Just curious...

[Guest]

How many AA batteries would it take to power a PC for one minute

[SageOfSpice]

Idle? About 20.

Load? About 100.

 

Alkaline batteries tend to drop in voltage as they drain though, so you'd probably want quite a few more.

[SLAYR]

56 minutes ago, wrathoftheturkey said:

Quick Google: 1 AA battery = 3.75 Wh

Load temp: 400 W

400/3.75 = 106 batteries for an hour

106/60 = 1.76 batteries per minute

It isn't that simple, there is also extra power going to be used for that DC power to be converted to AC for the PSU to use, or the step down the DC voltages to something the computer can use.

[incarnate]

1 hour ago, wrathoftheturkey said:

K then, maybe two. Just napkin math, jeez

Each battery is 1.5v so it would take much, much more than that. Seeing as how the input voltage into the psu is ~110v, so a minimum of 74 would be needed, in series.

 

This is also ignoring the fact that the input power is supposed to be ac not dc

[incarnate]

58 minutes ago, wrathoftheturkey said:

Theoretically though, if you were to drain the batteries completely and then convert all that energy to AC, and to the right voltage with zero power loss, I mean, you wouldn't need as many

that's not how batteries work.

[Canada EH]

I hate to nit-pick, but forget everything you typed.

 

You would need to figure figure out the RMS for 120Vac, then build for that dc voltage. I doubt its an inductive load for the laptop adaptors.

Its better to go with either LiPo, LiFePO4, or Lithium as their voltages are higher. Even used laptop batteries would work, taken apart and just use the cells. So Lipo is 4.15V charged, RMS is probably 80V, so 20 cans each has 2.5Ah and can spit out 5A. Or what about using 9V square battery, primary is 1Ah, who knows what it can discharge.

[thewipyk]

Let me help this with phisics. For operating a circuit board, you need 2 things: Ampere and Volt. Should you connect the batteries in paralel, the A stack, otherwise the V stacks. To power a CPU, you need 12V, which means 8 batteries. 

Let's say the CPU is 50W. 50/3.4 is roughly 15. So 2 8-lines into paralel will power the CPU. 
This works for the MoBo, GPU and other stuff. (let me spare the math)  I'd say you need roughly 250 batteries, so your system can actually run for a minute with enough juice.

[Canada EH]

Yes series connection is added voltage, and parallel connection is added Ah.

Ah is how long the device can run for. Laptops would need very little discharge, thats why they use cheap batteries, cheap meaning they got low discharge rate. Where as a high discharge battery is 2x or more the price, along with the Ah of course.

 

Only way to accurately figure it out is to run the PC on a watt meter.

Random search came up with this

Quote

Laptop computers may peak at a maximum draw of only 60 watts, whereas common desktops may peak around 175 watts.

 

 

Oh wait, brain fart here. Laptops run on batteries. I meant to say desktop. Laptops you can just make your own battery pack and plug it right in, its not wise to do so because the original battery pack has a BMS for safety reasons, for the charge and discharge rates. But yeah so you'd need 200W or more to run a desktop PC. 80V and 2Ah = 160Wh, so perhaps you'd need 4Ah-5Ah.