Questions tagged [batteries]
An electric battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy
0
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1answer
33 views
Determining battery run time from Ah and MJ?
I am working on the following question:
Two 100 ohm resisters are in parallel across a battery. The battery can store 240 MJ of energy and is rated 240 Ah. The battery depletes fully after two hours. ...
-3
votes
2answers
67 views
Connecting different voltages in parrallel? [on hold]
why I musn't I connect different voltages in parallel? also actually why I can connect them in parallel if they are "equal" .. why is that correct?
Hi guys, why I musn't I connect different voltages ...
0
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2answers
89 views
Voltages in electronics
I'm wondering how exactly voltages are transfer between wires. I mean, once I've a voltage lets say 5v and I pulls from it a "wire" (not resistor) then at the end of the "dangling" wire itself the ...
0
votes
1answer
36 views
iPAQ Backup Battery Connector
I've used an H4155 on and off for about a decade now and every two years or so the backup battery begins to increase in standby voltage and fail. I prefer to replace it just for the sake of it ...
1
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1answer
30 views
LiFePO4 cells - self-balancing in series or parallel?
I am building various banks / packs from individual prismatic LFP cells, nominal 3.2V each. New and pretty large, 60-400AH.
I have a good power supply, charge each cell independently, Bulk stage CC ...
-3
votes
1answer
63 views
What should I look out for while buying an alternative battery for my mobile phone? [on hold]
I have a mobile phone, the battery of which is now dead. The specifications of the battery are as follows: 3.8V, Li-Polymer, 2500mAh, and 9.5Wh.
Since the manufacturer doesn't produce this battery ...
-3
votes
0answers
47 views
If my battery light comes on while driving and had a bad odor and won't start , what could it be [on hold]
I was doing my 200o 5 speed Nissan maxims with parking break, then battery and break light came on , then a odor came about . Pooped the hood and smoke was coming out and notice something fire red . ...
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2answers
23 views
How over-discharge protection function works on this circuit?
How this circuit to protect so call "over discharge"? since there's no output + and - terminals on the board and this case the load should connect directly to B+ and B- without any protection for ...
0
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2answers
47 views
hybrid vehicle DC voltage boost
if i join two battery cells in series then the voltage will be added. what if i replace one of the two battery cells with a DC generator?
My reason is because batteries (excluding Lipo) have modest C ...
0
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0answers
22 views
Programmable Charging controller for Li-ion/Li-Po [on hold]
I'm looking for a programmable charging controller (or set of ICs), that resembles laptop battery controllers. It will go inside of a battery pack with a small MCU and EEPROM.
Critical features:
0) ...
0
votes
2answers
46 views
Op Amp Output Voltage
I have a question about an LM741 op amp IC.
I am using the op amp as an comparator (open loop with no feedback), as seen below:
When the op amp output is low, the output voltage is still around 1.2v....
0
votes
2answers
52 views
How to use CC/CV Charger with a DC/DC converter
I am searching for a solution to charge a battery pack (7S1P)[ICR18650] with a charger with CC/CV mode and I have a BMS for protection (I've done research to maximise the security of the battery pack)....
1
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2answers
42 views
“Safe” (but slower) charge method for AGM batteries?
My understanding of AGM vs flooded lead acid (FLA) batteries is that FLAs like to gas/outgas but AGMs do not. It is pretty much a requirement to increase the charge voltage of FLAs so that they gas ...
9
votes
4answers
664 views
Allowable reverse current into Alkaline battery
Anyone know what happens to alkaline battery if a small current pumped in? For example 0.5uA into a 9V battery alkaline?
I want to add a simple 9V battery + rectifier as backup voltage to a 12v ...
0
votes
0answers
36 views
Hacking an eight cell battery monitor
My goal is to monitor each cell voltage of a seven cell li-ion battery and send this to a Linux board, specifically the Jetson TX2, over i2c. There does not seem to be any off the shelf component that ...
0
votes
1answer
43 views
charging 12v lead acid battery with OEM charger [closed]
I have an ExpertPower 12V 7 Amp EXP1270 Rechargeable Lead Acid Battery (link on Amazon here) and would like to safely charge it. Do you think this charger (Battery Tender 021-0123 -- link here) is an ...
