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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62 views

Raspberry Pi UPS circuit review request + improvements

Based on this question I created the following circuit: Since I made some (component) changes, first I would like to have a validation of the circuit for long-term usage (and some improvements). ...
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34 views

How to calculate: watts for AVR, VA (volt-ampere) for UPS

I intend to buy an AVR or UPS, and I want to add a few external HDD's & a few Mini PC's. I need to calculate how much power is used by every device so I don't overload the AVR or UPS EXAMPLE: ...
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2KW - 48V - 240v / 50Hz UPS - Unknown Topology

I am refurbishing a 2kw ups that a friend gave to me. It had failed and had been left in a shipping container on a site and the PCB had suffered some low level corrosion. The PCB is a 2 layer board, ...
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54 views

Uninterruptible Power Supply - Reset the load when power is restored

My system is powered by a redundant supply (UPS). When the input power supply is removed, the system detects this event and it performs a safe shutdown (actually it is a microcontroller that enters a ...
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30 views

Plastic Plugs in Surge Protectors or UPS

Would plugging 4 out of 7 outlets in a surge protector or UPS with plastic “safety plugs” to keep out dust/dirt harm the product in any way? I know that plastic is an insulator and it might affect ...
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61 views

UPS on DC lines

How could a UPS switch between battery and AC wall socket fast from around 4 ms to 12 ms. What make it especial to switch in that very low time. As far as I know it has relays inside it to perform the ...
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Why does the UPS mode of an inverter have faster switching times?

Of all the sinewave inverters I have used, they contain a switch at the back labelled Normal and UPS. When you put the inverter in normal mode, there is some 40-50 ms switchover time, enough to make ...
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54 views

Arduino for detecting low voltage on UPS

Scraping together some parts, I managed to build a 22AH 12V battery pack, but I don't want to damage the batteries. I am using 4x 12V 5.5AH UPS batteries wired in parallel. I have an Arduino Uno, ...
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53 views

UPS for ESP32 Microcontroller [duplicate]

I have two e-bike batteries. One of which i am using to power my ESP32. Now i want to switch to other battery when my batt-1 is low. I am switching battery using relay. But doing so, I suspecting i ...
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46 views

3 phase to single phase UPS 10 kva [closed]

I have a 3 phase to single phase ups 10kva. The Input voltage required is 332v to 444v/ 3 phase voltage with an output of 220-240v single phase. I have an external battery bank of 2v x 12 connected in ...
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140 views

Why shouldn't two AC sources be connected in parallel?

In data centers, servers usually have redundant power supplies, which makes it possible to plug them to two different UPS units. This way, the server continues to function correctly if one of the PSU ...
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53 views

Connecting a multi-PSU server on different lines with different earthing

I am currently preparing to set up a new server which has two PSUs (for supply redundancy). Of course it would be logical to connect them to different sources, but the situation I'm dealing with ...
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4answers
72 views

How to know how much energy storage has powerbank? [closed]

I just looked to this question and I don't understand how to know how much Wh this powerbank has (click "Specifications" tab), because it has different output voltages and I don't know how to ...
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114 views

DIY UPS for Home Automation/Energy Management system

OK, the original post asked too many questions and I was asked to rewrite the post question. So after reviewing the old post and rethinking the project here it is. So, as requested, I will ask 1 ...
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1answer
56 views

Use an Powerbooster 1000c as an ups for an RPi

I'm a pre-newbie hoping to some day reach newbie status. These questions are probably stupid but I would appreciate your input. EDITEDITEDITEDITEDITEDITEDITEDITEDITEDITEDITEDITEDITEDIT I'll try to ...
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33 views

UPS For Mac Mini-based laptop - Sanity Check

My project is home-brewing a laptop that uses a Mac Mini and a small ~7" LCD display. To make it truly portable, I'd like the power system to work like a commercial laptop - ie, powers and charges off ...
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53 views

Switch between 2 AC sources for a DIY Arduino-based UPS

I want to build a UPS that when the main AC source is under-voltage or not available, it will automatically switch to the inverter's AC output and when the main AC source is available again, it will ...
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Bottom solder on the UPS PCB [duplicate]

Today i was looking at PCB of an old ups system. I noticed that there is a bottom solder pattern on the back side of the PCB, right under the IGBTs I believe that soldering the high power line on the ...
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28 views

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 ...
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1answer
137 views

Poor Man's UPS for a Microcontroller

I'm planning to create a Control Box for my Home Solar System which will involve using a microcontroller (STM32F103C8T6) as my control system. This uC will handle my current sensing for power ...
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1answer
67 views

Can I use an h-bridge as a changeover circuit?

I have solar controller which outputs battery voltage when available. I also have a switching psu as backup. What I would like to do: Use an h-bridge, connecting its battery negative terminal to my ...
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1answer
119 views

Does return path need a diode?

The following circuit contains an Uninteruptable Backup System (UPS). So if the main battery fails, the UPS auto-switches on to power the essential instruments. (The UPS senses the voltage drop.) ...
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2answers
118 views

Unexplained amperage spikes

IT guy here - I have a device called a WattBox in one of my networks so I can remotely cycle power on an outlet. It also provides me with alerts when something falls outside set parameters. I've ...
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44 views

What can I do on the bench to determine if a power supply does or does not add back a PFC (Power Factor Correction)?

I'm given a AC to DC power supply with only the inputs and output specified. It was probably made after 2000, and the ENERGY STAR program mandate to add PFC correction to power supplies may or may ...
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110 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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73 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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94 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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32 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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29 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
813 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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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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92 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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220 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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43 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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67 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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115 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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53 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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60 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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130 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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114 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
132 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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2answers
124 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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147 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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227 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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128 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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158 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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76 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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107 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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81 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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340 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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