Questions tagged [batteries]

An electric battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy

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1answer
60 views

How to solder the 4-pin battery connector back to phone's motherboard?

One wickedly hot day the battery of my old Nexus 4 swelled up. I use that phone as Android development platform, so most of the time it was plugged into the computer for USB debugging. It's been ...
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0answers
45 views

Li battery charger reference voltage problem

schematic datasheet I have designed a battery charging circuit for a lithium ion battery.When i connect a battery the charging IC seems to do nothing. Only when i use a multimeter probe to measure ...
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2answers
37 views

Batteries connection for 3 wheel e-bike

Goodday. I need info on this. If i connect say 3 x 12 volt 28amp batteries in parallel to increase the amp hour that makes it a big 12 volt battery and then connect 2 x 24 volt but lower in amps ...
2
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0answers
37 views

24-60V Precharge schematic critique

I'm looking to design a soft-start precharge circuit for starting up circuits with substantial input capacitance (~1.5J @ 24V). The main requirements are: 24-60V compatible Constant current pre-...
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3answers
60 views

How to monitor the voltage of a bunch of batteries using Arduino?

Ive got about 36 batteries that all stay between 2.8v and 3.6v, and I want to be able to accurately monitor the voltage(and therefor the state of charge) of all of them using an Arduino Nano, the two ...
0
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2answers
29 views

Counting pulses in low power device

I have a mechanical water flowmeter with reed switch output and I connect it to my low power, battery powered device to count pulses. The reed switch is connected to my device via a 15 m long cable ...
0
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2answers
90 views

Raspberry Pi Zero 12V Battery backup to 5V - do I need the resistor?

I found this diagram on the internet which seems to divide the voltage down to 5V and still be able to deliver 1A with the 7805 just like I want. It will use a 12V lead acid battery and a 12V IN ...
0
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2answers
89 views

Lithium ion (Li-ion) vs. Lithium thionyl chloride (LTC) battery?

I need some consultation on which battery of the two to use for the GPS trackers I'm designing. My trackers wakeup when there's movement only so they're not on all the time and they have low power ...
0
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1answer
53 views

How can I limit the current drawn by a Li-Ion battery pack BMS?

I have a Li-Ion battery pack made with twelve 18650 in a 3S4P configuration, using an off the self Battery Management System (rated for 25A), that I purchased on aliexpress. I tried to charge it using ...
1
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1answer
51 views

Reading a low voltage signal from a battery connected to a transformer

So currently I am trying to read the current draw from a battery that is being run through a transformer to generate an arc to light a gas burner. I have a roughly 1 ohm piece of wire that I am ...
1
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0answers
42 views

Voltage step up module and if I am using it correctly

I am making a "simple" bluetooth speaker and have followed instructions from a Youtube video on how to assemble the components I have bought. However... I am finding that the rechargeable li-po ...
0
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0answers
35 views

Connecting a 12v router to a 12v battery [duplicate]

can I connect a 12v router directly to a 12v battery which normally will be at 13-14v (because most of the time it’ll be charging)? The router is a TP LINK Archer MR200 rated at 12V 1A
1
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1answer
75 views

Can anyone help me identify this component from an old rechargeable battery pack? [closed]

I was given an old, maybe 10 years, battery drill, it had seen almost no use, but, unsurprisingly, the battery pack would not charge. I took the pack apart and several of the cells were obviously ...
0
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3answers
101 views

How to block reverse current from battery to charger (DC-buck CC/CV module)?

The set-up For a project, I have a set-up where the power to the main load comes from either a AC-DC adapter input (24V) or a battery pack (12V to 16.8V - 4S4P 18650 Li-ion cells). The battery pack ...
1
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0answers
31 views

Changing between usb power and battery power using P-Channel MOSFETs and a CMOS Invertor

I am trying to switch between USB power and a single cell lipo using two mosfets. Would the circuit below be ideal or is there a more efficient/reliable way to do this? When the USB is connected the ...
0
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1answer
25 views

BMS for 2S Lipos

I have 2 lipo batteries in series, each has a built in protection circuit and these specifications: Voltage: 3.7 Vcc Capacity: 1000 mAh Maximum discharge rate: 2100 mA I need to charge them, but I ...
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0answers
35 views

