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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2answers
32 views

Charging li-ion batteries with protection circuit

If i'm using a protection circuit like this one: http://www.batteryspace.com/pcbfor148vli-ionbatterypack5alimitwithfuelguagesocket.aspx and 4, 3.7v li-ion batteries. Can I use a simple 16.8v dc ...
0
votes
2answers
58 views

How to measure the current drawn by the radio and the headlights from car battery easily?

I wonder how much current is drawn from car battery when the headlights and the radio are fully open. Is there a way to measure the resistance of the radio or the headlights without unscrewing or ...
0
votes
0answers
27 views

Plugging battery backup and AC/DC converter into the same battery

Today, I took one of the UPS (UPS A) the battery out and directly plugged it to bigger 12V battery (so if the electricity is out it stays long). And I also have AC/DC 2000Watt inverter. That inverter ...
-7
votes
0answers
50 views

Creating a stunning device that causes no harm [on hold]

My son is hard to get up in the morning, so as a gag gift I wanted to make a low voltage low amperage stunning device to tease him with, but I don't want to hurt him. What size battery and capacitor ...
0
votes
1answer
54 views

What is the maximum voltage of a Lithium Ion Battery

My question is about the maximum charge voltage of a Lithium-Ion cell. I have charged my battery pack with 8.4V (the maximum voltage). The pack is a Samsung ICR18650-26F. The pack has a smart ...
1
vote
1answer
58 views

using android to power a PIC board

I have a PIC board that I want to power from my mobile phone when the phone is on and keep the phone topped up from a solar panel. I think I want to: access battery terminals in phone directly ...
0
votes
2answers
93 views

Options for 12v battery pack with charger

I have an amp that requires 12-20v dc power. I'm looking into a solution for a portable battery pack that I can charge while running the amp as well with discharge and overcharge protection. This is ...
5
votes
2answers
174 views

Relay not switching immediately from switching power supply to battery backup

WARNING This project as currently described is badly flawed in a number of ways that are liable to lead to complete failure of the equipment. As it is stated that it is intended to be used in a life ...
1
vote
1answer
98 views

What are the AC characteristics of a battery?

I'm planning on building a single cell AA NiMH battery charger and in the process I decided that I must also build a battery simulator to help me debug the charger. In my research, the best simulator ...
0
votes
1answer
60 views

battery balancing

I am using a balancing circuit for a 3S (3 series 11.1V) li pol battery. The chip I am using is the S8204B. I am unable to understand the datasheet properly. I have basically 3 components in my system ...
2
votes
1answer
58 views

getting more from batteries via series connection

Let's assume I have a 100W load. If I run this load on two 2000mAh 3.7V batteries in parallel then I should get a continuous run time of 8 min 53 seconds (given the 27 amp draw). However if I were ...
-4
votes
1answer
73 views

Convert 9v to 5V for IC vcc [closed]

Can any one give a circuit to give +5 V cc to IC 7473,please?
0
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2answers
69 views

Use battery voltage rating or fully charged voltage?

I am using a 3.7V (18650) battery, but its fully charged voltage is 3.85V. When calculating a resister for an LED circuit, do I use the battery's voltage rating (3.7V) or the fully charged voltage ...
1
vote
2answers
37 views

Is a NRTL / UL mark required for battery powered products?

We have a small 12VDC battery powered projector that uses a 5 watt LED to project an image through a transparency onto a wall Electrically it is equivalent to a flashlight. Does this type of product ...
0
votes
0answers
64 views

provide 3.7v source to android tablet

Android tablet mostly needed a 3.7V Lion battery to run on it. If I were to replace the battery with a power source, how can I provide such a 3.7V source from some existing products such as 220V/5V or ...
2
votes
3answers
138 views

Can I solder 4 AA batteries together in series and make my own rechargeable battery pack?

I've bought my young son a couple of remote control tanks for Christmas. They are supplied with two rechargeable 'battery packs' (4 x AA batteries heat shrunk together). The battery pack supplied is ...
0
votes
1answer
43 views

Requirements to power 3.5kVa inverter?

