Hi.
Those cheap garden lights with a single white LED and a single NiCd cell use a dedicated IC to operate.
The solar panel charges the cell by itself at daylight, but the cell voltage is to be raised to turn the LED on at darkness.
Would it be hackable ? Using/rewiring the circuitry of that same chip to raise the panel voltage to 4V for recharging the LiIon cell at daylight and operate the LED at night ?

----> https://dzrmo.files.wordpress.com/2012/05/dxd003371.png

In other words, how could those cheap garden lamps be fitted with a LiIon cell instead ?

Here is some data for a similar chip :
---->http://www.jhs-ic.com.cn/editor/UploadFile/2009114154241662.doc

 

It would only be possible if you knew the details of the chip, or blob, as the case may be. If it is not an identifiable standard chip your chances of doing anything with it are pretty small.

 

Hi.
Those cheap garden lights with a single white LED and a single NiCd cell use a dedicated IC to operate.
The solar panel charges the cell by itself at daylight, but the cell voltage is to be raised to turn the LED on at darkness.
Would it be hackable ? Using/rewiring the circuitry of that same chip to raise the panel voltage to 4V for recharging the LiIon cell at daylight and operate the LED at night ?

----> https://dzrmo.files.wordpress.com/2012/05/dxd003371.png

In other words, how could those cheap garden lamps be fitted with a LiIon cell instead ?

Here is some data for a similar chip :
---->http://www.jhs-ic.com.cn/editor/UploadFile/2009114154241662.doc

Hi,

Measure the solar panel output and build your own boost circuit to charge the battery, along with a regulator of course that can handle the correct charging method for the cell.

 

Hi.
Those cheap garden lights with a single white LED and a single NiCd cell use a dedicated IC to operate.
The solar panel charges the cell by itself at daylight, but the cell voltage is to be raised to turn the LED on at darkness.
Would it be hackable ? Using/rewiring the circuitry of that same chip to raise the panel voltage to 4V for recharging the LiIon cell at daylight and operate the LED at night ?

You can get colour changing solar garden lights - the datasheet I found for that type of LED says it takes 4V.

The simple flyback converter probably goes a fair bit higher off load - it might charge a lithium cell eventually, but you still have to avoid exceeding the specified terminal voltage in the long term. You won't get much current at the voltage, designing a charge controller that doesn't soak it all up could be a challenge.