Tagged Questions

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
40 views

Are there any high energy density (i.e. zinc-air or lithium-manganese dioxide) batteries without high internal resistance?

For my wild life camera, I want a small cell that can provide 0.5W for 8 hours or more. It doesn't seems rechargeable lithium ion batteries have that energy density. I don't mind if the cell is ...
1
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1answer
40 views

Switching between USB power and single alkaline battery

I've read the numerous other questions addressing this topic, but I'm not sure if any of them apply to my situation. I am designing a device that will run off a 3.0-3.3V supply voltage and draw no ...
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2answers
45 views

Why are different currents used for charging batteries with the same voltage output?

I'm trying to understand the behavior of batteries a bit more. I've noticed that chargers for given batteries have different current capabilities. Do batteries need to be charged with a voltage that ...
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0answers
40 views

Battery monitor for LIPO batteries [on hold]

I bought a battery monitor for my LIPO pack. The model is this one https://www.hobbyking.com/hobbyking/store/__6589__Battery_Monitor_2_6S.html My question is can I leave it attached to the battery ...
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3answers
59 views

creating mp3 device playing sound in specific time

I need help with creating device that will be able to play sound (can be recorded or from mp3/wav...) at certain time, for example at 8:00PM, 8:15PM; 8:30PM ...until 5:00AM. Device must be powered ...
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0answers
42 views

battery charger using pic [on hold]

i designed a 6V battery charger powering from solar panel. I'm using pic16f73. The whole circuit is powering from either solar panel or 6V battery itself. Battery voltage and panel voltage are ...
2
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1answer
41 views

Bi-directional High-side NFET switches — drains or sources connected together?

TL;DR: When using two N-FETs to implement a high-side switch should the FETs be arranged so the drains are connected together, or the sources? Some additional facts about the current design: 1) A ...
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3answers
129 views

May I power atmega32a-pu microcontroller from AA batteries?

I need to provide +-4.5V to the microcontroller. That would be fine by having 4x rechargable batteries, but how is it with current? On each AA battery is written min.2550mAh. I am not sure but I think ...
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0answers
46 views

monostable 555 current is bleeding, battery dies

This is likely an obvious question to an electrical expert, but I am only doing my best. My monostable 555 project is currently working: when triggered, an LED gets 5V and stays on for 5 minutes. ...
0
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3answers
74 views

Can I just connect two CR2032 batteries in parallel?

I'm designing a device with a small current draw that will mostly sleep in a very low power mode and I need to use button cell batteries due to a limited thickness. I would like to double time between ...
2
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2answers
220 views

Li-ion Battery - Constant Charge

I have system that 98% of the time consumes less than 300mA. The remaining 2% it consumes 550mA. It is a USB system and works with a PC. I have looked at various options to stay withing the 450mA ...
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2answers
65 views

voltage drop when using voltmeter

it's a theoretical question. is there any voltage drop when measuring a 12v battery with a multimeter(voltmeter mode)? so if we get 12 Volts reading near the battery, does this changes if we extends ...
0
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1answer
40 views

Running a load off a solar panel connected to 2x 12V batteries.

I am having trouble figuring out what relay I should be using for my solar panel set up. I have a solar panel running to a solar charge controller. I then have the controller running into a relay. ...
0
votes
1answer
42 views

Effects of C Rating on Battery Life

A polymer lithium ion battery is rated at 3.7v, 6600mAh and a maximum discharge current is specified at 3.3A. I take it this means the battery can be discharged at 3.3A and last for two hours since ...
0
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1answer
43 views

Battery dimensioning

For a school project I'd like to put a "fit pc 2" (a RaspberryPi-like) on a flying device. As the fit PC2 is supposed to be directly plugged to energy, I'd like to buy a battery to let it work in ...
1
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2answers
69 views

Replace 12V 5A power supply with battery

I am buying a rgb led strip with the following technical details: Voltage: 12 volts Wattage: 60 watts I want to connect this strip to a battery and don't know ...
1
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3answers
181 views

Direction of current through a circuit with multiple batteries

So I've got a bit of a problem trying to understand this circuit in my physics book. If current flows in the direction of the three arrows (I1, I2 and I3, couldn't find a way to name them) how can ...
0
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1answer
95 views

9v battery to parallel 3v LEDs - burnout

I'm having an issue in a simple (n00b) LED circuite - ended up burning out a couple of LEDs due to some mistake I'm making, but can't figure out what the error is. I've got a 9v battery, trying to ...
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2answers
51 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 ...
1
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1answer
47 views

Why are the charge and discharge rate of Lihium Polymer Batteries different?

