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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Building a UPS for Raspberry-Pi

I am trying to build a 5V/2A uninterrupted power supply (UPS) for my rPi B+ using LM7805 and some phone batteries (3.8V/0.5A and 3.7V/2A) or any of the 6 pcs 18650 batteries (3.7V/2A) that I have ...
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2answers
112 views

Extending the backup runtime of a UPS with an external car battery

I'm looking for a simple/inexpensive way to have a longer power backup time. My fist thought was putting 2 cheap UPSes in parallel. But I quickly found it's not that simple. You would need another ...
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1answer
91 views

Is it possible to connect a UPS in parallel with the mains?

Short version: When a UPS is plugged in to the mains, is it possible to plug the UPS output back to the same mains? Will that work as an emergency power backup for the mains circuit? Longer version: ...
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1answer
83 views

Fast Switching For UPS

Well I don't even know how to call this question, but the point is. I am making a DC UPS, and I want to be able to quickly switch from the wall supply to the battery supply, and I don't think a relay ...
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58 views

Inverter using battery even when mains power supply is on [closed]

All the points connected to the inverter are using battery power even when mains power supply is on. When inverter is turned off , those points connected with the inverter have no power, not even ...
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2answers
273 views

Relay not switching immediately from switching power supply to battery backup

WARNING This project as currently described is badly flawed in a number of ways that are liable to lead to complete failure of the equipment. As it is stated that it is intended to be used in a life ...
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1answer
70 views

How do we detect when Power Source from EB to DG

Is there a way we can detect if power source switch from EB to DG? Are there any circuits or alarms already there in market which triggers when the power source changes from Normal Power Supply to ...
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1answer
55 views

UPS makes sharp short-circuit sound when close to full depletion [closed]

I'm using a 1500VA Xpert UPS which supports my CPU (Cooler Master's GXII Pro 750W power supply) and Monitor (ViewSonic VA1703wb; 21W). The problem is that when the UPS is depleting (AC ...
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1answer
126 views

Low voltage DC Supercap UPS Design

Most generally I'm looking to design a UPS for a low power DC device given higher voltage AC current, with storage handled by a supercapacitor, or a bank wired in parallel. For my specific case I'm ...
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2answers
96 views

Measuring internal resistance of a battery while it's being charged

I was startled to hear that there are devices out there that can measure the internal resistance of batteries, in circuit, while the batteries are being (trickle-)charged. For example, Hioki markets ...
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1answer
77 views

What will happen if i connect a bulb across 2 AC sources of different voltage [closed]

I was just trying to decode whats happening in my house wiring I have a Fault line indicator bulb for each phase,Sorry i dont know How its connected or anything ... Recently i installed Home ups And ...
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3answers
187 views

Rate my Rasberry Pi UPS

I've made simple schematic for a UPS for Raspberry Pi. It contains a 12V Lead Acid Battery (40Ah), 5V LM7805 regulator and some capacitors. I'm supposing max 1.2A load from Raspi. Should I add ...
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1answer
108 views

12V UPS power supply and battery [closed]

I'd like to use a Tripp Lite PR40 as a backup 12V UPS by connecting it to a battery before a couple motors in parallel. The battery is 125AH deep cycle AGM. Can I do this? The manual says that the ...
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2answers
118 views

UPS battery replacement

For the UPS model Niky 900 by Daker, I'd like to replace the original CSB HR1234W F2 battery with something I can buy on amazon.it, e.g. FIAMM models: could you suggest what are the relevant ...
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1answer
112 views

Strange sound in speakers when the refridgerator goes standby [closed]

I live in a room which has two power sockets and the following devices, as illustrated in this diagram: https://docs.google.com/file/d/0Byu0T6y2SLeENDdvNGVCWHFBWmc/edit All devices look exactly as ...
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1answer
249 views

Protecting a wireless router from voltage fluctuation

Background: I have a wireless router ASUS DSL_N12U. Input voltage and current is 12V , 1.5A respectively. I also have an Inverter (works on three modes: Solar, Battery, Mains) at my home. Problem: ...
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2answers
178 views

