Questions tagged [capacity]
The capacity tag has no usage guidance.
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0answers
12 views
deriving an equation for wireless network capacity
I'm trying to derive an equation for wireless network capacity given topological constraints of the nodes and certain obstacles... but before I get that far, I want to understand the most simple case. ...
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1answer
47 views
Choice of wire diameter for doll's house?
I'm constructing a 1:12 scale doll's house and I'd like to use enamelled wire run within the walls for lighting. Each room would have its own circuit controlled through a switch and then to a common ...
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1answer
231 views
Calculate battery state of charge percentage
What is the correct formula to calculate battery state of charge percentage based on the battery type (12v, 24v, 48v and so on) and the current battery voltage.
For example if I have a 12v battery ...
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4answers
59 views
Which capacity measurement is the correct way to measure?
So I've seen batteries showing their capacity in mAh and I've seen others showing in Wh. Phone batteries are always measured in mAh, while for some reason BatteryInfoViewer on my computer only shows ...
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1answer
45 views
Why or when does battery capacity matter in a series circuit?
I have 3 sets of doubled 18650 cells from a laptop battery, and I gather that it can be dangerous to use cells of different capacities in series. This question is more about the theory than practice.
...
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2answers
60 views
Will a standard 9V alkaline battery (300mAh- 400mAH) be able to supply 2.5A for 5-10 second at a time? [duplicate]
For example, I have a motor that needs a surge of 2.5A for a short amount of time from a 6V power supply.
Will any 6V battery able to supply that current? Even if let's say it has only a 500mAH. How ...
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1answer
24 views
how to understand the capacity in binary symetric channel (BSC)
According to the wiki about the BSC (binary symetric channel),
given the bit flip rate p,
the capacity is derived as :
H(p) = -p*log2(p) – (1-p)log2(1-p)
C = 1 - H(p).
the error probability p ...
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1answer
55 views
Battery Pack Life Rating
I am working off of a schematic where I was given a battery pack with the following specifications. The battery being used is a panasonic NCR18650 lithium ion cell.
https://engineering.tamu.edu/media/...
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1answer
252 views
whats better? 20,000 mAh 5V Battery or 9Ah 18v battery to use as portable power charger?
So I bought battery brick from Amazon.ca it was a 20,000 mAh, it's a 5v battery pack. I also just bought a Milwaukee 9 Ah 18v battery for my tools and beside it I saw an adapter that let me click onto ...
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2answers
80 views
How Can I Find “temperature coefficient” of a Battery?
I am studying mathematical modeling of a battery in simulink and for this it is necessary to determine some parameters. I'm stuck in the part where I need to determine an alpha parameter, which would ...
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3answers
4k views
Running a desk fan off a car battery: How long will it last? [duplicate]
I'm going on a road trip and will be sleeping in the bed of the truck at night.
I want to be able to have a fan running during this time. I have a couple old car batteries sitting around, and I was ...
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0answers
68 views
How to find the voltage Capacity of a dead Battery?
I have a spare battery without any stickers or labels on it. I checked the terminal voltage and it was around 3.5V. I would like to know what the Voltage capacity of that battery will be (i.e) whether ...
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0answers
45 views
Optimal Capacity of Wireless Relaying
"Optimal approach to relaying occurs when transmission is recieved simultaneously at the destination and relay." Is this still valid in the light of recent research? Are there trade-offs involved?
...
0
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1answer
252 views
Stepper Motors Calculations
I am currently working on a project for PV tracking systems. I have two stepper motors, one for each axis to track the position of the sun and the power generated would need to primarily recharge the ...
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1answer
194 views
Designing a battery capacity monitoring system for AGM lead acid battery
I would like to design a battery capacity system for my AGM lead acid battery (12v, 40Ah). My idea is that I have values of the battery voltage and its corresponding capacity, which I will use to plot ...
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3answers
2k views
Is 18650 battery capacity from 3V or 0V?
To calculate the battery capacity in mAh of an 18650 battery I understand you can use something like an iMax B6 in discharge mode on a fully charged (4.2V) battery to get the mAh it provides. The iMax ...
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1answer
82 views
Can I connect different capacity Lion cells with protection circuit in parallel?
