Solar DS "Light" Redone and Improved

Step 17: Option 2

In my previous instructable, many people were saying they wanted to build a base that would stay in the sun all day collecting power and transfer it to the DS overnight. So I came up with a schematic for a device like that.

This switch changes between charging the battery from the solar cells and transferring the charge to the DS.

Comments

[ZeroXL91]

Wait, so like that guy said, is it possible to have a battery that can charge with solar and DC power?

[winter-chaos]

I need to reduce the voltage down to 4.5 or 4.6 volts for the DSi, any suggestions how I can do that....

[dark sponge]

It would probably be fine with 5 volts but I woouldn't risk it. You could look into circuits using an adjustable voltage regulator. It's similar to a 5 volt one but you use a set combination of resistors to set a specific voltage.

[winter-chaos]

thanks that helps alot, ^^.

[pyro2992]

On the switch isnt there normally only 3 prongs? two positive one negative, could you please calrify how you would set this up and on what kind of switch

[dark sponge]

This one does have three prongs, and none of them are positive or negative. When the switch is in one position the middle and one of the prongs are connected, and when it is in the other position the middle and the other prong are connected.

[InfraBlue]

Will a 150mAh 9v battery be able to charge my 1200mAh ds battery?

[dark sponge]

 Here's some quick math:

150 mAh = .15Ah
.15 Ah @ 9 v = (.15 x 9) = 1.35 watt hours

1200mAh = 1.2 Ah
1.2 Ah @ 3.7 v = (1.2 x 3.7) = 4.44 watt hours

So the answer is no. I'm guessing you are going to use a 5v regulator and putting the 5v through the charging port. Assuming you use a 7805 voltage regulator for 5 volts, which gets about 60% efficiency on average:

1.35 x .60 = about .8 watt hours

If this is correct, it would take the power of about 6 batteries to fully charge it, assuming the charging circuit in the DS is extremely efficient (and it probably isn't) and barely any power is lost through the battery itself. My recommendation: If you are using the 7805 idea, wire six (or slightly more) AA rechargeable batteries together to make a replacement 9v. It will have between 2000 and 2500 mAh (depending on the batteries you use), and should be able to fully charge the battery.

[InfraBlue]

Thanks
I have found a more efficient way to charge the ds battery.
Diagram
Hope this helps

[dark sponge]

The only reason that was is more efficient is because the battery was made lower voltage in order to remove the 5 volt regulator. While this is slightly more efficient, the DS isn't getting the voltage that it wants. 4 AA NIMH batteries easily will go over 5v if you charge them. I don't know how picky the DS is with the voltage it accepts, but it may not like it.

[InfraBlue]

I have made this and it works. The NiHM batterys have around 1.2v so it is producing about 5v. Intstead os a DS jack i put an USB socket there so i charge different stuff e.g mobile phone, xbox 360 controllers.

[Macworldwizardz]

Is it possible to overcharge the DS battery while charging an USB product (ie. iPod)? I am really curious, Because I know how light is converted to electricity. Also, how many solar cells do you think the solar panal carries?

[dark sponge]

USB devices (like iPods) almost always have built in overcharge protection circuits. And which solar panel do you mean?

[dark sponge]

 I'm glad it works for you, have fun with solar power!