UPS 12V power switching

I was trying to make a sort of UPS circuit with a 12V DC 5Ah power supply and a 12V 5Ah seal-lead battery. My question is that I don't know how to switch quickly from line supply to battery. I've ...
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92 views

UPS relay circuit

I have acquired about 500amp hours worth of UPS type deep cycle batteries. I am looking to build my own UPS/Charge circuits. (I hope) To charge: I plan on using a standard 110V mains powered battery ...
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0answers
88 views

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 ...
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2answers
263 views

UPS batteries and hot/cold weather

I am designing a small network deployment for several buildings without temperature regulation. In planning the power, I can find very little about acceptable UPS batteries for these conditions. ...
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2answers
198 views

Designing a low voltage UPS

Preface: I am designing a UPS such that if the AC main fail the device can continue to run for at least 10 days. My goal here is to make a design that can last years off a non-rechargeable battery. ...
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3answers
86 views

Emergency 3-phase power supply in the event of power failure

I have two Magnum 400 10/20 drivers running two stepper motors. Peak power consumption is about 2 kW. In the event of a power failure on the 3-phase supply, I'd like to trigger a controlled emergency ...
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2answers
128 views

Battery Size for a UPS

I have a 250 VA UPS, and I have a couple of devices I want to run on it, a radio (7 watts) and a fan (55 watts). How do I calculate the required battery size (ampere-hours) (for a 12 V car battery)? ...
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2answers
2k views

Converting Inverter Output from Square Wave to Sin Wave

I bought a UPS, it has output of 220v AC, the problem is the output is square-wave, which causes distortion on TV/LCD, is there circuit that can take this Square-Wave as input, and output Sin-Wave? ...
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1answer
126 views

Is this DSP sinewave inverter a marketing hype?

There are some companies in my country(India) which try to sell inverters for home marketing in the name of DSP Sinewave Inverter and claim are superior to normal sinewave inverters. I am trying to ...
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238 views

12v capacitor / UPS system [duplicate]

I am looking to make a capacitor/UPS system for a few different electrical components in my car. I want to power the rear view camera, headrest monitors, and possibly the head unit for about 30 ...
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1answer
63 views

Need to know battery configuration for a 250 watts inverter [closed]

I have a 12 Volt inverter which have ability to produce 250 W output. I would like to purchase a battery for this. can any one tell me the configuration of battery ? eg: Minimum AH
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1answer
2k views

50/60Hz inverter output inductor design

Given a SMPS PWM inverter (for example an UPS) supplying voltage/current at 50/60Hz, how do you design an output inductor? I don't mean how you compute its value in uH/mH nor its current rating in A. ...
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3answers
237 views

Diode rating for a UPS project with extra battery

I am planning to add an additional 12volt deep cycle battery to my APC UPS but I dont want to use the charging circuit built into the UPS. I think that if I throw in a Diode between the external ...
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1answer
691 views

Backup power for adsl modem

I want to create a circuitry for switching to backup power (small battery) in case of mains power failure for my ADSL modem (to avoid the internet going down in such scenario). This is a basic ...
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1answer
57 views

Can I use a UPS to compensate for unsteady line-power? [closed]

One of the outlets in my home provides unsteady power that causes connected electronics to occasionally shut down. If I buy a battery backup device such as this will it be able to compensate for ...
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1answer
365 views

Humming Sound of UPS vs DSP Inverter

I have a APC 1000VA BR Smart UPS.I have noted that the UPS Produces a Humming Sound when running on Battery Power.But my older a normal 500VA UPS(not from APC) seems to produce far lesser humming.The ...
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1answer
706 views

Will a PSU with Active PFC Work with Normal UPS

Im getting a Seasonic SII 620 with Active PFC.The problem is that i have a pseudo sine wave ups or just a normal UPS.Will this PSU work with the back up power offered by the UPS?
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2answers
212 views

Buffering AC supply voltage and detect power loss?

