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Questions tagged [12v]

Questions relating systems powered by a 12 volt supply. This may include automotive systems and lead-acid batteries that are nominally 12 volts although be aware that under many conditions the actual voltage may be several volts higher.

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46 views

What is the cost of converting 12V (lead acid battery) to 220V and back again to power 12V appliances?

I have a small house measuring ~ 8m x 4.5m. It is in Indonesia and power outages are expected daily. Probably the daily power outage is on average less than half-an-hour, but sometimes the outage can ...
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3answers
87 views

Motorbike turn-signal blinker starts OFF, I want it start ON

I bought a cheap blinker that claims to be good for LED bulbs (so the frequency is independent of the load.) It is true, but it has a flaw: the lamps go ON only after about a half second from when I ...
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1answer
48 views

Using a Computer PSU for its 12V output for high wattage loads [closed]

I'm looking to install some LED light bars (primarily designed for use on off-road cars) as fixed outdoor lighting on my property. I see they have models that use up to 700+ watts of power (for crazy ...
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0answers
22 views

TPS55165Q1 does not work in boost mode

I need a power supply that delivers 12v with an input between 8v and 35v. That's the reason I bought a couple of TPS55165Q1 from Texas instruments. I've made 3 different PCBs with a similar circuit. ...
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2answers
89 views

Will a 4 Ah 12 V battery be fine for a 2 A 12 V diaphragm pump + a Raspberry Pi?

I've got a 4 Ah 12 V lead acid battery which currently runs a Raspberry PI. I'd like to connect a diaphragm pump to this battery as well. The pump has a max. rating of 2 A. Assuming a fully charged ...
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1answer
62 views

Solar charge set up damaging battery?

I've installed a 12V 80W solar panel plus controller and attached it to a 12V 105Ah leisure battery. At first it (appeared to?) work. The charge status on the solar charge controller was at max and it ...
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2answers
120 views

What is the lowest voltage a 12V lead-acid battery in a car could be?

I'm trying to design a product that is powered from the 12V rail inside the car. In normal driving (engine running, electronics on etc.), what would be the minimum voltage of a low battery? Reading ...
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2answers
58 views

How can I get this 12v motor to run smoothly, and is it set up safely?

This is my first attempt at electrical engineering, so I'm sorry if this question seems basic, I couldn't seem to find answers anywhere. I want to wire a 12v motor to an on/off switch and power with ...
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1answer
86 views

12v DC brushless PWM fan burnt out via Arduino Uno

I’m working on a project where I want to control the speed of a fan using a microprocessor. I read several posts about using an Arduino Uno to control the PWM function on a 4 pin fan you find in PCs, ...
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2answers
59 views

Limiting current to a LiPo battery [closed]

(Updated: Amended text. The smaller battery is a lower voltage than I originally thought.) I have a small 7.5V LiPo battery that needs a top-up charge of max (say) 500mA from a large 12V LiPo battery....
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6answers
136 views

AND gate - 4 inputs, 12V

I want to make multiple AND gate input device. I have 4 locks (3 wires each; common, lock and unlock state) I want to monitor those states from locks and connect them to inputs (IC inputs) so when I ...
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0answers
70 views

How can I achieve 5V DC from 230V AC wirelessly? [duplicate]

I want to step down 230VAC so that I can have a large amount of current that I can transmit wirelessly through the transmitter coil to the receiver coil. I want to transmit it across 5millimetres ...
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0answers
116 views

How can i transfer 12 V, 50 Hz, 1 A wirelessly? [closed]

I want to transfer electical power wirelessly from a transmitter to a receiver coil. Input energy is provided by a single phase step-down transformer - 230V/12V AC, 50 Hz, 1,000 mA. Using the 12 V ...
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2answers
79 views

Best practices on splitting 12 V 20 amp supply into 5 devices?

I am running a 48 V to 12 V converter rated for up to 60 A on my custom pedicab setup. I'm fairly new at all things electrical and want to get this right. I have five different devices that hopefully ...
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1answer
78 views

12 V pulses with 100 MHz repetition rate

I have to control an high impedance load (> 25 MΩ) with 12 V pulses with maximum 5 ns of width and a repetition rate of 100 MHz. I can generate the pulses with the required shape using an FPGA ...
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1answer
37 views

Powering same LED strip from 2 drivers - diode?