I have 13 no. 18650 batteries each is of different capacity, i want to connect those in parallel so wondering directly connecting them in parallel would be obviously bad idea so i was thinking that if ...
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1answer
63 views
Connecting diffrent lipo in series to achive high voltage
Im not so familier with lipo and liion but know there dangers
For my recent project i got an audio amplifier with works good on voltage of 14-18v so i need this range of voltage
My amplifier is ...
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3answers
526 views
Battery Nominal Capacity
I was wanting to buy a 12v battery that could supply 8A for around an hour. I thought I knew what I was doing and so ordered the following 12v 10Ah Deep Cycle battery.
Yuasa REC10-12 BATTERY Deep ...
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2answers
780 views
Wiper motor availability in 12v and 30 amps? [closed]
Is there any availability of 30 amps in 12v wiper motor and what is the maximum power of a wiper motor availability. I want to utilise the high watt wiper motor for different application.
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2answers
65 views
Determining Faulty Lithium Batteries in Battery Pack
I am having some difficulties with a 72V 200aH LiFePo4 battery pack that I am using in conjunction with an EMUS BMS. The BMS indicated some of the batteries were not charging properly, I corresponded ...
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1answer
339 views
Boost Converter: Low voltage high current VS. High Voltage, low current?
I'm in the process of assembling a 1000w total LED light bar, which consists of 10x100w chips, which at full power, consume 3A at around 35V. For this, I'm using 3 dc-dc boost converters, each which ...
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1answer
69 views
Any side effects when substituting bigger capacity battery in place of smaller capacity?
I have a car key fob whose batteries recently died. The coin slot says it accepts two cr2025 coin cell batteries.
But I was thinking, since a majority of coin cell batteries run at 3v, I should be ...
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1answer
9k views
Duracell PowerCheck - How Does It Work?
I've been using these batteries for a long time and I've never seen such a feature.
There's a band on its outer wrapping having two ends: The white circle on the left side and the another one on the ...
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2answers
235 views
cache memory capacity and words in cache memory
Each block of the set associative cache memory has capacity of 4 words of 16-bits, one section has 2 blocks. Whole cache memory has 4096 words.
I do not understand the differences between these bold ...
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7answers
1k views
Excess capacity in the power grid
My question concerns capacity in the power grid. I am an attorney trying to understand whether excess capacity runs in a power grid to avoid brown outs and how long can the excess capacity exist ...
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1answer
195 views
What kinds of batteries have the highest energy density?
My question is, what kinds of batteries have the highest amount of watt hours per cm3? I know, comparatively, that for example li-ion batteries in phones generally have a higher capacity than, say, ...
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3answers
375 views
Can the capacity of a battery be determined from Volts, Amperes, and output of Joules for xyz amount of time?
I'm trying to purchase a portable car battery charger (Noco Genius Boost) and I can't tell if it's possible to calculate the capacity in Ampere-hours or Watt-hours. The reason why I ask is because ...
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1answer
53 views
Sizing a battery according to an existing solar panel (and not the opposite!)
I have one 60-cell 260Wc ~30V ~8.5A panel left over after a solar installation.
I did record consistent and factual 1400Wh per day and per panel in winter.
I want to use the energy of this extra ...
4
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3answers
380 views
High Capacity Phone Batteries - are they for real or a scam?
I recently bought a new, allegedly high capacity battery for my Samsung Galaxy S5. It was being sold as a 3800mAh battery whereas original is a 2800mAh battery.
On inspection I read the following from ...
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1answer
364 views
Conventional way to measure Li-Ion cell capacity?
I have an 18650 Li-Ion cell taken from an old powerbank, and was interested to find its capacity so I built a capacity tester. This consists of a meter (displaying volts, amps, and mAh), two 6V 5W ...
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2answers
2k views
How to calculate amp hours when voltage and amperage changes [closed]
I have a Lithium battery pack. All I know about this battery is that its no-load voltage is exactly 20.0v when charged. I then connect a load to this battery; I have no direct information about the ...
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0answers
568 views
At which current density (mA/g) we should get the theoretical specific capacity of an active material?
If we take graphite in LIB as an example. When testing a battery, at which current density (mA/g) we should expect it to reach its theoretical capacity of 372mAh/g? What would be the capacity of ...
