Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit 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.

1
vote
0answers
63 views

MOSFET N channel switch with Raspberry

Dear electrical engineer, I'm working on a project using an UPS(Uninterrupted Power Supply) with a Raspberry PI, an USB power 5V in and a 3.7V Li-ion battery. My goal is to turn ON/OFF the ...
0
votes
0answers
40 views

Problem with driving inductive loads with inverter

Newbie here. I've got this old line interactive type UPS which cannot drive any inductive load. I suspect the issue is with inverter side of the cct as there is no issue when the commercial supply is ...
1
vote
0answers
34 views

TP4056 with DW01, can I use a diode to create an “UPS”? Design review

I'm studying lithium cells and their related mainstream modules. One of the most common -yet wrong- use of the TP4056 module is to use it with the USB 5V input and an active load on the output (at ...
1
vote
1answer
65 views

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 ...
2
votes
2answers
94 views

Switch to battery when voltage supply drops certain threshold

I have made this circuit but can't quit make it work. Vext is my main supply from a car (9 - 14V) Vbat is 8 AA batteries (10 - 13V) Vout supplies power to a SMPS As it is now, supply "fades" between ...
0
votes
1answer
65 views

Transformer mains identification

A friend gave me a transformer from an APC UPS that supposedly was capable of \$1300 VA\$ (I have my doubts, but it is very large and I am not going to be using nearly so much power, so OK). He doesn'...
1
vote
1answer
80 views

APC Smart UPS - 2700uF 40V Capacitors

Please excuse the possibly simple question but this is all a bit new to me. I have an APC Smart UPS 1000 which has a very large/tall 2700uF 40V capacitor on the battery (24V) connector. Not knowing ...
0
votes
1answer
64 views

Calculate VA of device 100-240v

Firstly I apologise for any mistakes this is deifnitely not my field of expertise. I also apologise if this is not the right place for this question. I have been doing some reading regarding sizing a ...
0
votes
1answer
59 views

Variable output from Power Bank (24W = 12v * 2A and 5.4W = 9v * 0.6A)

I started with trying to find 2 UPS for 2 of my routers with the following input specifications: 12v 2A 9v 0.6A I realised that buying 2 power banks will be economical than buying 2 UPS for the AC ...
0
votes
0answers
45 views

“lithium for buffered usage in UPS”, or floating-charge lithium accumulator

For lead acid there are typically two paradigms of charging (or use-scenarios). First one is deep cycles, when you exaust 40-60% of capacity (not less than 12.4V), then charge it to 14.4 with ...
0
votes
2answers
63 views

Sealed lead-acid battery UPS indoor?

I bought a BX700UI APC UPS for my linux arm server setup (40 watts) to protect it from power cut. - I have the server in the bedroom is it dangerous to have such an Ups in a small bedroom? - Thinking ...
0
votes
2answers
77 views

The output of a boost converter doesn't stay at 5 V

Let me start by apologizing for my english in advance :) I'm trying to build an UPS for my raspberry Pi (even though I have basically zero experience in electronics). When the power cuts out, I want ...
0
votes
1answer
107 views

(inverter repairs) Does reverse polarity can kill power MOSFETs in UPS inverters? [closed]

I had an old computer UPS (almost 7 years) and I modified it to use external battery (a 12 Volt motorcycle battery) since the old 12 Volt battery is completely dead and no replacement is available for ...
3
votes
1answer
113 views

Integrated 5V uninterruptible power supply (UPS) with a lithium cell?

I'm trying to figure out the best way to implement a UPS for an embedded system that runs from a 5V supply. Essentially the system has a 48v to 5v, 1.2A output DCDC converter that powers my system. ...
0
votes
2answers
64 views

Cap maximum wall outlet voltage

I live in a rural area. A problem occured when my UPS could not run my computer simply because of voltage fluctuations. I have tried many stabilizers but its too rapid that it would make a tick and ...
3
votes
1answer
110 views

5v power switcher: Uninterruptable power source

I know there are a few other questions similar to mine, but after looking through the answers, it does not seem like it's what I need. I've also looked at the Arduino Due/Uno circuitry, and they aren'...
2
votes
1answer
116 views

5-10 second backup for wifi router during power cut

In India power cut is often. And most houses are installed with Inver-battery, for backup till the power comes back. But since all inverters don't behave as ups, there occour a little gap between the ...
1
vote
1answer
123 views

How to add an UPS beeper volume controller so that I can make it sound quieter when it beeps?

