electricity question

[prophetmuhammad]

if i get myself a 40-watt solar panel, how long can i power a laptop for? say the laptop power supply is rated at 20 volts, 3.5 amps, 65 watts, plugged into a 220 volt outlet.

and is there a formula to calculate this?

thanks

 

[busydude]

Prophet Muhammad asking questions about electricity?

Mind.. blown!

 

[dighn]

question does not compute. how long you can power the laptop for is a measure of energy, not power. without a battery to charge up first, a 40-watt solar panel cannot power a 65-watt device at all (though it *might* work as the 65-watt figure is the maximum draw - but I wouldn't run it that way even if it did work somehow)

actually wait a second, this looks like a troll question.

 

[prophetmuhammad]

Mind.. blown!

oh allah so many vulgar jokes can come out of this.

 

[prophetmuhammad]

question does not compute. how long you can power the laptop for is a measure of energy, not power. without a battery to charge up first, a 40-watt solar panel cannot power a 65-watt device at all.

alrighty, so how big of a capacitor would i need to charge a laptop? it takes about 2 hours to charge my asus. and how long would it take to charge the capacitor fully?

total n00bquestionpwndlulz

 

[dighn]

alrighty, so how big of a capacitor would i need to charge a laptop? it takes about 2 hours to charge my asus. and how long would it take to charge the capacitor fully?

total n00bquestionpwndlulz

for just charging the laptop, a lower input power might be fine. but you can't just run it like that. what does the solar panel output (voltage etc. you got an inverter?)?

 

[Red Squirrel]

You can't just hook it up directly, you need a charge controller and a battery to store energy. The panel will produce various voltage/wattage based on the sun so the charge controller regulates this and charges the battery properly. Basically what you'd do is run the setup without the laptop for say, 2 hours, then run the laptop and get maybe 1 hour out of it.

Think of it as filling a water container at a varying rate, while also taking out from it at a steady rate. You need to be able to fill it faster than what you're taking from it. If you can't then you have to stop taking for a bit to let it fill.

 

[prophetmuhammad]

for just charging the laptop, a lower input power might be fine. but you can't just run it like that. what does the solar panel output (voltage etc. you got an inverter?)?

You can't just hook it up directly, you need a charge controller and a battery to store energy. The panel will produce various voltage/wattage based on the sun so the charge controller regulates this and charges the battery properly. Basically what you'd do is run the setup without the laptop for say, 2 hours, then run the laptop and get maybe 1 hour out of it.

Think of it as filling a water container at a varying rate, while also taking out from it at a steady rate. You need to be able to fill it faster than what you're taking from it. If you can't then you have to stop taking for a bit to let it fill.

i'm aware of this

so the solar panel isn't what's important, but the charge controller and the battery, eh?

 

[Red Squirrel]

i'm aware of this

so the solar panel isn't what's important, but the charge controller and the battery, eh?

Yeah pretty much. The battery is what will supply you a constant source of DC voltage. The solar panel, wind turbine, or whatever you decide to use will generate dirty/unstable electricity which needs to be regulated by the charge controller to charge the battery.

At least that's from my understanding. I've been doing lot of reading up on this stuff but have not actually implemented anything yet.

 

[prophetmuhammad]

http://www.ebay.com/itm/10A-Solar-P...602?pt=LH_DefaultDomain_0&hash=item23112e9fd2

http://www.ebay.com/itm/10-Multi-So...821?pt=LH_DefaultDomain_0&hash=item3cbe8529ed

and some used car batteries

gud?

 

[prophetmuhammad]

Yeah pretty much. The battery is what will supply you a constant source of DC voltage. The solar panel, wind turbine, or whatever you decide to use will generate dirty/unstable electricity which needs to be regulated by the charge controller to charge the battery.

At least that's from my understanding. I've been doing lot of reading up on this stuff but have not actually implemented anything yet.

alright, so basically an energy source and a capacitor. gotcha

 

[Red Squirrel]

http://www.ebay.com/itm/10A-Solar-P...602?pt=LH_DefaultDomain_0&hash=item23112e9fd2

http://www.ebay.com/itm/10-Multi-So...821?pt=LH_DefaultDomain_0&hash=item3cbe8529ed

and some used car batteries

gud?

That should do it. Not sure what they mean by 12V 24V, either you can toggle between on the device, or pick between when buying. 10 amps at 24 volts will give you 240 watts.

Only thing I'm not sure about is the output. You'd want to get an inverter that matches.

So basically:

Solar panel => Charge Controller + battery => Inverter => 120v device

If the laptop takes 12 volts, you can skip the inverter part and plug straight in, if it's 12v output.

 

[ussfletcher]

alright, so basically an energy source and a capacitor. gotcha

Not sure if srs?

 

[prophetmuhammad]

cool. an inverter, eh?

this potential project is giving me a hardon.

 

[Number1]

Are you going to blow anything up?

 

[Zebo]

Well 40 watts is less than 65 watts and there is some loss due to heat during conversions. However your laptop probably never uses 65W. You don't need to do any conversions since power is given for both. I'd get at least an 80W panel though.

P=IV

 

[prophetmuhammad]

Are you going to blow anything up?

harhar.

i'm muslim and offended.

 

[ThatsABigOne]

If you are offended then why visit this site? This site is full of pric... I mean good guys.

 

[Red Squirrel]

Are you going to blow anything up?

lol haha

Wait, maybe he is. Scrap what I said, it wont work. You need a solar laptop, a regular one wont work.

 

[prophetmuhammad]

If you are offended then why visit this site? This site is full of pric... I mean good guys.

i deal with borderline racist comments quite often in real life, and it's not like I can avoid real life, so why bother avoiding virtual places?

 

[JEDI]

how much is this solar panel/charge controller setup?

might be useful when the 2012 apocalyspse comes

 

[olds]

OP, Welcome back, free porn?

 

[skyking]

Conversions from AC to DC cost a minimum of 10% at a small scale.
laptops = ~19 volts DC.
many solar panels are around 19 volts. I can find them from 15 to 20 volts.
Set up a 20 volt charge controller, you can build your own.
Charge a 6 and 12 batt in series.
12v batt has ~13.2 volts. 6 has ~6.6
convert nothing. build a direct cord.
EDIT:
Holy crap, this is a breakthrough. I can build a 19v and a 12v system in my custom RV, since just about all the smallish LCD TV's are ~19 volts as well. switch the panels to different controller as needed.

 

[SooperDave]

harhar.

i'm muslim and offended.

Good job painting a target on yourself. The usual suspects will be along shortly to start taking pot shots. Befriend a mod. It is your only hope