# How to Make a Solar-Powered DS Lite

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March 29, 2007 5:29:26 PM

After building its last invention, the solar-powered Wii, the gang at Toms Hardware Guide decided to go for something smaller: the Nintendo DS Lite. Here's how THG built a DS Lite that runs entirely off of solar energy.
March 29, 2007 6:26:39 PM

YES!

Finaly a gadget that makes my DS lite less portable while saving the earth!

Maybe I should just hook my DS to a transformer?

KUDOS!
KUDOS indeed

j/k nice mod
March 29, 2007 10:38:05 PM

So has anyone computed the real savings in terms of \$\$ of having a solar powered DS?

Alternately, does this really "save the earth"?

Let's see -- \$120 bucks (not counting labor) to make a DS lite solar powered. How much would it cost to charge one from a power outlet over it's lifetime?

Ok let's do some crappy math:
5.2V * 1 amp (why 1 amp, because I couldn't find out the actual load so I went extermely conservative) = 5.2 watts.

3 hours to charge for ~15 hours of game play (right off the webpage for the DS).

That's like: 15.6 watt/hours a day. (assumming 15 hours of gaming a day).

Now assume you game everyday for 5 years:

365 days * 15.6 watt/hours * 5 years = 28,470 watt/hours

Why 5 years, because I made it up...besides by then that poor DS would be wore out!

I pay ~15 cents per Kilo-watt hour in California. So the bottomline cost is:

\$4.27!!!!! 8O

Ok, I'm not an Electrical Engineer and I didn't compute charging losses and I may be totally full of crap, but why would you want a solar powered DS Lite again?
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March 29, 2007 11:14:04 PM

Quote:
So has anyone computed the real savings in terms of \$\$ of having a solar powered DS?

Alternately, does this really "save the earth"?

Let's see -- \$120 bucks (not counting labor) to make a DS lite solar powered. How much would it cost to charge one from a power outlet over it's lifetime?

Ok let's do some crappy math:
5.2V * 1 amp (why 1 amp, because I couldn't find out the actual load so I went extermely conservative) = 5.2 watts.

3 hours to charge for ~15 hours of game play (right off the webpage for the DS).

That's like: 15.6 watt/hours a day. (assumming 15 hours of gaming a day).

Now assume you game everyday for 5 years:

365 days * 15.6 watt/hours * 5 years = 28,470 watt/hours

Why 5 years, because I made it up...besides by then that poor DS would be wore out!

I pay ~15 cents per Kilo-watt hour in California. So the bottomline cost is:

\$4.27!!!!! 8O

Ok, I'm not an Electrical Engineer and I didn't compute charging losses and I may be totally full of crap, but why would you want a solar powered DS Lite again?

to be the only kid on the block with one??????
March 30, 2007 12:55:44 PM

The claim is the DS Lite runs 19 hours on the original 3.7V 1200mAh Lithium Ion battery.

This means that conservatively speaking at 15 cents per kilowatt hour, you'd have to recoup 800 KWHrs to break even. Where I live it happens to be 9.9 cents per KWHr.

At 800 KWHrs, with 19 hrs runtime, calculating some overhead, it seems it uses about 1/4 to 1/3 watt per hour. Based on this, 2400 - 3200 hours you'd have to play the device before you broke even.

Be sure not to break/crack the solar cells, or the DS Lite before then.

Cheers
March 30, 2007 1:34:12 PM

I'm not sure I agree with your math, John. In your case you seem to break even after about 130-180 days of continuous playing. That doesn't seem so bad.

I actually computed it would take about 100 YEARS to break even with continuous play.

Lets go through it again with your numbers:

3.7V times 1.2 amphr = 4.44 Watthours per day (assumes only gaming 19 hours a day -- your numbers)

At 9.9 cents per KiloWtHr = 0.04356 cents per day or \$0.0004356/day

To break even with a \$120 solar cell, you'd have to run:

120 / 0.0004356 = 275482 days or about 755 years!! 8O

Did you mean years rather than hours in your calculations?

So how long do you suppose that solar cell will last? Regardless, it makes NO sense to put a solar cell on a DS!
March 30, 2007 3:59:29 PM

What's this? Only gaming 19 hours a day gaming, there's 24 in a day, don't be wasting 5 hours on productive work or sleep!
March 30, 2007 4:17:19 PM

Quote:
What's this? Only gaming 19 hours a day gaming, there's 24 in a day, don't be wasting 5 hours on productive work or sleep!

The other 5 hours is the time required to stuff a couple of slices of pizza in your month, urinate, take a power nap, all while your DS is recharging.

I guess what you should do then is get a spare battery (more \$\$) that could be charging on the solar cell while your gaming. Then, I guess, you could figure out how to game 24/7!
March 30, 2007 4:43:33 PM

LOL.

What will you guys solar power next? my PC? you know you want to.

Good work.
March 30, 2007 5:02:45 PM

Thanks for the comments, guys. Good points on the cost analysis. The Soldius 1 isn't economically attractive. I was hoping the device would be more in the price range of \$40 to \$50, which still doesn't save you money in the long term because the DS Lite's draw for the battery recharge is low. Honestly, I have no idea why these small units cost som much considering the large panel for the Solar Wii was only about \$80 more and had much more power to offer. The hardware itself isn't all that complicated, the parts are cheap and the design is very basic.

However (and I probably should have spelled this out in the article) we fiddled with this mod for the sake of convenience. In other words, we wanted to alter the system so that you didn't necessarily have to find an outlet and recharge the DS if you're playing it for hours on end. Especially during travel, it can be hard to find an outlet to charge your cell or laptop or whatever. So we attached the solar panels to free up the DS Lite in that respect. For example, if you're on a 16 hour flight to China and had no place to charge your DS, theoretically you could open up the solar panels, set it on the tray table and let nature do the rest.