3
votes
3answers
125 views
Long term car storage requires 2 batteries [on hold]
I store my second car for 4 to 6 weeks at a time. There is no access to electricity, so a battery tender is not practical.
The vehicle electronics slowly discharge the battery so it goes dead in a ...
0
votes
1answer
82 views
Switch module test circuit design
I am doing a project to make a test box that would to test the switch module in the photo below. Please see circuit diagram below for inside of the switch. Please note this switch is not an ordinary ...
0
votes
1answer
59 views
How to know when you've reached enough resistance for a battery?
Let's say I have a 1.5 V AA battery. If I connect its terminals together, that creates a short circuit which could make the battery catch fire.
How do I know I've added enough resistance to the ...
0
votes
0answers
33 views
What would be a good constant source of power for a motor? [on hold]
A couple of friends and i want to build an orrery.
We are having trouble in figuring out what would be a good power source for our motor. We are planning to use one motor to run the central gear ...
0
votes
3answers
56 views
Non electrical background trying to make a cool little custom project - Help please?
Brief bit of background - I've built my own PC's, I've repaired phones, changed plugs, fit light fittings from diy stores, and have a basic (very basic) understanding of electronics, but have found ...
-4
votes
2answers
136 views
Why the wave on a battery is neither square nor sine? [closed]
I’m measuring the electrical wave on a 1.5 V battery - why is the wave this particular shape? Isn’t it supposed to be sine or square? Thanks!
0
votes
1answer
26 views
LTC 4150 coulomb counter property
I want to monitor the capacity of a 7.4V, 2200mAH Li-ion battery. I have found a that LTC4150 coulomb counter can able to measure the battery capacity. So, suppose I have connected a fully charged ...
6
votes
3answers
826 views
Discharge time of 12 V 8.4 Ah at 5 mA
I have a motorcycle battery rated as 8.4 Ah (20 HR). It also says 8 Ah (10 HR) and I am not sure what the difference is.
Anyway, I have a GPS tracker fitted with a rated ...
0
votes
2answers
60 views
Calculate the Li-ion battery remaining capacity
How can I calculate the remaining capacity (exact or approx value) of a Li-ion battery by measuring its voltage. The battery is connected the load and i know only the battery voltage and the value of ...
0
votes
5answers
97 views
A basic question about amps, watts, and charging batteries
Why do we speak of watts (and not amps) when we refer, for example, to the "7.5W Wireless Charger for iPhones," but when we talk about cord-based USB charging, the specs typically refer to amps (and ...
1
vote
2answers
48 views
Problem understanding impedance measurement device accuracy format
I am reading the datasheet of an impedance measurement device. Its accuracy is listed as '±0.4% rdg. ±8 dgt.'. What does 'rdg.' and 'dgt.' mean? And how should I interpret the accuracy?
The device is ...
2
votes
1answer
97 views
Why are(n't) rechargeable batteries damaged by partial charging?
Over the years, I've come across websites and people with different opinions on the "correct" way to charge rechargeable batteries (I'm more concerned with laptop, tablet and phone batteries than with ...
8
votes
1answer
1k views
Is it normal for a lithium ion battery to read with a very low voltage on a multimeter?
I have a PS Vita and I suspect the battery is dead and needs replacing, as the Vita won't charge at all. But the issue could also be the charge circuit, as when plugging it in to charge the charging ...
0
votes
1answer
37 views
Rechargeable battery datasheet
Some parameters on the datasheet are a little bit confusing. What does the datasheet mean?
0
votes
0answers
26 views
Mounting Lithium Packs in Enclosures
I am planning to use a battery cell similar to the picture below in a product I'm designing. Is it ever appropriate to mount these directly on top of a PCB? (all components will be on one side of the ...
-3
votes
0answers
34 views
how do create a circuit that allows two power souces when one or the other is off? [duplicate]
I am trying to build a circuit board where the main battery power system is off and the temporary is used. Also when the main battery power is on the temporary is off. I want to turn my device on when ...
0
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1answer
55 views
Powering Arduino Uno with 9 V LiPo batteries
Would it be safe to use two 9 V LiPo batteries in parallel to power an Arduino Uno?
