Questions tagged [backup]
For questions about backup circuits, such as a battery backup.
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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 ...
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Design for passive power backup for ESP32 for a few milliseconds
I am designing a logger system with an ESP32 in which the logs are uploaded to the IoT cloud and parallelly logged to a local SD card. On Power loss detection, I want the ESP32 dump all the data that ...
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VFD runs has backup generator, breaks down twice
I am Electroman, but very ignorant in electrical knowledge. I have a problem.
We have an irrigation pump connected to a VFD that runs on the electrical grid but is connected to an emergency backup ...
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2
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Backup power supply for car stereo
I built a home stereo for my son using a car stereo and computer power supply. Unfortunately, I lose memory from the head unit every time the power is switched off. From what I understand, I need a ...
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How isolate IO pins of Arduino and PSU output?
I will start by saying that I am a beginner of electronics and I don't have much experience hence I am making this post asking for advice from more experienced peopled than me.
Now that I have lowered ...
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Connecting multiple DC Sources (DC Bus)
I have a large area which I want to cover with camera and other low power devices. These devices are outdoors, and quite far away from where my intended main power source will be (say 400m). I'm ...
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Looking for a circuit to run a 12 V toilet exhaust fan when utility power fails
I have a tiny house.
Recently my inverter failed and it could take weeks or months to have it fixed. It's a 48 V DC solar to 240 V AC, that is intermittently working with a non-working 5 kWh battery.
...
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Can I use a power bank to power my laptop during a blackout? [closed]
I am wondering if it's possible to use my ThinkPad L430 laptop with a power bank as a power source during a blackout. The laptop's power consumption is between ~35 to ~42 watts. Its battery is always ...
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5 V holdup/ temporary backup circuit
I have a project where I'm using an android tablet to power a serial relay, the relay is 20 m from the tablet so I'm using a USB C > USB A hub and a self powered USB over CAT6 extender. When the ...
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Short term power supply
As a cheaper or longer lasting alternative to a battery, what else could maintain electricity for a second or two or more for a computer, PS4, TV or other similar devices when the lights are ...
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How does this power supply design work?
While looking at a radio unit I was trying to repair, I found a 5V line at 1.2V. I started to reverse-engineer it, but was later able to obtain the schematic:
The right side is the input, and ...
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Can I connect a separate charger and inverter to use a LiFePO4 battery as a backup for a household pump?
I have the following equipment and want to know what I need to make this a functional battery backup for a sump pump.
12 V, 100 Ah Smart LiFePO4 battery
Victron BlueSmart IP65 Charger 12 VDC, 15 A
I ...
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3
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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 ...
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12 VDC to 380 VAC for 1 kW, 3-phase motor
What is the cheapest way to run a 1 kW, 3-phase motor for about 20 minutes on a 12 VDC battery?
Will it be a 2 kW inverter to power a VFD or is there something else?
And will a 100 Ah battery do, and ...
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48 V phantom power backup: switch off the 9 V backup battery with FET
I found this device here on the site.
I need something to switch to a 9 V backup battery when there is a 48 V phantom power outage.
How can I change the FET to switch OFF the BAT1 (9 V) backup battery ...
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How to throttle / load balance between utility and battery power supply
Basic queation - What kind of circuit allows me to throttle the power draw from two different supplies? i.e. 80/20 from a battery bank and utility power, respectively? Or 60/40, or 100/0?
Main idea - ...
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Leaving super-capacitor connected to power supply
I want to use a 1F-5.5V super-capacitor as a power backup for a 3.3V circuit. As I searched the internet I have to use a circuit for charging the super-capacitor to stop charging when the voltage ...
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Can I use mains as backup for off-grid solar system?
I want to run 6 freezers/fridges (10kWh/day) with a 4kW array of solar panels, 4x 300Ah 12v LiFePO4 batteries, and a 2kW 12V Projecta Intelli-Wave Pure Sine Inverter.
Instead of using a generator as ...
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Can a memory backup supercap hold on for more than 2 weeks?
Most RTC chips have a VBATT input for backup power supply; besides a battery, you can use a supercap there, e.g. using the following scheme:
simulate this circuit – Schematic created using ...
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Frequency reading 180 Hz on only one line to line measurement in three-phase backup 60 Hz LP gas powered generator in idle mode
I am running into an issue I don't understand why is happening. I have found how to "fix" it, but I am interested in ideas on what the actual source of the issue is
Short version:
I have a ...
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2
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Automatic battery backup from mains to battery bank on power outage
I've looked for solutions and cannot find anything that's clear to me that accomplishes what we need.
Components:
12V furnace 8A load (fan)
120V to 12V adjustable power supply
12V backup battery bank
...
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SAM4N Backup Mode - no wakeup
I do have an ATSAM4N and try to go to backup mode as soon as the external power is turned off to keep the RTC time running. Therefore, a battery is added to support VDDIO.
I manage to get the SAM4N in ...
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12V battery back-up system using a relay
simulate this circuit – Schematic created using CircuitLab
I am trying to use a 12V battery as a back up power source. I made this circuit but it doesn't work properly.
When the adapter is off ...
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Adding 12V DC jacks to desktop UPS in order to connect ONU and router
I get a backup of only about 10 minutes when my FTTH ONU and WiFi router are connected on the 220V ports of my desktop UPS. So, in order to avoid the conversion loss, I want to install two 12V DC ...
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What parameters to look for in selecting D2 and Q1 for 3500 mA backup power?
Which transistor and diode is suitable for fast switching power and low discharge battery when Vin, for PWM 1.2-29 KHz, 4 A, 3.7-5 V?
And which capacitor should be at the output to smooth the ...