12V Lithium Ion Polymer Battery

I am trying to develop a product that requires a 12 V portable rechargeable battery that can output at least 2 A. Since conventional LiPo battery runs only on 3.7 nominal voltage, is it advisable to ...
-1
votes
2answers
54 views

Unknown Battery Connector [closed]

Hi, this is a standard 260mAh 3.7V battery. I've seen this on several listings on eBay, Aliexpress however nobody says what this connector is. In particular I'm looking for the receptacle part of ...
1
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1answer
50 views

Bypassing battery cell with transistors

Is it possible to create the schematic below with transistors in any way? As I see it, there is no voltage difference between j1 & j2, so a transistor connected the normal way would not work. ...
2
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4answers
155 views

How would you wire small computer to run on both batteries and AC power? [closed]

I'm trying to use a motherboard (Mac mini 2018 model) for a project that will require it to be able to run off batteries. The project is essentially building a custom laptop using the Mac mini mobo ...
0
votes
1answer
28 views

Power switch: leaving battery connected at one terminal

Just wondering if there is any real-world practical difference between a power switch that disconnects both terminals of a battery vs a switch that just disconnects one terminal. Are there any ...
1
vote
1answer
18 views

MAX856 Low-Battery Indicator Question

the MAX856 says it has a low-battery indicaitor. My setup has a single 3.7v nominal LiPo pouch and I want it to trigger the low-battery at 3.4V. Datasheet: https://datasheets.maximintegrated.com/en/...
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0answers
62 views

Reducing Current?

Having a problem with my EV a converted Fiat 500. The conversion is made with part from companies that dont exist any more, so it is hard to get information about them. The car have two batterybanks ...
0
votes
1answer
38 views

Custom charger with solar cell

I want to make kind of autonomous power supply for my RPi. So that I am planning to use 12V solar cell and batteries for this project. Also I will use Arduino to controll all of this stuff - to ...
2
votes
1answer
97 views

Accidentally used 3.6 volt battery for my mouse, now it only works with 3.6 volt [closed]

My mouse requires AA 1.5 volt batteries to work. I accidentally used a 3.6 volt Li-SOCl2 battery. Now it works fine with the 3.6 volt battery but doesn't work at all with a 1.5 volt AA battery. I ...
0
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0answers
42 views

Current and voltage increasing with duty cycle from buck- converter

I am designing a 2s Li-ion battery charger using a buck converter from a 10W (18V, 0.55A) solar panel. So I understand that the duty cycle controls the ratio of the input power vs output power and ...
1
vote
2answers
61 views

How to calculate remaining battery capacity from charge discharge data?

If a dataset contains data collected over time from a re-chargeable battery and includes information such as voltage, current, average discharge rate and peak discharge rates. how can the remaining ...
0
votes
1answer
95 views

Protected 18650 batteries shut down after I introduce a capacitor to the circuit, why?

I have a 24V audio amplifier that is powered by 8 packs of 6x protected 18650 batteries connected in series to produce 24V, and then all the packs are connected in parallel. The amplifier powers a ...
17
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8answers
6k views

Smooth switching between 12 V batteries, with a toggle switch

I have a number of instruments (12 volts, drawing a few hundred milliamperes) that occasionally need to be switched between one of two 12 volt lead acid batteries. The toggle switch is break-before-...
0
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0answers
23 views

Voltage drop on system activation

My question is generic in nature about electronics system design. I am trying to put together an RC car which is powered by an AVR Atmega168 chip. It communicates through an HC-12 module and has a ...
0
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0answers
10 views

Double A battery & lithium battery charging way

I do have some question regarding the charging input for nimh double A battery & lithium battery. Is it possible for my 7.4volt lithium battery charged with 8.4volt 2Ampere charger? Any idea on ...
3
votes
3answers
131 views

Why does there flows no current through the common part of the circuit?

I saw there was a post asking the same question here but I still don't understand it. I am reading the book Code: The hidden language of computer hardware and software and the book shows the ...
0
votes
1answer
60 views

Battery charging over USB-C (using USB-PD?)

I'm designing my first PCB, a wireless Keypad/Macropad with a battery. I'm probably going to be using a 2Ah Li-Ion battery because there will be a lot of LEDs on it and I just want it to last longer ...
3
votes
2answers
569 views

Replacing NiMH with Li ion [duplicate]

I have a rechargeable vacuum cleaner with NiMH batteries, 1800mAh and 14.4 volts, 12 cells. The charger is 18v 200mA. The batteries have now died. Can I replace the batteries with 4 cell Li-ion in ...
0
votes
2answers
45 views

Why would a BMS (or other circuit) have reduced voltage after a short?