I'm designing a system integrating: an industrial PC with 230V AC input (~300W) various peripherals requiring 24V DC (150W max) In case of external AC power loss, the DC components (2) need to be ...
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2answers
120 views

Is it possible to charge 3 parallel batteries without sending charge to the UPS?

I have a UPS (uninterruptible power supply) with a 220VAC input designed to be used with 12V batteries. It has a rated capacity of 400 watts and I've placed three 12V car batteries in a parallel ...
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3answers
714 views

Convert 320VDC to 220VAC or 48VDC voltage using 220VAC (UK) UPS?

I've got access to 12 flexible Solar Panels - 320VDC each Main voltage is 220VAC (here in the UK) and also might buy an electric engine running at 48VDC. Would a 220VAC Uninterruptable Power Supply ...
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2answers
373 views

Trouble using marine batteries with UPS

First, let me premise this question with the fact that I'm not well versed in electricity. Here's the problem: I am trying to power a UPS with an inverter and two deep-cycle batteries run in ...
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3answers
367 views

Is there an instrument that can measure the capacity of lead acid batteries

Background I have an electrical scooter with 6 x 12Volt lead acid batteries (72 Volts total), which are now in such a condition that they can barely get me to my work and back. I got a bunch of used ...
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1answer
622 views

Will a trickle charge lead-acid battery system last?

If I were to implement a simple battery backup system like this to power several WiFi radios in a field situation, how would the battery handle it? Would trickle charging it like that wear it out ...
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1answer
69 views

Clarification regarding batteries and ups

I am planning to setup a ups with 2 100ah/4h batteries next to my server setup. Is it safe to work to work next to such high load batteries. Are there any health concerns that comes with working ...
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1answer
148 views

Why UPS for sensitive SMD development?

My friend suggests me UPS for SMD development. I already have a a surge protector over all devices. He recommended the UPS that transmit all energy through its battery and he recommend to find some ...
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2answers
2k views

What types of batteries are typically used in UPS (uninterruptible power supply) and why?

They definitely need to be safe for indoor use so they can't vent, they should probably support deep cycling due to the nature of backup power supplies, and I imagine they should have relatively long ...
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1answer
2k views

Troubleshooting UPS failure

My wife said her office had an old UPS that was being scraped because it wasn't working. I picked it up and plugged it in and nothing happened. No lights, no warnings, nothing. It's a small ...
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3answers
19k views

Battery Backup: C10 vs C20

I am installing a home UPS system of 1400 VA. The UPS is a 24 volt system and, based on the batteries available on the market for the UPS segment here, will need 2 x 12 volt batteries for it. Based ...
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1answer
155 views

Does a low-quality UPS affect its battery life?

People say that "local" UPSes (uninterruptable power supplies) reduce the life of their batteries while other, "branded" UPSes are better and do not affect the battery life. I have noticed that a ...
0
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1answer
447 views

ups 12v 9ah batteries not charging [closed]

I have a 2000VA ups that contains 2 batteries ( 12V 9Ah ). I think that something happened to the batteries, since now they can barely handle an average laptop for about 3 minutes before shutting down ...
7
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1answer
366 views

volt-ampere (VA) rating of UPS

I would like to ask about the volt-ampere (VA) rating of UPS. Is there any effect of this value in terms of the time period that the UPS can supply the power?
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1answer
181 views

Should I look for Aluminum or plastic enclosure for UPS

I am on the process of material selection for the UPS I am prototyping. My plan is to manufacture a product that should finally go to the market. I am relatively new to the manufacturing and I would ...
4
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1answer
315 views

Tapping the battery from an UPS to feed low voltage devices

My UPS powers one 120V AC device and a whole bunch of small 'bricks' that end up rectifying things down to 5-12V DC. Instead of using the 'bricks', my idea is to tap the battery directly, and use ...
4
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2answers
2k views

Replacing a battery in a UPS

I recently replaced the battery in my APC Back-UPS CS 650 and of course I didn't opt for an original APC battery, but just bought a similar one from the corner electronics shop. Apart from the ...