Perplexing circuitry (Patreon)

Perplexing solar light

I made this video in two parts while travelling, but now wish I had the other parts or some suitable test equipment to test my theory that it might have a design defect that could overcharge the lithium cell if the light is left in sunshine while switched off. Fortunately in most situations the light will be left switched on continuously after purchase, and will therefore have the charge control circuitry active. The use of a processor controlled transistor for charge control is very similar to the circuitry of the skeleton shaver I reverse engineered a while ago. It makes me wonder if the chip is a microcontroller with a built in dedicated lithium charge system or if it is just relying on software and an analogue to Digital converter to measure the cell voltage. My pondering about whether the chip could somehow use a single pin to measure cell voltage as well as control the transistor is possibly viable if the cell voltage and transistor base voltage were added. Technically speaking the chip could contain a simple zener or fixed voltage reference so the transistor turned off as the cell voltage reached a charged state. Theoretically the base bias resistor is also going to have a hard time on a sunny day when the base is shunted, as the power dissipation would be just above its rating and the processor would also be shunting about 50mA on its control pin. They may be over-economising on these designs. If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- https://www.bigclive.com/coffee.htm This also keeps the channel independent of YouTube's algorithm quirks, allowing it to be a bit more dangerous and naughty. #ElectronicsCreators