So I'm looking at adding some LED mood lighting to our bedroom. End game is to have a single LED strip controlled by 2 different switches Currently, I have 2 switched 240V AC outlets, one either side ...
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0answers
42 views

12v power supply not putting out right voltage

Built a 12v power supply for music project. The "music from outer space" bipolar design, and my modules connected aint been working right. Tested the power output with multimeter and got 10v with a 1 ...
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1answer
51 views

Make ground signal last longer?

I'm trying to figure out a way to make a ground signal last longer on my car. I'll explain what is happening and what needs to be done. I'm hooking up an factory alarm on my car. It uses a negative ...
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0answers
36 views

Bypassing 110v power-supply on LED light-strip?

I am wanting to use 2 16.4ft rolls of multicolor LED strips in my enclosed trailer for lighting. They come with 110v power supply that plugs into another coverter that the LED lights plug into. Is ...
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0answers
29 views

Switching between two connections - adding LEDs to car reversing light circuit

I am doing a DIY project on my car and need some help. I have 2 LED COB on the back of the car, which is to be used for 2 different things: If I put the car into reverse gear, then the LED comes on ...
0
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1answer
45 views

How to measure available amps? Do i need more load?

My new 200W 18v 11a(max) solar panel reads about 24v 4a 50% efficiency at midday on my MTTP Rich solar controller. I presume this is not great. I was wondering... I have a 48v to 12v stepdown ...
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1answer
43 views

Increase voltage drop required to saturate PNP BJT to avoid noise

I have this circuit which must signal +3.3V or 0V depending on the switch status. The the switch is about 20 meters away and is getting EMI from mains. I realized that it only takes -0.7V of ...
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0answers
28 views

How to control single 12V LED with 3,3v GPIO? [duplicate]

Heyo! I need to control single 12V LED using Raspberry's GPIO To be more exact, I need to connect 12V LED & push button to 3.3v GPIO in order to control LED (on/off) and read button push events. ...
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1answer
25 views

Directly Using a Smart Charger with An Old Vector Hunting Spotlight? [closed]

I have an old hunting spotlight (http://documents.dewalt.com/documents/English/Instruction%20Manual/Vector/VEC184POB.pdf) which has a small 12V sealed lead-acid battery. The chargers that come with ...
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1answer
76 views

built in charge controllers take amps they need?

Many devices have built in charge controllers that stop charging when battery is at 100%. I read several places that you can charge devices with the manufacturers recommended voltage and that higher ...
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2answers
55 views

Van with Solar power but no auxillary battery and only on sunny days. Do I need switches and isolators?

I have a 2018 Ram Promaster city cargo van with OEM 12v 70AH 120RC Sealed Led acid battery and a 160a alternator. Sitting on top of the battery I have a 1200 Watt pure sine 110v inverter connected ...
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2answers
43 views

Connecting two wires to a DC 12v port on a controller board with 4 pads for a monitor

Sorry, the question was difficult to word. Basically I recently bought a controller board for a monitor and the DC cable I got wasn't correct. So until I get the right part, I just want to test the ...
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0answers
60 views

Charge a 12V marine/boat battery with AC

need to build a diode bridge to recharge a battery (car/boat type) from a boat engine that gives 12V AC. I thought of doing something like this: simulate this circuit – Schematic created using ...
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3answers
70 views

How is the fuse amp rating determined for a 12V AGM battery bank?

I would like to put 3 x 130Ah AGM batteries in parallel and attach a fuse to the positive terminal of each battery. What size fuse should I use? How is the amp rating of the fuse determined? The ...
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2answers
59 views

Is it appropriate to use the TB6621 or DRV8871 motor driver for powering 12V 1 amp motors?

I'm looking to make an Arduino powered rock crawler with 4 motors (want independent control of each wheel, also need to reverse). I'm looking into buying 12V DC motors that seem to have about a 1A ...
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1answer
160 views

Powering a radiator fan with 12V DC power supply

I want to run an old VW Fox's radiator fan on a 12V DC power supply. I have managed to burn out two of the PSUs so far. They work for a while but after a while they start overheating and die. I am ...
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2answers
96 views

Measuring the resistance of USB car chargers

I have a few USB chargers that are powered through a 12 V car receptacle. I measured their resistance with a multimeter, applying the probes to the contacts of the 12 V input. One of the chargers had ...
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0answers
40 views

Do I need a cut off circuit for my battery

Do I really need an auto cut off circuit for my battery when my charger only outputs 13V and 1A at max. The battery I want to charge is a 12V 7Ah Sealed Lead Acid. I heard that the cut off for lead ...
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2answers
49 views