How many 200 Watt solar panels do I need to power a 3.5kVa 48DCV inverter for 24 hours if the load on it is 1500 Watts and the batteries are 200Ah, 12DCV each in a country with about 6hrs of sunlight? ...
0
votes
0answers
51 views

Safe temperature range for 18650 battery - powerful flashlight

There are many powerful flashlights, some of them have just one 18650 li-ion cell, 10W LED and they are very small. I have read few tests, I watched few video tests on YouTube and looks like some ...
0
votes
1answer
22 views

Mixing battery sizes [closed]

Apologies if this is the wrong Stack. I suspect this is a bit of a lowest-common-denominator question. I've got a cheap little Christmas tree covered in blue festive lights that takes 3 size-C ...
-2
votes
1answer
67 views

Max discharge rate of Alkaline AA batteries?

I'm in a bit of a tight situation, as I need a new battery pack for an upcoming competition, so I've tried to make my own. I put 7 of these: ...
2
votes
3answers
119 views

DC Questions and my understanding

Okay, we had a seriously bad science teacher this year, and long story short, we hardly understood anything relating to DC current(she was fired a few days ago). I understand Ohm's Law: Working out ...
0
votes
1answer
59 views

Turning a torch on or off using a single mini-switch

I need a circuit to turn on and off a torch, as given in the figure. The circuit must turn the output on when I press the mini-switch once, and turn the output off when I press the mini-switch again. ...
0
votes
1answer
75 views

How are these AA batteries 4500 mAh?

I found these two batteries in a drawer while looking for batteries for my wireless mouse. I was surprised to see that they are 4500 mAh, which is much higher than any AA battery I could find on the ...
0
votes
2answers
46 views

Toggle poles of DC using single port switch

I need to toggle the poles of a DC battery using a switch. can you make such a circuit for me? please ...
0
votes
1answer
65 views

How does battery charging work

I want to charge a 7.2V-2000mAh NiMH battery. I have many solar panels and a voltage regulator but I do not know what voltage is required to charge it. I've heard people say that as long as it is any ...
0
votes
2answers
75 views

AC vs DC and ELF - extremely low frequency

given : How do static fields differ from time-varying fields ? A static field does not vary over time. A direct current (DC) is an electric current flowing in one direction only. In any ...
0
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0answers
62 views

Supply for autonomous car with sensors and DC motors

I'll be using the Guibot Motorduino for an autonomous car project. This includes L293D motor driver and 7805 voltage regulator. The other components: Multi-Chassis - Tank Version with two DC ...
2
votes
1answer
165 views

How much current can you pull safely off a standard AAA battery?

This might be a stupid question. But how much current can you safely draw from a AAA battery. I am currently powering my project from a worktop power supply and it draws at 5V 0.45A during normal ...
0
votes
2answers
31 views

Battery Reserve Capacity - how do you determine lower load capacity?

I understand that Reserve Capacity is the number of minutes a battery can deliver a useful voltage under a 25A load. I have a 2A load and I'm researching the correct battery for my application. Is it ...
0
votes
1answer
50 views

battery charging

I have: -12V 7.2Ah,sealed lead battery,valve regulated -solar panel 12v with 100mA my question is,how long does it take to charge this battery by using this solar panel?
-4
votes
3answers
63 views

What is the maximum battery lifetime for a sleeping microprocessor? [closed]

I know it depends on the processor and the battery, I just want to know what's possible. [EDIT:] An example would be great!
0
votes
1answer
43 views

Maximum current draw from a step-up regulated output

I have a LiPo battery pack with 5V, 2.1A output. Now, let's say I boosted that with a step-up regulator like this Pololu module. At 12V output from the regulator, what is the maximum current I can ...
0
votes
1answer
26 views

Ah balance in different volt batt in series

I have added an electric motor kit to a recumbent trike. I'm using SLA batteries with a lithium ion 36v controller. Therefore the controller cuts out before the batteries are dead. I'm using 3 each ...
1
vote
1answer
50 views

Power a laptop LED backlight with NiMH batteries

I'm powering a laptop LED backlight with an external 24,8V power supply, because I have problems with the internal WLED driver. The display used to work at 27V, but with the 24,8V of the power supply ...
0
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0answers
41 views

Can I run a 3s ESC from a 12V power supply (car battery)?

