nifty project : trying 2 power a laptop directly from PVCs

[bluefrog888]

hey all

I'm an avid hiker/camper and often i find myself taking a break with my toshiba 5205-s705 media center laptop only to find myself in the middle of nowhere without any games tv music movies and worst of all no GPS because the darned thing lasts only 2 hours tops!

   i'm trying to put some solar cells, taped right on the back of my screen and wired together to feed DC power directly into the notebook.  that way i could possibly just put the notebook into a transparent backpack compartment and have a freshly charged notebook when i set up camp, or better yet, sustain the notebook on solar power.

   Because i already have enough to carry with my camping gear and food on my shoulders the posibility of having a     solar panel>inverter>adapter>notebook system is too clumsy.

    my notebook normally has an input of 15v @ 5A and there's a surface aria of ~11.5"x11"

oh and I'd like to keep this project under $50

   I have a basic knowledge of electronics so I'd like some second opinions before i fry my notebook so here's my Questions

should I wire the cells in parallel or in series?

what kind of resistors or any other protective electronics should i put in?

where can I buy some raw PV cells that are efficient and cheap? (radio shack is ripping 5x3 cells for 7.50!)

what else should i know before i start?

any help would be greatly appreciated

thanx = )

[JeroenH]

You say you have an area of 11,5" x 11" available. That's about 0,082 sq.meter (sorry I'm European). At an insolation of about 800 Watts/sq.meter and a PV panel efficiency of 14 % you would be able to get about 10 Watts fram a PV panel of that size. Of course, the sun has to shine and the panel has to be perpendicular to the sun.

10 Watts would probably not be enough to run your notebook PC directly but should be able to charge your battery. Problem is, your computer might not like the fluctuating voltage the PV panel feeds it.

I'd say you would at least need some kind of battery to provide a stable power source, and then maybe a 12V-->15V converter for your computer. By then it would probably get too heavy to carry comfortably, and you'd still only have 10 Watts. If your computer uses 40 Watts (not uncommon for modern notebook PCs) you'd need to have your PV panel in the sun all day to get your full 2hr runtime at night. I'd say the 15V/5A indication on your computer is not the actual power consumption but it's te maximum consumption.