I have this 9Ah 42v battery pack protected by a BMS wrapped in a shrink which I would rather not disassemble (so I don't currently have access to BMS' circuit). It has two wires for charging, and two ...
0
votes
3answers
30 views

Ideal Battery in Circuit

Does Kirchoff's voltage law hold when we connect a single battery to a circuit that has no other components. If it does hold, kindly let me know how. If it doesn't, how do we reconcile with that?
0
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4answers
77 views

No potential difference between the negative terminal of battery A and positive terminal of battery B?

I know that if you have two batteries, battery A and battery B, and connect the negative terminal of battery A to the positive terminal of battery B, there is no potential difference. If you consider ...
0
votes
1answer
60 views

Smartphone battery: safe for (further) use? [closed]

I disassembled my smartphone, which required removing the (non-removable) battery. The battery was glued with double-sided adhesive tape to some housing on the board. Further, there was some 'metallic'...
0
votes
2answers
52 views

Using a 12V battery while simultaneously charging via Heavy Duty battey charger

Very similar to a question asked and answered but using solar panels.. BUT this time I'm asking, Can I use my 135Ah deep cycle battery to power a 2000W inverter and at the same time charge my battery ...
0
votes
1answer
23 views

MB85RC256V for data logger sensor project?

Please. I need somebody can tell me if I can replace a SD card module of arduino to use instead a MB85RC256V fram module 32KB. I want to save power of 3.7 battery, but I am not sure if I can use a ...
1
vote
2answers
74 views

Circuit to tell Microcontroller when Voltage is Low

I would like to trip an input, similar to a button input to an microcontroller if the input voltage to the circuit/microcontroller is below a certain threshold. I have transistors and some zener ...
0
votes
0answers
36 views

BQ2002, LM317 NiMH charging circuit. How to control the current output?

I have designed a charging circuit utilising the BQ2002 and LM317 for 2x 1.2V NiMH batteries, and it is to be charged using a 5V USB input, I need the output current to be between 550 mA and 1A. I ...
1
vote
1answer
66 views

Turn on a device if voltage drops below a configurable level?

Consider a Li-Po battery that has to be protected from damage by going below 3V. What would be the easiest, lightest, smallest ways to e.g. turn on a warning LED or buzzer (using the same battery ...
0
votes
1answer
70 views

How much battery power for LED and how to make it flicker [closed]

I am trying to figure out what configuration of battery(ies) I need to power this LED. I am only using one (specifically the warm white 1-up). I am also looking to make it flicker like a candle with ...
0
votes
1answer
79 views

Comparator loses voltage when connected to mosfet

I want to make a discharger for 18650 batteries so I can store them at a specific voltage. I built a comparator (LM393) with a voltage reference to 3.8V at the inverting input and the voltage of the ...
6
votes
2answers
237 views

Can the negative impact of mixing new and old batteries be mitigated?

Mixing old and new batteries is bad. But there are various options how they can be mixed, and I guess there are use cases in which certain ways of mixing can be justified. In my off-grid solar ...
-2
votes
1answer
45 views

battery fully discharging [duplicate]

My goal is to use my laptop, a pioneer dj controller and 2 krk rokit 5's (50W class-AB amplifier boxes) for a party all at the same time for about 6-8 hours in a place without access to grid power. ...
-1
votes
1answer
33 views

Using a 7.4 V LiPo Battery for an Arduino Feather 32u4

I am working on an Arduino project at the moment, with the following board: Adafruit Feather 32u4 And it says I need 3.7 V of LiPo to power it. However I also have a valve that I want to open and ...
0
votes
4answers
75 views

How to reduce the current of a battery with an unknown maximum amperage

I'm currently trying to heat a wire to a certain temperature and tests showed that the amperage needed is in the range of 3-4 A. However, I'm having a problem with how to supply such current to the ...
0
votes
1answer
44 views

Charging a L-ion battery 3.7V/850mAh with terminal connectors

How do I charge a battery with a connector as shown in this link: https://uk.farnell.com/bak/lp-503759-is-3/battery-lithium-pol-3-7v-1300/dp/2077882?MER=bn_level5_4NP_LastViewed_1