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2answers
138 views
Lithium ion battery impact of cycles on discharge rate
Basically all I've been able to read and find out until now is that the capacity of lithium ion batteries goes down with cycles. I'm currently programming an arduino to accurately estimate the State ...
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1answer
2k views
Does an inverter only draw power from a battery as-needed?
In other words, does a 1000-watt inverter, draw the same as a 500-watt inverter if they are charging only a laptop? The laptop will draw the same amount and the inverter capacity is really just that, ...
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1answer
79 views
Microcontroller Interface IC
I am planning to communicate from my dsPIC33FJ64GS608 Microcontroller with a HEF4894B IC.
Because of the Microcontroller is running at 3.3V I want to drive the IC also with 3.3V.
According to the data ...
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2answers
213 views
LiPo battery capacity valid at what discharge current?
I would like to know for which discharge current the given capacity of a LiPo battery is valid. Let's say a battery is sold by the manufacturer as 400mAh capacity. Is there a standard discharge ...
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1answer
108 views
what could be the resulting mah if four 150 mah ,four 800mah and four 1000mah rechargeable cells all of the 12 cells in series to each other?
i wanted to know that what could be the resulting Mah if i connect four 150mah ,four 800 mah and four 1000 mah rechargeable cells all of the 12 cells in series to each other?all 1.2v
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2answers
712 views
Relation between battery cell capacity & internal resistance
I'm trying to design a large battery pack, that should provide a given amount of power, with a reasonable amount of heat dissipations. To do so, I have three degrees of freedom:
indidividual cell ...
0
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1answer
83 views
How to calculate correct value of capacitor C2? [closed]
I have the following connection, what should be the correct capacity of C2, for the case when the device is turned on, so it will load untill my MC will be not ready? Thanks
0
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1answer
747 views
Does manufacturing different sized hard drives cost the same amount? [closed]
Is there a major difference in the cost of manufacturing, say for example, a 1 TB hard drive as compared to a 250 GB hard drive? Is it the same when hard drives get even as big as 8 TB?
If no, then ...
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2answers
323 views
Alkaline AA discharge curve at just a few mA (to replace a CR2032)?
I bought a pack of tealights each powered by a single CR2032 (flickering LED; builtin timer turns it on every evening for 5 h). My wife loves them, but after just a fortnight each tealight's CR2032 ...
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2answers
724 views
How is a battery's capacity (mAh) compared to a fuel cell capacity?
Batteries (Li-ion, Li-po, Ni-mh etc.) are all rated in mAh, which gives their capacity (C). But what about hydrogen fuel cells? How can we rate their capacity? I have done some research, but fuel ...
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4answers
6k views
What is the valid capacity ranges of Lithium Ion 18650 batteries?
I'm seeing wildly varying capacities that are seemingly fake on 18650 cells, such as these "9,800 mAh" ones on eBay, but are ~$1 / cell.
However, 'genuine' cells from Panasonic and similar name ...
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5answers
10k views
Testing Chinese CR2032 Li-ion Battery Capacity
I recently bought a lot of cheap CR2032 batteries from aliexpress. Since there is no manufacturer stated on the package or the batteries, I would like to know if these batteries really have 220 mAh or ...
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1answer
621 views
What does “capacity achieving code” mean?
I am an electrical engineer passed several courses in information theory and coding theory, however as I think now, I see that I have not understand the basic ideas in these concepts till now.
We ...
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2answers
243 views
Get Li-Ion battery capacity from discharge time (constant load)
I would like to ask if there is some easy enough way to calculate Li-Ion battery capacity if I measure the discharge time with constant load (not constant current!).
I have made a "discharger" using ...
0
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4answers
298 views
AA Battery capacity
The load is 227mA at 25ms (this is pulled 20times in a minute )and 0.001A for the rest of the time from 4 AA batteries. If this test is running for 20 days, I need to calculate the voltage left on the ...
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3answers
243 views
Battery Capacity
I'm new here but I have read some interesting posts on this website so you all might be able to help me.
I need to calculate the battery capacity I need to run the device.
My load is 300mA at 20ms and ...
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3answers
3k views
Determine the amp hour rating of a home made battery pack
I'm thinking of making my own electric bicycle, and I need help determining what the amp hour rating of my battery pack would be. I'm going for 36v and 8 or 9 amp hours.
So, with 10 batteries in ...
