too hard.
- jnsaff2 2y agoIt won't be anywhere near 12V while supplying those 100A.
- p1mrx 2y ago12V x 100A = 1.2 kW. A typical grid connection for a house is 240V x 200A = 48 kW.
- somehnguy 2y agoLithium polymer pouch cells can easily push out well over 100A, even relatively small cells hit this mark no problem.
- russdill 2y agoAre they Asus monitors by any chance?
- digitalsushi 2y agoboth dells. different series but both dells.
- russdill 2y agoAh, there was a line of ASUS monitors that were notorious for bad caps and when conditions were marginal, they'd take forever to get a signal.
- j45 2y agoIt might also be helpful to ensure you have a battery backup that provides pure-sine wave electricity when plugged in, and ideally as close to it as possible when on battery backup and the power is out.
- jjeaff 2y agomost electronics don't need pure sine waves as they are converting the ac to DC anyway. but perhaps a square wave could throw off some PSUs.
- j45 2y agoGood point. I ran a lot of gear through a decent separate PDU and the rack of datacenter gear refused to die. No burst transistors or other things that can be the norm after. My comment was definitely based in this - providing the cleanest electricity possible, however, doesn't hurt, and can only help.