0
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1answer
31 views
Replacement battery voltage mismatch tolerance?
I want to try replacing a proprietary battery in an electronic of mine as a first electronics DIY project.
Thing is, the stock battery is 3.6V, and the phone battery I have on hand that I would like ...
-1
votes
0answers
23 views
Will PTC fuse work in this application?
So i have around 0.4A max current at 5V as output of a battery (step up converter output). Since what i am making is modular i need to give it protection against accidental mixup of output and input ...
0
votes
1answer
34 views
Battery switchover circuit when battery is being charged
I would like to use two LM5050 in a typical redundant supply configuration for wall adapter and a battery. My concern is that when wall adapter is connected battery voltage goes higher because of the ...
0
votes
3answers
59 views
Can I put Li-ion batteries in series and discharge them at different voltages?
I need to run a pump (drawing 95mA at peak flowrate) at +14V and the rest of my circuit runs on +3.3V.
To save on battery costs, I was thinking of purchasing four 18650s at 3.6V 3500mAh per cell and ...
1
vote
1answer
32 views
Arduino battery power stay on for button - Not quite working
I have been trying to get a circuit to work that would power an Arduino from a set of 4 18650 batteries. It needs to turn on with a button press, then stay on for 30 seconds, then completely power ...
1
vote
2answers
52 views
Powering an onboard car GPS tracker
I made a car tracker (a GPS/LTE module connected to an arduino that communicate to my web server) to log gps positionning data. I’m planning to use this to track my new car in case it gets stolen.
My ...
3
votes
2answers
1k views
Using 5 V adapter to power 12 V cordless phone
I am trying to power a 12 V 8 W cordless phone using a 5 V 1 A wall adapter.
I am using a step up DC/DC boost converter MT3608 for boosting output from 5 V to 12 V.
Theoretically it works - when I ...
0
votes
1answer
71 views
Led on breadboard burned out why?
Please be kind as I am fairly new to electronics. Anyways, from what I read on multiple forums the rules are fairly straight forward, but I am puzzled as to why my led burnt out. So I connected the ...
0
votes
1answer
49 views
9V Battery Current Range
What is the range of currents that I can safely draw out of a 9V battery without damaging it?
I am planning to design an experiment and I don't want to draw too much of current out of a battery and ...
-1
votes
0answers
19 views
Battery power for pump, smart battery
I’m trying to wire up a breast pump for my wife to run off a battery.
The pump itself has an ac adapter that outputs 12v 2A, And I have a laptop battery (Hyperjuice) that says it’s rated for 14.5-18....
0
votes
1answer
37 views
not sure which battery to use (drone) [closed]
i want to build a drone and i have the motors but i need a strong battery, and i dont know much about it
i didnt understand why the motors didnt work, and then i saw a question of someone here who ...
1
vote
1answer
81 views
Are there 5V battery packs available without a boost converter? [closed]
Looking for a 5V portable power source without switching or conversion noise.
-1
votes
0answers
63 views
Samsung Powerbot Vaccum - bypass charging dock?
I have a Samsung powerbot VR9000 robot vaccum. It has 2 contacts on the bottom of the robot and docks with a 'charging station' when it is low battery. The charging dock does not charge it at all. It ...
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0answers
36 views
Use multiple batteries in series vs Using a boost converter
I have encountered a circuit that totally confuses me:
I have a simple LED flash light that came with my electric bicycle. The flash light is designed to work with a range of 24V-36V so it can be ...
0
votes
2answers
37 views
Can batteries in series be reverse charged if the circuit is open?
Suppose I have four AA batteries hooked up in series and I forgot about them and one of them eventually got completely empty due to self discharge. Also suppose that these batteries are not connected ...
0
votes
1answer
64 views
Arduino and 3W LED sharing the same power source, is it possible and how?
I've built a remote control for my 3W power LED with an Arduino UNO and I'm powering the Arduino with a USB cable and the LED with 4x AA NiMh batteries (1.2V). Is it possible to power both my Arduino ...
0
votes
6answers
202 views
led I can stick on a AA battery [duplicate]
I have a toy for my son, it's great but it flies round and round in the dark, I was thinking of sticking an LED on it like we used to do at school - back then LED's were rubbish but they had long ...