I have a 3S 1.3MAH Lithium Polymer battery with a 25C discharge rate, and a 5C charge rate.From what i know, the discharge rate is the rate at which the battery can be safely ischarged( i.e how many ...
5
votes
3answers
417 views

What should I use for powering a Raspberry Pi at near space altitudes?

I'm planning a high-altitude weather balloon project (to around 100000 feet) some time down the line to take video and pictures of near space altitudes and I have some questions I need to ask before ...
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2answers
84 views

How much current does a typical multimeter draw to measure resistance?

Assuming it's running on a 9V battery like most multimeters are, and the setting is on MegaOhms. How much current will be drawn from the internal battery?
0
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0answers
55 views

Is it plausible for this battery to charge 32% this quickly?

So my phone ran out of charge earlier. I stuck it on charge and turned it on. 5 minutes later I came back to it and the screen said that the battery was 32% charged, which seemed a bit odd to me. So ...
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2answers
50 views

Low voltage cut out switching for a 6v input SLA to 5v output circuitry - or alternative ideas

I am currently modifying a wireless video door phone system with remote door release system, for use with a walking frame, for my elderly mother in-law, who lives alone. The 7"monitor runs a 5v 1a DC ...
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1answer
75 views

Charger light circuit [duplicate]

I have a charger light. It gets charged by 220V AC supply. It can light 5 LEDs. I know that it needs to make the supply 220V AC to DC of lower voltage nearly 5V to 10V. Then it can charge the small ...
0
votes
1answer
54 views

Relation between C-rate and power of a battery

I'm a non-engineer, but I need to understand the function of a battery. I hope you can help me! For example, I have two bulk storages. 5MW (power) 5 MWh (capacity) 5MW/10 MWh So the definition of ...
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3answers
104 views

When is the AA battery voltage drop?

I have a device which is running on two AA Duracell batteries. The batteries (brand new) together is producing 3.2 volts (1.62 volts individually), which is estimated to run for at least 2 years. The ...
1
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1answer
49 views

NI-MH battery monitor design. Any obvious errors?

Let me preface this by saying I'm not that much of an EE expert, this is a "hobby" project, I consider myself as knowing enough to be dangerous. ;) I'd never apply for a full time career as an EE ...
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0answers
21 views

Controlling ESC with Arduino [migrated]

I want to control these motors: hexTronik DT750 Brushless Outrunner 750kv with this battery: Turnigy 2200mAh 3S 25C Lipo Pack and these ESCs: TURNIGY Plush 18amp Speed Controller. I am new to this ...
0
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0answers
28 views

Adding Battery amps [duplicate]

Can you get more amps out a bank of batteries with different configurations? I know that if you put batteries in series you add their voltage, so you have more electrical pressure. And if you put ...
0
votes
1answer
69 views

Low-power dual-rail ADC

I am building a battery monitoring device and planning on measuring voltage drop across a current shunt, amplifying, and reading into an external (12-bit) ADC chip to get a value of the resolution I ...
0
votes
1answer
88 views

What battery to choose with motors?