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Can an ideal diode pair (evaluation board) be used for backing up one battery with another?
I'm trying to use 2 ideal diodes [within a MAX40203 evaluation kit] for "OR-ing" two battery power sources... to extend the length of time for driving an outdoor flag light. My understanding ...
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Selecting components for high current backup switch
Does anyone have any pointers or tips on how I can select the correct PNP transistors and resistors for the following circuit?
If I need to drive up to 1.5A do I need MOSFETS instead of transistors?
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Can I use direct 12V batteries to power PCs/cameras/Raspberries instead of converting to AC and then back to DC?
I'm planning on building a new house. One of the things I want to do is to set a special powerline for all high priority electronics like cameras, PCs, Raspberries (for domotic system.)
My idea is to ...
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super capacitor's maximum charge current
I am designing a backup system based on a supercap and an LTC4041.
The calculations by the guidlines in the datasheet brought me to the folowing parameters:
Capacity:2.4F
Charge current: 1A
charge ...
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499
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Super capacitor backup circuit
I want to implement a momentary power backup in my circuit using a supercapacitor. I have come up with the following circuit. Am I right in implementing the super capacitor like this? Also, the input ...
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5V battery backup supply for GPS
I designed a circuit to do the switching from a 12V car battery to a 8.4V Li-Po battery with a relay. Both batteries go through an LM7805 regulator to supply a constant 5V to a Raspberry Pi.
When I ...
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Capacitor as power buffer for battery change
I have a quite simple question and quite a simple circuit in mind.
I have an application, which is battery powered and uses a RTC clock for timekeeping.
I would like to preserve the time during ...
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What could be causing my APCs to buzz from time to time, and for my Tesla to stop charging? [closed]
I have two issues happening at the same time (very much related).
The APC brand UPS backups in my office all start buzzing at the same time, then click once every 5-10 minutes. This happens at all ...
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Power source switching/isolation circuit
I'm currently designing device which will be powered from external PSU but also will have backup power system from battery. I'm trying to solve my problem.
When external power source is down (5V - USB)...
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2 x 90 Ah 12v deep cycle batteries in series runs 77-90w for under 20 minutes. Why?
I am trying to understand the maths here. I have 2x90Ah 12v batteries in series (24v) and they are powering my computer. The peak power is 120w while the computer is shutting down during a power loss. ...
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Altium Designer Deleted schematics completely
I opened up Altium after a windows update, and received this error:
...
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230V mains back up with 12V battery and inverter
I am looking to have a 12V battery back up if 230V is lost, to supply a mobile router for security cameras (solar charged battery powered) outside a house when vacant.
I have a 130Ah battery in a ...
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Connecting Charger + Inverter to deep cycle battery
It's a really simple question I believe, but I just want to make double sure it's okay. Can one simply clamp a mains charger as well as an inverter onto a deep cycle battery, or does one need any ...
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Battery Charging Backup Circuit
I am relatively new to electronics and circuits. I'm modifying an alarm clock to have a battery backup. I've found a few circuits that show how to build a battery backup circuit and it makes a lot of ...
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Do home UPS (mostly advertised as inverters) have a rectifier built in?
This is regarding home UPS/inverters which are typically known to convert the DC from the battery to AC, so the AC can be used for household purposes.
What I don't understand is how the batteries are ...
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Replacing Dallas NVRAM with larger capacity variant?
This DS1225AB-200 (8k x 8 = 64kB NVSRAM) is from 1995 and is probably dead (cannot measure from the outside.) The only close replacement in stock is a DS1230AB-100 (32k x 8 = 256kB.)
Looking at the ...
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Using two diodes as a simple power supply backup switch
I saw this module as a "battery emergency switch module" for $2 on aliexpress:
which is just a relay energized by the external power supply, and when the external supply is gone, connects ...
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Will this DC UPS with off the shelf components for home network and laptop work?
I am trying to build a DC UPS to power modem, router which have power requirements of 12V 2A and a laptop which has power requirement of a 20V 3.5A.
I am planning to use a AC to DC SMPS which is ...
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DC backup battery switching module
It is common to find these cheap Backup Battery Switching on the internet. But the issue I have with these ones is the load gets reset when switching from the main source to the battery. It seems like ...
user115094
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is it okay 4 years old used UPS Battery filling sulfuric Acid insted of Distilled water?
I've 1250VA UPS where I found 2 battery (12V-9AH). which Is used for 4 and years more.
When I brought this UPS it gave almost 80 to 90 minutes backup but now it only lasts for 15 min.
so I decided to ...
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Same mAh, same volt - different current
I need to replace the 18650 battery of one application. The battery doesn't have any marking about volts, mAh or amperes.
Because it's 18650, the voltage is fixed - done. mAh - will use 2000mAh (let'...
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Some basic questions about voltage and lithium power pack
Well, I've been stuck at home and since I've run out of things to do, I've started thinking about creating a simple cheap backup for my modem, router, and desktop fan.
Since I've got several lithium ...
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crystal oscillator as backup (or with sync)
I have a device that generates a 49.152MHz frequency, but depending on its status it can cut it off from time to time. This frequency synchronizes my MCU's audio devices, but it must never be stopped. ...
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Replace 173 Wh lead acid battery with 20000 mAh power bank
I have an APC BX1100C 173 Wh UPS that I use for my computer. I also have a 20000 mAh power bank with output voltage of 5 V.
What do I need to do to replace UPS battery with this power bank? Is this ...
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One battery backup, two garage doors
I have made a very simple battery backup for my garage door: 2 x 12 V batteries in series connected to the battery terminals of my opener.
This charges the battery and switches to backup on power ...
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