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josephjah
Paper Tape
Posts: 3
Registered: ‎09-04-2008
Location: M'Boro
Views: 1,004
Message 1 of 6

T60p Solar Modification Ideas

Hey everyone, I figure this is the most appropriate place to post this question but basically I have decided to outfit the lid of my T60p with some solar cells to augment the batteries while operating on the go, currently the proposed setup would be:

 

Given, T60p lid size = ~12" x 10"

 

16 X (.5v @ 1 amp) [4.5" x  1.5"] Solar cells -- Which translates to about a watt for every 12% of the surface I cover with these things (nominally).

 

Given my battery is 10.8v @  7.8 Ah and my battery typically lasts 4.3 hours => (7.8Ah/4.3h)*10.8v = 19.59w of power consumption on average when running on the battery and since I can mount enough solar cells to get roughly 8w max => 8w/19.59w = 40.8% of the power consumption would be matched by the cells.

 

So after doing some seemingly simple calculations I expect to reach a maximum of about 40% battery life increase (assuming the thing is exposed to full and direct sunlight... but it NEVER would be)... so I'm thinking maybe 15% in my working conditions. (But I'm mainly doing this for its regenerative purposes since the thing is often away from an adapter for over 2 days)

 

But basically... My question is this: Assuming I have the cells mounted, connected up, and protected, what would be the best method to get the extra juice to the battery?

 

I don't want to have any clumsy wires hanging around and I'm not sure but... could I maybe tap into something through this little panel-looking thing on the lid?

 

http://i38.tinypic.com/2hyifkm.png

 

Just for kicks here is an old mspaint mockup of what it was going to look like (using different panels), and of course the laptop in the pic is a widescreen and mine is not:

 

http://i38.tinypic.com/5v2ka8.png

 

The grey lines would be tin-foil "wires" and would be isolated of course.

 

Any help/ideas would be greatly appreciated!

 

- Joe

 

wjli2
Bit Torrent
Posts: 3,212
Registered: ‎02-16-2008
Location: Australia
Views: 984
Message 2 of 6

Re: T60p Solar Modification Ideas

Okay firstly, if you are going to place your solar cell laptop under the sun, which i think is a bad idea since laptop under the sun is not a terribly good mix. Most of the solar cells you buy from a store is dye based, and the conversion efficiency is only around 8% max, while 92 % of the sun's solar energy is going to remain as heat energy. Considering that thinkpads are black, it is going to soak up all that heat radiation like a dry sponge in water. Plastic in sun is not a good idea, i think you should get mount the solar cells on an external panel and leave the laptop where it doesn't get heated up so easily.

 

In addition, for most of the older solar cell technology, having 60% of brightness is not going to generate 60% of full current, it is not a linear relationship.

 

I think Lenovo is planning to release a solar kit for X300, i am not sure whether it has occured or not. 

 

But all in all i think you need to think through bit more carefully with your solar panel on screen idea. 

 

 

Centex
Token Ring
Posts: 164
Registered: ‎01-07-2008
Location: Central Texas
Views: 958
Message 3 of 6

Re: T60p Solar Modification Ideas

It's been my experience that the LCD screens on my two Thinkpads are very difficult to read outdoors in bright sunlight.

 

They need to be put in the shade, by getting inside a car or holding an umbrella over them or getting under a shade tree, or some such thing.

 

Wouldn't it be better just to purchase a spare / second battery?

 

Centex

 

Retired Moderator
Retired Moderator
Posts: 1,184
Registered: ‎11-20-2007
Location: Iowa, USA
Views: 940
Message 4 of 6

Re: T60p Solar Modification Ideas

Then why not make your shade out of a solar panel.

Then it would shield the sun from washing out the screen and keep the sun from heating things up while being big enough to produce enough power to run your Thinkpad.

______________________________________________________
T60 2623-D7U, 3 GB Ram. Dual boot XP and Linux Mint.
T400 2765-T7U Windows 7

Registered Linux User #160145

FYI: I am not employed by Lenovo
wjli2
Bit Torrent
Posts: 3,212
Registered: ‎02-16-2008
Location: Australia
Views: 923
Message 5 of 6

Re: T60p Solar Modification Ideas

carbon_unit that is a way better idea than sticking solar panels on your laptop.
Community SeniorMod
Community SeniorMod
Posts: 1,952
Registered: ‎12-02-2007
Location: AU
Views: 921
Message 6 of 6

Re: T60p Solar Modification Ideas


josephjah wrote:

 

Given my battery is 10.8v @  7.8 Ah and my battery typically lasts 4.3 hours => (7.8Ah/4.3h)*10.8v = 19.59w of power consumption on average when running on the battery and since I can mount enough solar cells to get roughly 8w max => 8w/19.59w = 40.8% of the power consumption would be matched by the cells.

 


Quite apart from the parctial aspects of mounting and connecting up your photo-voltaic array, you need to revisit your electrical calculations as you cannot simply take energy out of the solar array in the way you seem to be assuming.

 

In practical terms you will need a significantly higher voltage that the nominal battery terminal voltage (figure at least 25%) to be able to make up for the losses associated with getting the quite variable energy output from the solar array into the ThinkPad power system in a useable way.

 

Off hand, I think you will find that in practice its hardly worth the effort unless you have plenty of time to let the ThinkPad "recharge" from the solar array on the "lid" between sessions of use.

 

Cheers,

 

Bill  

------------------------------
I don't work for Lenovo

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