I am trying to figure out how many batteries I will need, in order to power my 4-wheeled robot (based on an Arduino). I understand that it is not practical to power the Arduino and the wheels with ...
0
votes
1answer
57 views

Charge condition of lead acid battery

I need to monitor the charge condition of an 8V lead acid battery. For monitoring purposes, I used a Beagle Bone Black running Linux. It is also supplied via this battery. The battery also supplies ...
0
votes
1answer
55 views

Short-circuit xPyS LiFePO4 batteries

I have a LiFePO4 battery connected in 2P4S configuration. What happen if one of the batteries is short-circuited? The other batteries will also be short circuits, or this will be result in the venting ...
14
votes
1answer
435 views

Battery (Li-SOCl) voltage varying with orientation

We are using this 3.6V Lithium battery (ER14505) to power the micro controller circuit in one of our devices. The device is capable of reporting the battery level. Since the controllers brown-out ...
0
votes
1answer
72 views

LiPo protection circuit IC

I'm making a power board for my robot and I am looking for some advice regarding LiPo battery protection ICs. I might need to draw a fair bit of current (9A), though if I get the programming right, ...
0
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0answers
35 views

How to use Mifare RC522 RFID card reader without mains power?

I want to make a simple home security system. I'd like to be able to have an RFID card reader near my door. All members of the family will swipe in and out, and when everyone is out, the web cams will ...
0
votes
1answer
104 views

Connecting batteries in parallel (concerns)

I have been trying to understand if it is possible to connect two identical batteries in parallel (same: number of cells, manufacturer, capacity, CRate, usage). I want to create a circuit to select ...
0
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0answers
37 views

Difference in self discharge rate between Lithium iron phosphate battery vs Lithium Polymer Battery

What is the difference in self discharge rate between lithium iron phosphate battery and lithium polymer battery? I have a remote application in which the self discharge rate matters a lot.
1
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2answers
67 views

Shape Memory Metal framed sail

I am working on a costume prop that utilizes a triangular cut sheet of emergency blanket spined with a single 12" long, .04" dia piece of nitinol wire that has a transistion temp of 115deg F. My plan ...
1
vote
1answer
38 views

Difference between Lithium Polymer batteries of varying capacity and cell amount

I was looking to purchase a LiPo batteries online for a side project. Upon shopping around, and reading up on LiPo batteries, I have a fair understanding on what the numbers/letters on the battery ...
1
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0answers
60 views

AGM Batteries: Comparison of Auto to Marine

Research (links go through to the actual product descriptions, for those who read specs): Diehard AGM Auto Group 34 775 CCA: $153 Diehard AGM "Marine" Group 34 880 CCA: $250 West Marine house brand ...
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2answers
85 views

Low noise voltage regulation

I have a circuit which currently runs off of either a 12VDC wall wart adapter, or it falls back to a 9V battery if the wall wart adapter is not connected. My circuit currently uses a chip which ...
0
votes
3answers
89 views

Low battery level circuit - Changing “trigger” level

I am re-creating a simple low-battery level circuit that turns on a low-power LED to indicate that the battery needs to be changed. The circuit is shown below. There are two things I would like to ...
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votes
0answers
58 views

Which would be the safest battery type for a wearable electronics?

Which battery chemistry is most suitable for a wearable electronic gadget like a wrist band? I wanted to consider safety, and potential power (mAh etc)? I know there are the new "flexable" batteries, ...
3
votes
3answers
452 views

Automatically switching from 9V battery to DC wall adapter on insertion

I have a simple circuit that runs off of a 9V battery. I'm re-designing it so that it can also run off of an external 12V DC source (ie: a wall adapter). I want to design the circuit so that if both ...
1
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0answers
38 views

Li-SoCl2 battery state of charge

I'm developing a data logger powered by Li-SoCl2 (http://www.100y.com.tw/pdf_file/02-SAFT-LS33600.pdf) battery and I have no idea on how to overcome the problem of estimating the residual charge of ...
1
vote
1answer
70 views

How big should battery be to power two strips of led for few hours?

I have an idea for halloween costume for upcoming Halloween. It will involve building two small sets of infinity mirrors. I am completely new to the electrical engineering. The infinity mirrors ...
4
votes
2answers
368 views

What is a safe max. discharge rate for a 12V lead acid battery?

I've got a 12V 2.4Ah lead acid battery which I plan to connect a water pump to. I've looked at various pumps, but the one I'm most interested in draws 2.2A. I'm not so interested in how long the ...
2
votes
2answers
112 views

Battery Charging Circuit - NiCd

I am designing a battery charging circuit for an in circuit NiCd battery (used on a RC car). From my research I understand that I need to charge using a constant current source, and for fast charging ...