I've an EATON 5E850iUSBDIN 850VA/480W UPS. This UPS makes a very loud beep sound both when it's first plugged into the mains(short beep) and when it's first turned on from the button(3x longer beep)...
0
votes
1answer
79 views

How to protect equipment from voltage anomalies

My refrigerator makes some short anomalies in electric network in my apartment whenever it starts/stops its compressor. I'm not sure if it's a brief frequency change or voltage drop. I can notice this ...
1
vote
1answer
215 views

Can I replace rechargable batteries with (super)capacitors?

I need a very small UPS just to give an embedded device time to shut down when power is lost. There are a variety of solutions that use LiPo batteries to provide extended runtime; they typically take ...
0
votes
2answers
48 views

Uninterrupted power switch for 240V

I need to switch supply power from one source to a different one without losing power. I am designing a control system for a customer to run an induction heater. They want to run the system off a ...
1
vote
3answers
78 views

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 ...
0
votes
1answer
213 views

Two 5V Raspberry Pi UPS Idea

I need a cheap, reliable and easy to build UPS for my raspberry pi server. The UPS must maintain power for a maximum of 1 hour. Based on what I found on the internet,I came with two solution. (see ...
0
votes
1answer
72 views

Lead Acid battery switching regulator to keep constant output

I am trying to use this ups design(below image)(max 500mA) but I want to use switching regulator instead of linear regulator to keep regulated Vout as constant possible even when battery drop below ...
-2
votes
1answer
109 views

12/24VDC to 240VDC Circuit For a UPS

I need to build a circuit to step-up 12vdc or 24vdc to 240vdc and have a current rating of at least 50A. I got this really expensive UPS from someone but it takes a 240v battery pack which I don't ...
1
vote
1answer
54 views

UPS for 1.1kW system [closed]

We have 3 motors each 0.37kW, they are now running on mains power, sometimes mains power cutoffs/fails, in that case we want the motors keep running. The motors are controlled by a PLC which do not ...
0
votes
1answer
136 views

Mini UPS schematic question

I found the following schematic for a rudimentary mini UPS: (Original source website) and in the description on the original website (link above) it says: D2 → Prevents backfeeding of 5v wall ...
0
votes
0answers
21 views

Can hard wired ups be wired to IEC60309 plug?

So I've seen some pretty good deal on 6000va ups. The thing is, those ups are required to be hardwire into the circuit. But I may want to move them around maybe even once every few months. And I don'...
0
votes
4answers
770 views

5s backup by 1F 5.5V Super Capacitor

Can I have about 4 to 5 seconds backup by 1F 5.5V Super Capacitor? Power supply output voltage: 5v 600mA I need 5v 0.5A for my system. I want to use it as ups for only 4 to 5 seconds so I wasn't ...
0
votes
0answers
307 views

How can I design a 12V DC UPS circuit using NMOS?

I have an NMOS with me so I tried to design this 12 V DC UPS circuit after looking at another similar PMOS circuit, but when I open the dc switch, the output is 18kV!! What is the problem with this ...
0
votes
1answer
152 views

5 seconds power supply backup for 12V 0.5A router

My country has a problem with the mains electricity supply, which cuts off and comes back straight away. My router restarts every time that happens. What I like to know is: What would be the most ...
0
votes
1answer
27 views

Is it possible for an intermittent load to draw too much current from a charger that is also connected to a SLA battery?

Planning on this setup as a 12V supply and backup: Load connected to 12V 100Ah SLA Battery connected to a charger (Residential Gateway UPS). Continuous load will be minimal (<0.5A), with an ...
1
vote
2answers
262 views

Replace DPDT relay with Mosfet?

