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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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Automobile 12V UPS circuit with Li ion battery

Currently I have a battery backup circuit for a GPS device to run on automobile power source and I am trying to improve a few things. Any help is appreciated. Currently I am facing issues of negative ...
user387542's user avatar
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1 answer
30 views

Checking battery capacity of 7 amp 12 volt AGM batteries for UPS

I have several 1000 watt Triplite sinewave UPS. The batteries had a date code of 2021 and testing with an 800 watt resistive load ,two heat guns,I was getting around 3 minutes run time,specs state ...
Tom Schulze's user avatar
1 vote
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68 views

How does the "earthing" system works in a UPS

PLEASE SEE EDIT 1 I want to know how exactly the earthing system works in a UPS, an example with by the ECOFlow RIVER 2. From their webpage it seems so simple, you charge the battery, switch the AC, ...
JoeyB's user avatar
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49 views

Fan noise due to Harmonics while running on UPS?

When mains is not available, ceiling fan will run on UPS and create a different sound/noise. I know that it is due to harmonics. But how can we remove this noise? By getting a high quality inverter, ...
DSP_CS's user avatar
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1 vote
0 answers
47 views

Shut down raspberry when unplugged from power thanks to a battery

Context and objective I need to properly shut down a Raspberry Pi Zero 2 W when it is (physically) unplugged from the power and power it on again automatically when it is plugged back. The basic idea ...
user3161330's user avatar
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1 answer
157 views

What is the purpose of the 4 diodes in this circuit?

I'm working on a mini UPS for my router (12V, 1A) and modem (5V, 2.5A). I've been checking out lots of DIY UPS tutorials and stumbled upon this one. It seems to do everything I need: it's got a ...
M-125's user avatar
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1 answer
76 views

Ceiling fan to run on UPS ONLY [closed]

I have my room typically connected on a UPS. During a power failure, the devices on the lighting line (5 A) are powered by the UPS. I have an air conditioner installed in my room which is on the ...
Anoop Pereira's user avatar
1 vote
0 answers
92 views

Get power for driver circuitry in an inverter

Planning to build an inverter based on egs002, I got high voltage high frequency side (ferrite core transformer including N-MOS and high speed rectifier) from old UPS board which I will drive using ...
asim's user avatar
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0 answers
57 views

Repurpose APC UPS with Solar Panel as DC-AC Inverter, what changes needed

Firstly I have these items lying around, 330W 24V Solar Panel, APC Back-UPS Pro 1000VA/600W with dead battery Wanted to see if I can repurpose this UPS circuitry to utilize solar panel during day time ...
ezio16's user avatar
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3 votes
1 answer
87 views

Can I add batteries in parallel to my UPS to get longer run time on battery [closed]

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 ...
Stephen Daddona's user avatar
0 votes
3 answers
98 views

Does DC-DC 24V-12V waste less power than AC-DC 220V-12V?

I am modifying an existing UPS to allow for a longer backup time. I plan on adding a cooling fan along with an external current controlled power supply to charge the larger batteries. There are some ...
Hanzala19's user avatar
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1 answer
57 views

Is back flow from UPS inverter normal?

I have a pure sine wave UPS / inverter for the combi boiler, and noticed a weird thing. That kind of UPS that has a big heavy transformer inside that is connected to a big car / truck battery. If I ...
Gogu's user avatar
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0 answers
42 views

Alternate power supply for dashcam, with latching relay

I am trying to setup dashcam with a dedicated battery for my car, I have a crude diagram to explain my logic. Yet to figure out detailed specs. The dashcam will run as usual car's ignition power, when ...
Alex Robbin's user avatar
1 vote
0 answers
101 views

How to design an inductor for the output of a low-pass filter for a 10 kVA sinusoidal UPS

The problem is that I have a 10 kVA sinusoidal UPS to repair and after replacing all the IGBTs and other components, I noticed that the low-pass filter output inductor is getting very hot at around ...
Renato's user avatar
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1 answer
73 views

Using two TP4056 modules to charge two cells in series

Here's an attempt to get use two modules of charges to charge and protect each of its own batteries connected in series. Adding back-to-back P-mosfets and a shottky diode converts the whole system ...
Benzine 's user avatar
-2 votes
1 answer
118 views

UPS cord has back-flowing current in it. What to do? [closed]

If the UPS is switched on and it's unplugged from the wall socket, then there's some current in the plug pins as per my neon line tester. It's a three pin plug. The earth pin has no current but both ...
Ojasvi Srivastava's user avatar
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64 views

How to calculate or estimate power inverter's peak power

What should be fine to consider as peak power output of an inverter when a motor starts for example? given that: Capacity (Rated Power): 935VA / 12 V Solar UPS Overload:110% Solar UPS Short Circuit ...
USER249's user avatar
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1 vote
1 answer
194 views