As for the sun glare factor, yes, it was a complete b*tch, which is why we put the battery back in. If the only time you could play the DS was in mostly sunny weather, you'd get a serious headache from squinting.
March 30, 2007 5:03:31 PM

Ahhh, you caught me, MisfitSELF.

You are right, since I said 800 KWHrs, I should have taken
800,000 / watts used which basically means take my numbers and multiply by a thousand.

That basically means it would take a thousand years or so of using it 2400-3200 hours per year all factors bearing equal for the entire duration. Factoring in deflation of investment, you could basically say you'd never break even, assuming the solar cells and device continued to work indefinitely.

John
March 30, 2007 5:05:10 PM

Quote:
Thanks for the comments, guys. Good points on the cost analysis. The Soldius 1 isn't economically attractive. I was hoping the device would be more in the price range of \$40 to \$50, which still doesn't save you money in the long term because the DS Lite's draw for the battery recharge is low. Honestly, I have no idea why these small units cost som much considering the large panel for the Solar Wii was only about \$80 more and had much more power to offer. The hardware itself isn't all that complicated, the parts are cheap and the design is very basic.

However (and I probably should have spelled this out in the article) we fiddled with this mod for the sake of convenience. In other words, we wanted to alter the system so that you didn't necessarily have to find an outlet and recharge the DS if you're playing it for hours on end. Especially during travel, it can be hard to find an outlet to charge your cell or laptop or whatever. So we attached the solar panels to free up the DS Lite in that respect. For example, if you're on a 16 hour flight to China and had no place to charge your DS, theoretically you could open up the solar panels, set it on the tray table and let nature do the rest.

As for the sun glare factor, yes, it was a complete b*tch, which is why we put the battery back in. If the only time you could play the DS was in mostly sunny weather, you'd get a serious headache from squinting.

haha yea
There was major squintage in the video.
Anyway its innovative... only kid on my block with a SP DS lite!
March 30, 2007 5:16:10 PM

Hi Rob,

Yes, I think probably a more viable design would be one which used the back of the lid, with a hard clear cover. If it was designed to trickle charge using less solar cells, at least you could let the unit rest a while in the open, and it would recover some power.

I'd guess with a circuit to increase charging voltage, you could take a single \$10-15 cell, and trickle charge the thing to both boost battery power, and recharge during non-use. This would mean if it's been sitting a while, it should play without having been plugged in. Probably with the right charging circuit, you could do the whole thing for \$25 + time + planning.

This of course assumes it doesn't grow legs while charging.

This one is 4V which might not even need much of a voltage regulating circuit, although, I don't know the charging voltage for a DS Lite.
http://store.sundancesolarcorp.com/misopa4v10.html

For example, my guess is that could be rigged up to charge at about 70-100mAh or so at the proper voltage. Which would basically give you 1 hr of play for 3 hrs charging, and would extend play time even with the lid open, at least if there was some light around.

John
March 30, 2007 6:07:33 PM

Rob,

I thought about the convenience factor too. Perhaps, (if it wasn't for the fact that they have a custom battery), it'll be easier to bring an extra battery along. It'll be cool if the DS ran off a 2 or 3 AA's or AAA's. Then you could get a battery charger set from Costco (or Walmart) and just carry extra batteries along.

This would cost you about \$20 and you don't have to squint! But alas, custom battery....

Newegg has a battery for \$10 for the DS Lite, but it's advertised to only provide an extra 3 hours of gaming. So that doesn't exactly solve our "16 hour flight to Hong Kong" problem.

Maybe you could rig an old laptop battery to the DS (use the laptop itself as the battery charger)? My 4 year old Compaq X1010US laptop has a battery that is rated:

14.8V, 4.4 amp hours, 64 watt hours. Assumming you could down convert the voltage to an acceptable level without loses then you could power that DS for about 16 hours. (based on 64 watt hours / 4 watts estimated usage of the DS Lite).

This could be done for about the same cost as the solar cell and would work in low or even no light. No you'd just have to haul around a laptop battery around and a laptop to charge it....
March 30, 2007 6:22:11 PM

The 4.4 watts was total battery usage which was estimated to last 19 hrs on stock 3.7V 1200 mAh batteries.
April 2, 2007 7:23:54 PM

They did it because they could! I think it is brilliant. and I bet you can sell it for 2 to 4 times its cost on Ebay!

I have a serious question, but please keep in mind that although I am curious, I am also completely ignorant of the technology. Was the solar equipment the smallest you can buy on the market, or just the smallest you can buy as a regular consumer?

Just curious why the manufacturers are not using solar devices should the latter be the case.
April 2, 2007 7:31:37 PM

Quote:
I have a serious question, but please keep in mind that although I am curious, I am also completely ignorant of the technology. Was the solar equipment the smallest you can buy on the market, or just the smallest you can buy as a regular consumer?

Well, as I stated in the article, we didn't order a solar panel this time for the DS mod -- we just grabbed a Soldius 1 charger that we already had sitting on the shelf in our lab. But as we've discovered from reader feedback, there are smaller and much cheaper alternatives on the market. And actually, there are quite a few places to buy these things online. Even some big retailers carry the technology now.

Quote:
They did it because they could! I think it is brilliant. and I bet you can sell it for 2 to 4 times its cost on Ebay!

Oh snap, that's a good idea...how much do you think we can get for it? Maybe we should start the bidding now on the Forumz.
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