Currently I have this UPS power setup for my Router with the help of a DPDT relay so that the router works when mains power supply fails. The working principle of my project is real simple. Two ...
2
votes
2answers
162 views

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 ...
0
votes
1answer
63 views

UPS specifications [closed]

In a UPS specication, in Input data section, it says current consumption is 18.6A maximum? What is the meaning of this? I am using a DC power supply before this in my circuit. Is it that the size of (...
1
vote
2answers
485 views

Unstable 11-13.8 volts to 12v regulator. DC-DC buck or Zener diode, how to do it better?

I have 12v power source Mean well PSC-60A with UPS function and acid buttery. In datasheet says, that output can be regulated from 12-15V - but it's not true, because tested results for output was: ...
-2
votes
2answers
354 views

Super capacitor in UPS system instand of battery

I got an idea to use super capacitors in UPS system like battery replacemant. I have UPS what give me 220V/2000W what use 3 batteries 12V/7,2A. That UPS power whole my office (lights, computers, ...
1
vote
1answer
345 views

P/N mosfet and Ideal Diode, how does this circuit works

This is what I found in http://durdoor.com/bin/ideal-diode when I search up some Li battery charger and UPS (Uninterruptible Power Supply) circuit. I realize Q3+Q4 makes an ideal diode (for battery ...
0
votes
1answer
51 views

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.
0
votes
1answer
391 views

Can one battery bank be connected to two static UPS devices?

To make a redundant static uninterruptible power supply (UPS) configuration such as pictured below, I have seen warnings in UPS manuals that each UPS is to be connected to its own battery bank. But ...
-1
votes
1answer
460 views

Why does my UPS click and beep continuously? [closed]

here where I live there's a lot of voltage fluctuations ( it can't be helped. ) so I bought a ups ovislink cobalt 1000+ ( 1000va) ( line interactive it has an AVR ) ok it works perfectly except it's ...
0
votes
2answers
366 views

Can grid-tie inverters charge UPS batteries if connected to the UPS output?

If you have a UPS powering some load in an off-grid situation, and you have a solar panel with a grid-tie microinverter, is it possible to connect the grid-tie inverter to the UPS output, such that ...
1
vote
2answers
212 views

Y.S. Tech Fan 4 wires, but which is which?

I've a Y.S. Tech fan with 4 non-standard colored wires connected in a UPS, and I want to replace that fan with a bigger standard 4pin fan doing a "UPS case mod". Motivations aside. Here I want to ...
1
vote
2answers
333 views

5V UPS circuit with NiMH joule thief backup

I'm trying to design a UPS circuit for microcontroller backup. Require 3.7-5V, and less than 50mA for 10 seconds every 15 min. Power cuts in my area are never longer than 3hours, and occur rarely. I'...
4
votes
2answers
166 views

Unknown smd device from ST replacement possible? [closed]

first time here I would like to ask what is the blown up device on the picture. I think its somekind of diode. I searched the ST site, but I didnt find anything with these markings. The board is from ...
8
votes
3answers
515 views

5V ups circuit oscillating?

I'm trying to design a 5V UPS. Power to load should switch if line voltage falls below about 4V. Battery voltage may be from 3.8 to 5V. I'm simulating in LTSpiceIV. I'll be using mosfets to supply ...
0
votes
1answer
85 views

How to UPS-protect this “dual source” setup? [closed]

I'm analyzing how to best protect a setup comprised of a NAS/Router/Wimax from power surges. A very simple diagram is this: When I write "dual source" (term which I just invented) I mean that the ...
0
votes
0answers
319 views

Bypass battery of UPS

I have DC-UPS http://www.mercury-pc.com/product-detail.php?link=p-ups&subtitle=UPS&productid=1255 I want to make this ups bypass battery(by using a switch), the switch connect and disconnect ...
0
votes
0answers
117 views

Blown varistor after connecting UPS?

I have a pellet burning stove and the manufacturer provides for two options for battery backups. One is an inverter and deep cycle battery that can run the device for a few hours, the other is a UPS ...
1
vote
1answer
109 views

Is my laptop charger is working as harmonic filter and absorbing harmonics?

I have a square wave backup inverter (UPS). Whenever the power goes out, UPS turns on but all the fans run with noise and humming sound. I know it is because of square wave and harmonics. But when I ...