Ender 3 with a battery powered backup

I wish to develop a battery powered power supply to provide uninterrupted power supply for long duration 3D prints in an environment where mains power is unreliable. A regular ups power supply would ...
Lampshades's user avatar
-1 votes
2 answers
67 views

Can a generator with rated ouput 2.5kW handle 2 PCs rated 600W and 500W connected to two UPS rated 3000VA/1500W and 2000VA/1200W [closed]

I'm having issues with different answers from ChatGPT and Bard. I'm not an expert so I would appreciate an expert opinion. I have a PC rated 600W connected to a UPS rated 2000VA/1200W with a power ...
Sky Tech's user avatar
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26 views

Input/output USB power flow control depending on battery powered or wired

This seems like a very basic problem but I cannot really find a solution or come up with one on my own. The setup is simple (also picture for clarity): A circuit that takes 5V input Put a UPS with ...
André's user avatar
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1 vote
2 answers
215 views

Does power factor fluctuation affect my UPS?

I have noticed that my UPS is showing a power factor of 0.7 during the day and 0.55 at night. I did some online research and found that this is caused by load imbalance, and a low power factor means ...
IT Researcher143's user avatar
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0 answers
103 views

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 ...
Newbie's user avatar
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1 answer
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Can’t read code on blown capacitor

I have a blown capacitor with damaged code (maybe 102?45)it’s from a charging circuit board from an 8zed-2000S-12v-UPS inverter/charger/UPS.240v-15amp charger the markings on the board are NTC1. I can’...
Ross Widger's user avatar
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2 answers
57 views

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 (...
BMWW's user avatar
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0 votes
2 answers
234 views

How does this half bridge inverter charger charge the battery?

I just can't understand how this inverter charger actually charges the battery. The charging circuit uses two SCRs on the mains side of the transformer. The same transformer is also used to step up ...
Abhishek's user avatar
0 votes
2 answers
2k views

Earth Leakage Breaker Trips .. Where is the problem?

I am trying to install a UPS in my home .. diagram of the circuit attached. UPS is in first floor. Both floors have separate main circuit breakers .. Ground floor has Earth leakage breaker while First ...
O Ishtiaq's user avatar
0 votes
2 answers
184 views

What is the alternative for a capacitive power supply? [closed]

I am trying to make a UPS, which will need to pass safety regulations. I need to detect: When the mains AC voltage is present When the mains AC voltage is under/over voltage I thought of using a ...
Hazardous Voltage's user avatar
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0 answers
78 views

Is this a functional and reliable Reverse polarity protection?

Guys, I am trying here to design a UPS controlling board, I designed this circuit and it was to some extent functional and it draws approximately 16mA - 20mA (I don't want to use the traditional one ...
Hazardous Voltage's user avatar
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0 answers
110 views

Adding communication to a dumb 12V in-line UPS

Edit: By "battery" I mean DC-DC UPS, I did this to avoid any confusion with an AC-AC UPS that would sit before the 12V adapter, but it seems to have caused more confusion. This DC-DC UPS is ...
Facundo's user avatar
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1 answer
194 views

Help identify components

This board is from a UPS. I was trying to remove the defective SA1 switch and accidentally broke one of the pins of the “J63” capacitor (its reference is C22 but it’s not showing). The board part ...
arisk4's user avatar
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1 vote
1 answer
337 views

DIY Double Conversion Power Conditioner

I'm trying to build an AC-DC-AC converter similar to how an online double conversion UPS works, but I have a few concerns as I have only basic electronics knowledge and no real qualifications. I live ...
tonyvas's user avatar
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0 votes
1 answer
95 views

Lead-acid battery seems to be gaining capacity through use; why is this?

I am testing an alternative battery cartridge for an APC 3000 VA UPS. It's an OEM cartridge, but with the OEM batteries removed and replaced with Duracell 12 V, 5 Ah SLA batteries by a third party. I ...
Edward's user avatar
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0 votes
1 answer
30 views

RTC UPS power cycle on low battery

My RTC UPS switches on and off the whole time when the battery is low. I think it could be with the voltage monitor circuit as with the led indicator on the ups it shows the ups's battery voltage is ...
Lancerio's user avatar
1 vote
2 answers
179 views

Is it possible to pair MPPT/PWM charger with a computer UPS? Would it prolong the UPS battery's lifespan?

I've an old UPS for my computer which draws 50 W on average and less than 150 W at full load. With the the built-in battery I only have about 10 minutes of backup time. I am thinking about getting a ...
Pyi Soe's user avatar
  • 111
0 votes
1 answer
149 views

How to implement battery back-up?

