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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14 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. ...
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1answer
39 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 ...
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1answer
41 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 ...
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2answers
59 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 ...
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3answers
178 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 ...
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22 views

Apple iPhone 6 battery [on hold]

is it true that all cell phone batteries only have one cell each? Particularly want to know if Apple iPhone 6 battery has only 1 cell.
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1answer
91 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
48 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 ...
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0answers
27 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 ...
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3answers
407 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
78 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?
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54 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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46 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
73 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 ...
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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
101 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 ...
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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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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 ...
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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 ...
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1answer
66 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 ...
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1answer
86 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
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1answer
56 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 ...
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1answer
54 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 ...
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1answer
430 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
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1answer
67 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, ...
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34 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
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1answer
102 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 ...
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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.
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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 ...
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1answer
37 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 ...
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0answers
58 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 ...
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3answers
81 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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57 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, ...
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3answers
444 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 ...
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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 ...
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1answer
60 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
361 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
108 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 ...
11
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2answers
862 views

Why don't we get shocked when we touch a car?

According to this answer to a question about car batteries: [...] so the entire chassis is an extension of the minus terminal of the battery. If this is the case, I would expect that you'd get ...
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1answer
50 views

How to charge an iPad for maximum battery efficiency [closed]

iPhone chargers provide 5W of energy while iPad chargers provide 10W of energy. If you plug an iPad in an iPhone charger it will charge slower than normal. Also, there are many computers which provide ...
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3answers
67 views

Figuring resistor wattage and value

I have a remote controlled airplane that I am putting LED lights on. The power supply is a lithium polymer battery that is rated at 22.2 volts and 4000 miliamps. I have an LED that is rated between ...
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2answers
105 views

Where does power in my laptop go when I disconnect the battery? [closed]

I have a laptop which, when put to sleep, sometimes enters a state of limbo, from which it can be neither turned off nor on, and the only solution is to disconnect the battery, reattach it, and turn ...
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3answers
95 views

How long would an original gameboy last on a modern lithium battery? [closed]

The original Gameboy was famous for it's battery life on 4AA batteries. My HTC One smartphone can last about as long as the GB did back in the 80s. So how long would an original gameboy last if ...
0
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1answer
64 views

LiFePo4 2 Cell Series Charging with MCP73223

I want to make a charger for two LiFePo4 cells in series. As I'm aware, charging cells in series may be problematic, due to slight differences on each cells, that may charge one and not the other, ...
0
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1answer
99 views

Is it okay to put a solar cell and battery into resin?

I was thinking about making a simple circuit with LED, solar cell and battery and put it in resin mold to make it weather proof. I wonder is there anything wrong (chemically) with putting a battery ...
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3answers
133 views

Are control systems and motors typically driven from the same source in robotics projects?

My control system is a simple microcontroller between 3.3V and 5V, but the stepper motors I require are 12V. I have ordered a 14.8V battery that I intend on regulating down to 12V to drive the motors, ...
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1answer
48 views

Flash Bulb battery depletion

Extremely simple question for you. Probably beneath all of you to answer apologies for that. My camera's flash is rated in Watt seconds. My battery is rated in mAh . If my battery can output 1000 ...
4
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2answers
149 views

What are the use of these diodes?

I have a circuit diagram which is for a circuit used for testing batteries under a load, only one of the batteries can be tested at a time and I was just wondering what the point of the diodes in the ...
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1answer
69 views

NiMH battery charger using discrete elements

Below is a schematic of NiMh battery charger that must automatically switch off charging current when battery is fully charged. I am aware that the main part of this scheme is current source, build ...