Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [ups]

A UPS is an Uninterruptible Power Supply that provides backup power when the main power source is lost. Questions on repairing commercial ones are generally off topic.

A UPS typically has an AC to DC converter at the input, followed by a battery charger and batteries, and a DC to AC inverter at the output.

When the main AC power source is lost, power is provided to the attached device(s) via the batteries and inverter. When power is restored, the battery is recharged to be ready for the next power loss event.

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Raspberry Pi UPS with 18650 + TP4056 + MT3608

I'm trying to make an UPS for my Raspberry Pi 3. Based on https://nomadaselectronicos.wordpress.com/2015/05/22/fuentecargador-con-carga-compartida-load-sharing/ and http://ficara.altervista.org/?p=2736 I ended up with this: In theory, it should…
vazquezjm
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Can I add batteries in parallel to my UPS to get longer run time on battery

I have an uninterruptible power supply which powers my PC, monitor, and WiFi router. My question is: can I add a second pair of batteries to the UPS to get more run time on batteries without damaging the UPS? The second pair of batteries I plan to…
Stephen Daddona
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Why should a UPS fail if the battery fails but the power from the wall outlet is still good?

Sounds to me like a design flaw. Why wouldn't this work? No switching transient and the power supply to the servers (or whatever) fails only if both battery and AC power fail. simulate this circuit – Schematic created using CircuitLab Over the…
robert bristow-johnson
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UPS causing GFCI tester not to work

Here's an odd one. I have a GFCI-protected circuit with a Uninterruptible Power Supply on it. I've found that when I test the outlets on the circuit with a GFCI outlet tester the tester does not trip the GFCI. However, when I unplug the UPS from…
Todd1561
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UPS 5v 3A block diagram

I'm trying to build an UPS for a device that needs 5V and 3A. But I'm not sure if this block diagram (using 3 3.7v 18650 cells) is safe and would work. Can anyone give me some feedback? I hope my writing is clear enough.
GB5
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Surge Protector Life Span

I work for a small office that is relocating. Recently all new computers have been purchased for staff. In preparation for the move, I noticed that virtually all the surge protectors in the office seem probably older than 10 years. Is there a surge…
mdn
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Operating a fan on UPS

A short, useless intro to the question, feel free to skip it: I had a power outage in my home yesterday. Power outages aren't what they used to be - Back in the day, it rendered me completely unable to do anything, but nowadays I have my laptop,…
user976850
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UPS battery advice

I have a APC UPS with a 9 Ah battery. Would it be ok to replace it with an 18 Ah battery? I realize that some modifications would be needed since it won't fit in the case.
fixit7
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How long will laptop run from UPS?

The laptop has input: 18.5V, 2.7A The UPS output is: 220V, 6.82A and also something about 1500AP I have no idea how to work out how long I would be able to run the laptop off the UPS when the UPS is disconnected from the mains.
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Switching for UPS battery (without time delay)

I have bought a battery charge up board as here. It provides two modes on the EN pin: 1) ground EN pin, the board will charge up the battery from 5V charge source only. 2) float EN pin, the board will charge up the battery from 5V charge source and…
MW_hk
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Fallback electronic circuit

I've got a 220 volts fishbowl pump that is conected and working 24x7. However, when a power outage happens (they happen often where I live) I need to switch to a 12 volts version of the same pump, so the pump never stops working. I can, buy 2…
Artemix
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Convert Jackery (solar generator) to use as UPS without losing battery quality

I have bought this Jackery device and I want to use it as UPS. I know that if I would connect it in between of socket and load it will act as UPS, but that will degrade the battery quickly. My question is there something I can put in between, so it…
Newbie
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More UPS batteries, more fun (and power)

I got some semi-old UPS batteries in stock and hooked them up to my Eaton S3 700VA to test it out, and it seems to work pretty well: charge, discharge and feedback from the UPS to the UPS-software (using nut), all seems fine, got longer battery…
BMWW
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Danger when using UPS with static

I just bought a UPS Neo 650A, I managed to install it and it works correctly, but I have a doubt, sometimes I have static and I usually get shocked with the keyboard or the mouse, so if I touch the power button of the UPS to turn it on or off, If I…
FGD
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Online UPS ground question

A very simple question before I purchase an online UPS. I have a ground loop problem with an audio workstation, I temporarily removed the earth (to test only) and the noise went away, so I am considering an online UPS with this PC to isolate the…
Oliver M Grech
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