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.

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32 views

SLA Battery Parallel Connection with PSU and Load

I'm designing an ON-Line UPS and I have some problems with battery charging. In this system I have an inverter and the power supply which can deliver the power required by the inverter, and two 100Ah ...
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39 views

Should a UPS transformer heat up on no load? [closed]

I have a ups, APC-1100BX whose transformer heats up so much that the top of the body of the UPS gets heated up too. It gets hot to the touch when there is no load. The UPS is ventilated and when the ...
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70 views

high current UPS ish design

This is my latest attempt to try building a ups ish system for my 3D printer the printer is custom-designed with 5 meters (no, it's not a typo) on each axis. we use MKS Gen v1.1 with custom marlin ...
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78 views

How does Home UPS Charge battery?

I have a pure sine wave home ups with a mains 1000VA transformer in it. Transformer is 6.7/220VAC. How does it charge a 12V battery with 20A????????? 6.7V side is connected in H bridge mosfets. ...
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30 views

Need help with terminology so that I can source a din rail version of this part

Im looking for a 12 VDC power supply that has the ability to switch to a battery when ac power is lost in addition to having some type of AC status function such as an open collector. This part does ...
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16 views

Inverter with UPS transformer

Inverter circuit I am trying to replicate the project on this website: https://electricalfundablog.com/make-simple-inverter-home-circuit-step-by-step-method/ but the recommended transformer is a 9v ...
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1answer
126 views

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/?...
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37 views

UPS power supply for both router (12V, 2A) and up board squared (5V, 6A)

I was searching for an UPS (uninterruptible power supply) to power my Up Squared Board (5V, 6A) and my router (12V, 2A). So far I didn't find something suitable but here is my idea: Take a suitable ...
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81 views

USB communication keeps disconnecting because of power dip/spike

I've got a question. I've got CNC router that's connected by USB to a desktop computer. We're in an old building, and wiring is not optimal :) I'm not an expert, but I think too many rooms are on the ...
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1answer
184 views

Help me identify power issues with this PCB

I bought the following UPS module for my Raspberry Pi: Power Pack Pro The module kinda works, when I unplug the power cable, the module instantly switches to battery powered mode without restarting ...
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2answers
41 views

Power rating of a UPS

I find it odd that manufacturers specify power rating of Uninterruptible Power Supplies (UPS) in VA instead of Watts since VA doesn't tell you how big of a load the UPS can supply. A case in point is ...
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59 views

how the battery behaves in this diagram

My question is this. I'm using this ic mppt SM72445 along with a 250 watt solar panel, mppt output configured to 50.4 or 51 volts, 12-cell lithium-ion battery pack and bms, if the load is less than ...
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72 views

how a battery behaves in parallel to the charger with a shared load but with a voltage difference

how the battery behaves in this diagram how a battery behaves in parallel to the charger with a shared load but with a voltage difference
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39 views

How to get correct response from UPS HID

I have a UPS HID device and I'm trying to use LibUSB to get data from it. The response expected is in the format below: ...
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53 views

Raspberry Pi wake-up and battery power circuit

I am working on a Raspberry Pi (3B plus) project that - at times -needs to operate on battery power, and on external power whenever available. The RPI needs to operate only when a dedicated sensor ...
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75 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 ...
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66 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 ...
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1answer
74 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 ...
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113 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 ...
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74 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'...
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2answers
131 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 ...
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83 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 ...
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85 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 ...
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58 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 ...
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2answers
75 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 ...
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78 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 ...
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170 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 ...
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1answer
161 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. ...
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2answers
67 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 ...
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1answer
142 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'...
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1answer
150 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 ...
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1answer
159 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)...
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91 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 ...
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1answer
288 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 ...
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2answers
57 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 ...
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3answers
326 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 ...
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2answers
352 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 ...
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76 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 ...
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1answer
121 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 ...
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1answer
58 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 ...
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1answer
175 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 ...
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4answers
1k 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 ...
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390 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 ...
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1answer
176 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 ...
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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 ...
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2answers
330 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 ...
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2answers
197 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 ...
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1answer
65 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 (...
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2answers
552 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: ...
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2answers
507 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, ...