I remade it with a schematic (Patreon)

Published:

2022-12-19 03:53:13

Imported:

2023-02

Content

Here's the video as it should have been. I did the full reverse engineering and schematic this time, and the bulk of the circuitry is just to turn the LED on to display charging and discharging.

The first part of the video is the same, as the case was destroyed while opening it. But at about 5 minutes in it goes onto the new video section.

While neatening up the complex schematic I missed an important 10K resistor. See if you can work out where it goes on the first page of the schematic. The answer is at the bottom of the YouTube video description.

https://www.youtube.com/watch?v=UN0IXJbpsXQ

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I missed a resistor on the first page of the schematic while drawing a neater one. Can you work out where it goes? The answer is at the bottom of this description. This is a small keychain solar power bank I bought from eBay. What I didn't know is that it was NOS (New Old Stock) dating back about ten years, and it shows what an amazing leap the circuitry in power banks has made. Instead of a single chip, inductor and smattering of capacitors, this unit has lots of discrete circuitry to give a similar result, but still cheats on the end of charge detection. The unpopulated chip position does correlate to being an LTH7 charge control chip, but has no facility to turn off the LED on charge completion. The existing DW01 LED control hack would not work, since the LTH7 would terminate the charge just before the DW01 turned off the MOSFET (and disabled the LED). It's actually quite an interesting design. Mid-play video-adverts are annoying in technical videos, so I don't enable them. If you appreciate that and enjoy my content then you can help support the channel with a contribution of a dollar or two a month on Patreon. That also lets you critique the (advert free) videos before they are released, gives a more direct means of communication with me and also gives access to the regular relaxed Patreon live streams. https://www.patreon.com/bigclive #ElectronicsCreators Did you manage to work it out? There should have been a 10K resistor between the base of the LED transistor at the left hand side of the schematic, and the collector of the one that switches its base to the 0V rail. The link shown would have shunted the current intended for the LED to the zero volt rail.