Inside a lithium battery monitor (with schematic)

I've seen these on eBay in various forms and decided to get one to reverse engineer.
Rather pleasingly, they have used standard components to make the device, so it does offer a level of hackability for custom voltage threshold measurements.

In hindsight I wish I'd got a version for higher voltage use, as the single cell version dims the display noticeable over the discharge levels. That could be a good thing for a continuously active display though.

The voltage thresholds I measured tallied well with the spec of the module, so it's a useful indicator of cell charge status.

I've not worked out what the mysterious indicator LED position is for. A quick search didn't reveal a version that used it. I've just ordered a different version that uses what appears to be a microcontroller to do the job, with a selectable voltage scaler for multiple lithium battery size options.


I despise intrusive mid-video video-adverts, so despite being able to earn more advertising revenue by using them, I choose not to. 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