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5
votes
2answers
499 views

5 year run time on small battery

I am working on a project that checks a sensor every 12 hours and reports the status via cellular modem to our server .. Power consumption is less than 1mA during sleep mode and spikes to 900mA ...
0
votes
3answers
68 views

Why wont my 3volt LED light up with two 1.5volt Batteries?

I have two 1.5 Volt batteries, a Red 3V LED, and some cables. The batteries I have connected in series like +- +- From my studying I believe I should now have 3 ...
0
votes
1answer
88 views

12 Volt Solar Air conditionair

I saw a post on YouTube where somebody was able to make ice with a 90 watt solar panel, two 12 volt batteries, an ice maker (800 watt spikes) and 1000 watt DC-AC inverter. ...
0
votes
0answers
23 views

How to determine load to use in a battery discharge curve

I am making a discharge curve of a battery I am testing. So for the discharge curve, what load should I use? (This was kind of answered here, but it was kind of a guess in that the load is based on ...
1
vote
2answers
67 views

How to charge an AGM battery fast?

I have a 12V, 200AH AGM battery. The maximum charging current recommended by the manufacturer is 50 amps. Now, I need to connect two AGM 12v batteries in series to connect to the input of my 24 volt ...
1
vote
1answer
79 views

How to calculate solar panel setup?

I have an equipment which draws 550W at a constant level, no peaks. I want to power this unit with solar cells only during the day when there is light using a simple car battery. Because I don't want ...
-3
votes
1answer
69 views

LM386 with power bank [closed]

I made a guitar amp using the LM386 and i power it with a power bank and a sparkfun usb breakout board but the power bank shuts down by itself after 20-30 seconds. I read it's because the circuit ...
1
vote
1answer
64 views

Discharge and Recharge of a battery [closed]

Under which value it is not recommendend to discharge a Li-Ion battery? How fully discharging battery affects a battery life? What happens if we leave a battery on charger, even battery is fully ...
0
votes
1answer
58 views

Laptop battery not working after cells replacement

I have a Sony VGP-BPS21A battery that I use to power my laptop on. It is really old, like 5-6 years now and its cells have lost more than 50% of their capacity. As a new OEM is very expensive, hard to ...
0
votes
2answers
32 views

Use a li-ion battery at two different voltages

I scavenged a li-ion battery from a broken laptop. It is made of 6 Samsung ICR18650 cells (3.75V 2800mAh), parallels two by two so that the total pack is in fact the sum of 3 cells at 3.75V, so 11.25V ...
-5
votes
1answer
155 views

How many hours would a 38000 mAh powerbank will last? [closed]

i bought a 38000 mAh powerbank and to my surprise when I could only use it for a total of 6 hours and then I have to recharge it again. My battery's capacitu is 1 700 mAh. By the way I'm taking up ...
0
votes
2answers
99 views

Can someone explain the battery management schematic for the following robot?

This seems like a good start to build my own battery management system. Can someone explain how exactly is this circuit working? See link for full size image. Link to Full Size Image Link to Robot ...
0
votes
2answers
134 views

Estimate minimum discharge voltage in a laptop battery

The objective is to determine the best 18650 cells to replace the ones in my laptop battery. To do that, I need to know the minimum voltage the battery controller accepts before ordering the OS to ...
0
votes
1answer
124 views

How to turn-on laptop's battery pack after replacing cells? [closed]

After a few years of use, my battery pack finally died. The laptop doesn't even detect or try to charge the pack anymore. So I replaced the cells in the pack for new ones, but that didn't make it to ...
5
votes
6answers
2k views

How to calculate the maximum current a AA battery can deliver for a short period of time?

I want to measure the maximum current a AA battery (full charged) can deliver for a short period of time (let's say one second) I have in mind to do this with a multimeter : setup multimeter to ...
0
votes
0answers
24 views

What is the relative mass of a LiPo cathode?

Relative to the mass of a LiPo battery cell, how much is the mass of the cathode? That is, what is the percentage-mass of a LiPo battery's cathode?
1
vote
1answer
87 views

If I have three button cells in series, and one of them dies, will the whole circuit still function at a lower voltage or will it stop flowing?

If I wire three button cell batteries in series, their voltages should be summed. Now, if a battery dies, let's say BAT3 for the sake of example, will the circuit ...
0
votes
2answers
751 views

What is a dead battery cell, what causes this to happen, and what are the implications?

Today I had a bit of car trouble where the culprit turned out to be the battery. I had driven my car just 5 minutes earlier without issue, but upon attempting to crank the vehicle it made a final ...
0
votes
1answer
60 views

DIY power 230v filament bulb off grid [closed]

I need to power a 230v bulb off the grid via solar power. Typically, I would have solar panels that charges some 12v dry/wet cells. These cells will have to supply an inverter that would power the ...
0
votes
2answers
102 views

avoid Li-Ion batteries explosion

As a student group project, we are going to use Li-Ion batteries to test our charging and balancing circuit. These batteries at risk of explosion. How should we avoid that danger? Is there any ...
0
votes
3answers
907 views

Replacing 18650 cells in laptop battery with greater capacity ones

My laptop battery died and I can't find a replacement (old laptop) so I'm going to need to replace myself the 18650 cells it has. It is an 8-cell battery (a series of 4 banks of 2), making the whole ...
0
votes
3answers
105 views

why does the model s use multiple batteries?

The Tesla Model S and NASA's Robonaut both use a battery pack that consists of an array of hundreds of battery cells. Why don't the engineers just create one giant cell?
-1
votes
1answer
91 views

Fast rising voltage on lead acid battery while charging

i have a couple of 12V sealed lead-acid batteries.Whitch i have to charge.But when i hook one of them on the charger at 12V/1A (the battery is 10Ah) the voltage from 12.6 drasticly increases up to 14V ...
5
votes
4answers
496 views

Developing BLE device. Questions

I am designing a bluetooth low energy device. It basically reads a sensor over I2C and collect data. You can check data in your phone whenever you want. I have two questions, one related with antennas ...
0
votes
2answers
123 views

Are BLE modules capable of working with a CR2032 battery? [duplicate]

I keep reading that the Bluetooth Low Energy modules are capable of working with a CR2032 battery for years, but their consumption is around 20mA and the max discharge of a CR2032 is around 3mA (200uA ...
7
votes
2answers
278 views

Connector Problem. How to conveniently connect with cell-phone LiPo batteries

Using a LiPo battery from sparkfun is easy as it comes with a molex connector on it. But how to conveniently connect to a LiPo battery taken from a cellphone? Soldering doesn't work on the exposed ...
1
vote
0answers
63 views

Is lithium ion battery sutaible for all terrain vehicle

I have manufactured an all terrain vehicle.Is li-ion can sustain in the jerking of car,if battery is fully packed and waterproofed.If not,which battery should i use? Can i go for Li-polymer battery? ...
-1
votes
1answer
78 views

Doubt regarding Combination of Cells

I was unsure of what the voltmeter would read: the terminal voltage of the top cell, or the voltage across the parallel combination of cells. I tried calculating both ways, but both give the same ...
0
votes
2answers
97 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
38 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
167 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
2answers
247 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
141 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
117 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
73 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 ...
2
votes
2answers
30k 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
2k 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
407 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
162 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
1k 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
2k 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
1k 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
142 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. ...
23
votes
3answers
8k 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
1k 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, ...
5
votes
3answers
3k 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
11k 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
701 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
469 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 ...