>output 5V 2A What's a good power bank that let's

>>58368573
i would also like to know this, everything on amazon i've looked at looks cheap as fuck

>>58369860
They're inefficient as fuck is my problem. That and they struggle to put out more than 0.8A

>>58370239
that's pretty retarded, it's just 5v that's practically ideal for a 2cellx2cell series/parallel

>>58368573
QD 188. High quality, takes 8x 18650 and does up to 24 V output (yes you can charge your laptop).
Or the cheaper QD 186. Same thing, less cells and no 24V out.

I dunno, why not just buy a xiaomeme or anker or something if you want something good. probably cheaper than sourcing 3kmAh cells yourself.

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>>58368573

>>58370389
Because it isn't cheaper than sourcing 3400mAh cells for everyone?

My laptop has a 42wh battery and gets sosmething like 7 hours off of it.

This calculator told me that a single 18650 3000mah at 15v is 45wh. My laptop is able to run for 7 hours off of a single fucking battery?

If I had a portable charger with room for 3 18650s could I run the thing for 21 hours off of it?
28 actually counting for the built in 7

My head is going to fucking explode how does one tiny ass battery power a cpu ssd fhd display fans for that long

>>58370642
Your calculation is wrong. Laptops typically have 6 18650 cells in their battery.

>>58370742
The Dell website says "42wh 3 cell battery". I don't know much about basic electronics. Can you correct my calculation?

>>58370751
42/3 = 14

14/3.7 = 3.8Ah

Impossible for an 18650 cell, they peak at 3.4Ah last time I checked, or 12.6wh per cell.

Your laptop must be using Li-Po cells instead.

>>58370751
3000 mAh = 3 Ah

3 Ah * 4.2 V = 12.6 Wh

So your laptop has the equivalent of ~3.5 18650 cells.

mAh is retarded anyway I don't understand why it isn't all in Wh.

>>58370822
wh isn't calculated with peak voltage usually, is it? Lithium ion cells are usually 3.6, 3.7, or 3.8V depending on the manufacturer.

>>58370822
That makes much more sense. I'd like to purchase one of these power banks too.

It's still amazing just how power efficient my piece of shit $500 dell is.

>>58370844
Well to do it properly you'd need the voltage graph from full to empty, doing it that way was just to give an estimate to show how a 18650 compares to a laptop battery.

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>>58370889
Nah lithium ion cells are 3.7v, just checked.

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>>58370999
Nice trips, but voltage drops as a cells discharges. 3.7 V is their rated output.

>>58368573
I have a tomo, but I wouldn't recommend it. It discarges when it's turned off.

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>>58368573
> dat power display dongle

Neat.

>>58370999
jesus christ SIXTY FOUR AMP DRAW
is this for jump starting a fucking car?

>>58371824
Vaping, actually.

>>58370853
>It's still amazing just how power efficient my piece of shit $500 dell is.

Because it is a piece of shit.

Higher performance chips require more energy.

>>58371889
I think a SMT dual core chip on 14nm is fine for most tasks. Plus it has a 1080p IPS panel @ 13.3", user accessible SSD and 2 DIMMs. Decent keyboard, trackpad. Can't complain for $500.

>>58371870
i know what they're used for lol but what was the original intended purpose of such a cell

>>58372381
There was likely no clear purpose. High drain batteries are sought after by people buying one or two cells (as opposed to OEMs buying in the millions) due to their perceived safer chemistries and lower chances of assplosion than standard ones.

Use them in those ridiculous custom LED flashlights, electric bikes/skateboards/vehicles or whatever else you can think of.

Efest is also much more generous than other manufacturers about discharge capability claims. You're likely taking that thing right to the limit on 64 amp draw.

>>58368573
I hear wall outlets are pretty fucking good, OP

>>58372381
>>58372530
Forgot to add: Actually starting cars. I read somewhere that certain manufacturers had started replacing lead-acid batteries with li-ion, especially in cars with a fucking ridiculous amount of electronics that otherwise slowly rape lead-acids.

I think it was Porsche. Not too sure.

>>58370844
>>58370889
>>58370999
>>58371057

3.7V is the 'nominal' voltage of a lithium ion/polymer cell. The full charge voltage is 4.2V & the full discharge voltage depends upon how much you want to abuse the cell, but <3.0V is definitely danger territory.

Capacity is calculated using the nominal voltage.

>>58371824
>jesus christ SIXTY FOUR AMP DRAW

That's the burst rating (probably rated for 10 seconds) & even that is nothing compared to decent racing drone batteries