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0
votes
2answers
57 views

EMF transmission from cell phone's battery

According to Cell Phones & Wi-Fi―Are Children, Fetuses and Fertility at Risk? While one can put the phone in ‘airplane mode,’ which disconnects it from Wi-Fi and the Internet, the cell phone ...
1
vote
1answer
19 views

Cell Voltage Relaying in a Battery Management System

Question: If I have 48 lithium cells connected in series as a pack, how would I best go about physically implementing a system to measure, isolate, and relay cell voltages to a centrally managed ...
0
votes
1answer
51 views

MOSFET Cell Balancing Circuit

I'm designing a simple cell balancing for charging LiPoFe4 cells in series. In order to prevent overcharging, when on of the cells reach the maximum charing voltage, the microcontroller will enable ...
0
votes
0answers
40 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
vote
1answer
48 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
votes
1answer
89 views

TLV431 as direct replacement of zener?

The answer here suggests using strings of suitable zener diodes to drop the cell-voltages of a battery stack down, to measure the individual voltages by standard (that is non-high voltage) ADCs. The ...
1
vote
1answer
60 views

Simple questions about Battery network

I have a question related to small battery connections. I am working on a project where the design has to be kept as small as possible. I need 3.3V regulated supply and run two small coin vibration ...
0
votes
2answers
5k views

Are AA battery and 18650 battery the same? [closed]

I have an Antex SZ004W0 wireless soldering Iron which uses three 1.5V, AA batteries, but I don't know if it supports rechargeable batteries. I know that it supports non-rechargeable battery named ...
0
votes
2answers
282 views

laptop battery cells measurement [closed]

I have two dell laptop Li-on batteries (J1KDN, 11.1 V Capacity 48Wh, Min 4.2a). One battery seems to loose its charge very fast and the second one just turns turns off around 70% (with no warning). ...
-1
votes
1answer
315 views

How to hack a battery powered device to use 1 Li-ion cell instead of 2 NiMH cells?

I want to hack a cordless computer mouse, so it can be used with 1 lithium ion cell (standard cobalt cathode to be extra precise) instead of the intended 2 nickel metal hydride cells. The main reason ...
2
votes
2answers
144 views

Alkaline cells vs. LED flashlight

I have (had, actually) an El Cheapo pocket LED flashlight powered by 3 AAA cells. It was shipped with very low quality "salt" cells (regular, low weight - someone please suggest a proper English name ...
-4
votes
1answer
880 views

Battery replacement on laptop [closed]

In my way to replace my laptop battery, I have question about compatibility. My old original battery has the following information: Li-Ion, Rating: +10.8V ~ 4400mAh, 48Wh The battery slot on my ...
5
votes
1answer
107 views

Is it ok to power several op amps with the same pair of 9V cells?

I'm experimenting for the first time in the wonderful world of operational amplifiers. I'm processing signals in various ways - amplify, envelope detection, voltage differences, voltage-to-current, ...
9
votes
1answer
1k views

Arduino: Measure external voltage

I have a "problem" while trying to measure the external voltage from a coin cell. I have simplified my circuit, but basically I have a DS1307 real time clock powered by the Arduino 5v output, and a ...
-1
votes
1answer
807 views

Charger specification of 3000mah battery

I am planning on making a USB charger for my Tablet whose battery is of 3000mah. What should be the output current and voltage required for the charger? Is there anything else other than the output ...
2
votes
2answers
137 views

AA cell for low power embedded system -Debugging help needed

I am using AA LI cells for an embedded system project.This is a low power embedded project with various modules consuming current in pulses. Recently one of the prototype board stopped working. ...
19
votes
3answers
5k views

How is wristwatch with 10 years battery life possible?

Turns out Casio offers a handful of wristwatches with "10 year battery life". The claim is that thanks to "an advanced technology" the battery life in those watches is extended to ten years. Now if ...
3
votes
3answers
876 views

Coin cell battery for Bluetooth?

I'm trying to determine which battery to use for my application. I'll be using a class 1 or class 2 Bluetooth (not low energy) module, which requires about ~50/60mA of RX/TX current. In addition, ...
2
votes
2answers
2k views

Consequence, effects and solutions - mobile-phone always connected to AC power

Would like to ensure that a mobile phone is always charged, without requiring manual intervention (s.a. disconnect/reconnect charger, switch on/off charger etc.). One thought is to put the phone ...
1
vote
3answers
5k views

Energy consumption when cell phone charger connected to socket but not to phone [closed]

When my cell phone is charged fully, it says 'Please remove charger from wall socket to save energy'. How am I wasting energy if the charger is connected to the socket but the phone is not connected? ...
0
votes
1answer
491 views

How I can to reduce 9V battery to 7.4V - it is for R/C model [closed]

What size of resistor I can use to reduce the 9V rechargeable battery to 7.4V output for R/C model please? I would like to use rechargeable 9V batteries instead of 7.4V as it´s handy to go a grab one ...
0
votes
1answer
376 views

Using old notebook battery to power electric screwdriver

I have: Dead notebook with live LiIon battery (HP HSTNN-CB50): 14.8V, 8 x 2500 mAh 18650 LiIon cells. Rated at 73 Watt-hour. I haven't managed to open the battery pack yet, but it's clear from the ...
1
vote
2answers
343 views

msp430 and LiFePo4 cell as supply

I want to use a LiFePo4 cell as a supply for the msp430. For this purpose TI developed the TPS61221. I'm wondering if that's really needed if I can guarantee that the cell voltage is between 2 and ...
3
votes
7answers
669 views

Effects of Pulsed vs Direct Current on Battery Depletion

I'm doing some work with a portable, cell-battery-based electronics and someone on the design team mentioned that pulsed current will more quickly deplete a battery than constant current, even if both ...
8
votes
3answers
1k views

Memory backup capacitors: why a capacitor?

Why would an engineer choose a memory backup capacitor instead of any of the types of rechargeable batteries available? Their energy density seems far poorer, and they can't hold their charge very ...
0
votes
6answers
5k views

How to charge Laptop Li-ion Battery cells manualy?

I have received some Li-ion batteries which were originally used in Asus A2 Laptop battery original one and I would like to know if it is possible to charge each cells independently with some device ...
24
votes
3answers
3k views

Are coin cells a suitable replacement for AA batteries?

I am currently using AA batteries in my projects but would like to look at cell batteries for my next project, due to their compactness. Apart from the physical appearance, how do cell batteries ...