Isolated DC/DC converter application circuit / usage

I'm trying to find a basic application circuit schematic for an isolated DC/DC converter – this one specifically: DCWN03E-12 – but I'm having no luck so far. The thing that led me to this particular ...
2
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3answers
68 views

would like to verify a filter design I need to make for a backup camera in my truck

I am installing a backup camera in my truck. I am getting some source of electrical "noise" in the electrical system in my truck and its not allowing the backup camera to operate. Let me explain a ...
2
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1answer
114 views

UL 840 clearances

The table 8.1 in UL840 doesn't consider clearances for voltages less than 50V (for example). I have to use a clearance of 0.2 mm on the PCB for the case of overvoltage category 1 and pollution degree ...
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1answer
32 views

Mini 360 DC Buck Converter [closed]

I have bought several DC Buck converters for my home-made 3D printer. I'm running a 24V PSU, but my fans are Noctua (12V) ones. So i want to convert 24V down to 12V. And the Voltage output works fine. ...
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1answer
98 views

Regulating 12v source to 12v

I wish to use a 12v deep cycle battery (I used to use this for my CPAP, when camping) put it on a constant charge, preferably a cheap trickle/float charge circuit, like found at Harbor Freight. I ...
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1answer
58 views

Particle Argon controlling 12V, using 3.7V LiPo

I am trying to control a 12V DC motor using a Particle Argon, powered by a 3.7V LiPo. To get 12V I am using this step up regulator, and to control the motor I am using this DC motor controller. I am ...
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0answers
38 views

Variable voltage relay (Open 10v and below, Closed 12v and above)

I need to trigger (close) a relay when my circuit voltage goes from 9v to 12v. Trying to keep this simple but fear that the voltage difference is too small for relay to open when voltage drops to 9v. ...
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0answers
40 views

Raspberry Pi + L293D to switch 12V solenoid valves

I am porting an Arduino project to Raspberry Pi. On the Arduino I switched two 12V solenoid Valves with the help of a L293D IC. It worked perfectly. Now I am porting this system to a Raspberry Pi. ...
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1answer
66 views

LED Lightbar as a turn signal [closed]

I changed my turn signals to LED light bars the other day. They are completely legal, but the issue I'm having is I can't use my parking lights and turn signals. The bulb that I took out and replaced ...
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3answers
1k views

Discharge time of 12 V 8.4 Ah at 5 mA

I have a motorcycle battery rated as 8.4 Ah (20 HR). It also says 8 Ah (10 HR) and I am not sure what the difference is. Anyway, I have a GPS tracker fitted with a rated ...
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1answer
54 views

Polarity. What do “C” & “P” signify?

G4 bi pin LED bulb. Silicone coated Hello all. Thanks for the forum. I have some of these: G4 bi pin LED bulbs. Silicone coated dimmable 12 volt DC. They are 1.5watt. Although not visible on this ...
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1answer
47 views

How to control a lightbar with 20 individual modules? [closed]

The TL;DR version of my question is, how do you control 20 pieces of 12V/1A outputs in the most reliable, compact and cost efficient way, with something programmable? The long version: I got a ...
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1answer
322 views

12v relay latching until no power [duplicate]

So I'm awaiting to wire in one or two relays so that a circuit is not powered until a push button is pressed. Then the circuit remains powered until total power is turned off. I've been trying to ...
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0answers
80 views

Boat wiring mystery puzzle

First post, please forgive any errors. Our dear father passed away leaving us his boat. The owner before had made some changes to the wiring (not for the better) leaving a tangle of loose ends and ...
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1answer
129 views

12 V 3.8 A water pump to 12 V 625CCA battery

Wanting to use car battery to power pump. Pump says it's 12 V 3.8 A, uses a 8 A fuse. Trying to sort out possible solar input needed to run pump but the numbers don't make sense. What size solar panel ...
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1answer
18 views

Dimming LED with speed controller

I'm trying to controll 4 parallel 12V DC LED strips with an speedcontroller. I am able to dim the lights from 100% lit to about 5% lit, but it never turns them off completely. My multimeter can't ...
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8answers
2k views

Using a 12 V 3 A bilge pump on a 12 V 8.5 A LED power supply

I recently bought the following for a grey water system project I'm working on: 3 x 12 V, 3 A bilge pumps 1 x 12 V 12.5 A power supply I'm not an electronics expert, so my assumption was that the ...