I am building an ROV, and my thrusters will require 12V. The voltage source will be a 12V car battery. I have found this ESC and it seems to be just what I need (well over my ~9A draw and has ...
0
votes
3answers
101 views

Best kind of battery for electric motorcycle?

Sorry if this question doesnt belong here, I am new and learning. I want to try and build a DIY electric motorcycle, but am having issues finding the right batteries to use. I've tried searching for ...
2
votes
1answer
81 views

Making my own waterproof battery pack?

Today I had a bad experience on my cycle commute home from work - my battery pack died and I was left without a front light for 20 miles of my journey home. So I want to see about creating a new, ...
0
votes
1answer
83 views

Arduino standalone with 9V battery and accelerometer

I'm using an Arduino Mega for a project involving an accelerometer. Everything works fine when the board is connected via USB. When I use a 9V battery plugged in with the 2.1mm jack, values are ...
0
votes
2answers
63 views

About battery capacity and regulation

For a portable application, I would be using a single 3.7V 2600mAh li-ion cell. The circuit requires 2.5V to 5V to function with the current requirement being 100mA. So obviously a voltage regulator ...
0
votes
2answers
94 views

Purposely draining a battery by a resistor

I'm new to electronics and wiring, and wonder if a 15 ohm resistor will drain a 1.5v battery (specifically a Duracell Alkaline AA) in a reasonable amount of time to a super-intense white LED. Does ...
0
votes
0answers
60 views

How long will my ~20W device last with a 18000mAh battery?

I have a Mac Mini with a max power consumption of 85W but an average power consumption of ~20W (in my experience). I'm thinking of buying a portable power source with a 18000mAh battery. How do I ...
0
votes
1answer
145 views

Turn Laptop Battery to a Power Bank

Is it possible to turn a laptop battery into a power bank? I have seen video tutorials and articles on how to turn AA Batteries into power banks, however, no one has created a power bank using a ...
0
votes
1answer
55 views

Line-of-Sight method of simple code transmitting for outdoors

I'm trying to determine the best way to do this. Basically I'm trying to design a system that would transmit a signal containing a simple code to allow the receiver to identify the source device. It ...
0
votes
3answers
95 views

How can I fast discharge Li-Po battery?

I have a 11.1V li po battery (3S). I wanted to drain it fast so I could test a charger circuitry. How can I do that fast. Unfortunately, I do not have high current consuming loads which can drain a ...
1
vote
2answers
165 views

What type of batteries are these?

So, I can get these batteries very cheap - less than $2 a piece. However, I have no real idea how to use them. (I intend to power a robot with them if I can.) So this begs the question: what kind ...
0
votes
1answer
64 views

Can I connect directly a 3.7V 18650 li-ion battery to a mobile (cellphone)? [closed]

If I remove the 3.7V battery from my mobile, is it possible to connect to the battery +/- terminals a 3.7V li-ion 18650 battery?
4
votes
4answers
148 views

Calculating current draw from a battery using voltage and time information

Is it possible to work out the current or power a device is drawing/using, based on the following information: Maximum capacity of a battery (48 Ah) A table of voltage readings over time (starting ...
0
votes
1answer
80 views

Understanding Battery rating

I need clarification regarding the rating of the battery shown in the below figure. I know battery ratings are given in Ah(Ampere-hour), but here it is given A/s. The picture is from "Linden's ...
0
votes
0answers
32 views

Please help determining component specs of BQ76930 (BMS IC)

I was wondering if you guys could help me with some questions I have about the BQ76930 schematic (below, also found here: http://www.ti.com/product/bq76930 on page 42). How can I determine what ...
0
votes
2answers
73 views

Which is the best rechargeable 9v battery with high capacity? [closed]

I was looking for rechargeable 9v batteries with high capacity? I found "Energizer Ultimate Lithium - Battery 9V Li 1200mAh" on that site bellow. ...