My goal is to build a circuit that uses a battery (B) as backup when the current from a 5 VDC power supply goes away. When we have power there then we supply current to the load (R) and charge the ...
Clone's user avatar
  • 285
2 votes
3 answers
917 views

Will a 12 V DC/DC converter be damaged if it gets an external voltage (like 13.6 V) on its output?

I'm using a DC/DC converter (has an incoming voltage of 8-40 V, and an output voltage of 12 V) to connect it to a UPS instead of a lead-acid battery and power up some devices from a large capacity 4S ...
Dmitriusan's user avatar
1 vote
3 answers
90 views

Using li-ion instead of lead-acid in UPS (72 V-DC)?

I've got a UPS that charges its batteries with 84 V 1.5 A (6S1P SLAs). I want to replace the batteries with li-ion 20S2P. I'll use an external charger to charge them in cases of prolonged power-...
user3529406's user avatar
0 votes
1 answer
133 views

Diagnosing a transformer

I am diagnosing a 22 year old UPS (APC 1400RM) problem, the big transformer (430-7140A) is getting very hot yet the UPS works and self test reports fine. I suspect something is going to fail soon and ...
TSG's user avatar
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0 votes
1 answer
97 views

Can I use a device of 100-240 V~, 50/60 Hz on a 720 W/1200 VA inverter? [closed]

I am using an inverter back-up power solution device with 720 W/1200 VA output capacity. I have connected a sound speaker with the below specs: Input voltage: 100-240 V~, 50/60 Hz Input current: 200 - ...
teebo's user avatar
  • 105
4 votes
2 answers
868 views

Can I power a router, some HDDs and a Raspberry Pi4 from the same power supply?

I want to build a kind of NAS. See the plan in the picture below. Is it ok to power all the devices from the same power supply? A friend of mine warned me that it might not work because of the so-...
Marus Gradinaru's user avatar
2 votes
2 answers
468 views

Can I keep a 12 V lead-acid battery plugged in continuously?

I want to use the battery as a backup to a security camera that requires 9 VDC input. Can I keep the charger (12 V, 1 A or 14 V, 1.7 A) continuously plugged in to the battery and supply 9 V to the ...
Noah Boat's user avatar
1 vote
4 answers
428 views

MOSFET delay while switching

I was making a UPS for my router. My battery voltage is 8 V and V1 is the output from the power adapter, which is also 8 V. When the power goes off, the MOSFET should switch to the battery output, ...
Nathan's user avatar
  • 96
0 votes
3 answers
873 views

How can I decrease the relay release time when the current on relay coil is reduced slowly?

I'm trying to make a backup power supply for a home WiFi router (12V, 0.5A) and observe that the relay release time for a QYT73 relay is around 1 second. That is enough for the router to reboot, which ...
rodikno's user avatar
0 votes
1 answer
53 views

UPS doesn't provide any power on battery - Battery broken? [closed]

I have a CyberPower CyberPower BR850ELCD-AU UPS. It is a couple of years old and when I tested it a few days ago, I noticed that on battery, i.e. unplugged from power it does not provide any power to ...
halloleo's user avatar
  • 115
0 votes
3 answers
264 views

Uninterruptible Power Supply work from battery duration

I am going to buy an UPS, and on website that sells is written that model contains battery with capacity 9 Ampere-hours, 12V DC output voltage and UPS resulting output voltage is 220 AC. On the page ...
Stdugnd4ikbd's user avatar
0 votes
2 answers
61 views

Online UPS: Saving Power with solar panels [closed]

We have a 300kW online UPS for a data center. An AC/DC converter converts mains to DC, which is used to charge 2 x 50 12V batteries (50 connected in series each) and at the same time feed the DC/AC ...
Ctx's user avatar
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5 votes
5 answers
661 views

Is hysteresis needed for this non-inverting comparator?

I’m trying to figure out if the following comparator circuit (TL331) would be reliable in the following application, or whether I would need to add anything, like hysteresis. To explain the ...
Turboduinoz's user avatar
5 votes
2 answers
125 views

Classifying levels of dust and dirt inside power electronics

I have a fleet (100+) of 100 kVA and above uninterruptible power supplies across the UK. They are designed to be super reliable. I work as the "reliability engineer" so local engineers ...
scc268's user avatar
  • 176
0 votes
2 answers
183 views

Is it possible to use a Li-ion power tool battery while on a charger? [closed]

My plan would be to use a 20 V (x2) power tool battery with a step-down converter to power a 12 V radio. I would also like to be able to power the radio from the wall through the battery charger, ...
Gaweringo's user avatar
0 votes
1 answer
139 views

UPS for battery with minimum quiescent current

I am powering a PIR sensor which has minimum 3.4V of VCC and 70µA supply current with parallel Li-ion batteries and I want to switch on a boost converter when battery voltage goes below 3.5V. But the ...
CaveScientist's user avatar

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