I currently have a setup of 4 18650 batteries linked up in series and I have pimoroni amigo pro and a dc to dc buck converter.
I currently have the 4 18650 batteries connected to the dc to dc buck converter which converts the 12v to 4v which then goes to the battery port of the charging board.
The problem is when I plug it into a usb c charging port that I tested to work.
The board doesn’t charge the batteries.
It flashes really quick on the charging light and then it turns off.
There is power through the device port but not into the charging port.
You can’t run a buck converter in reverse to charge the batteries. For charging you would have to replace the buck converter with a boost converter to convert 4V to 12V. But in any case you can’t safely charge 4x18650 batteries in series without using a charger that is designed for exactly that arrangement of cells, which the Pimorini is not.
I’ve removed your email address from your post - this forum is public so a bot will likely scrape it eventually and send you a bunch of spam. You’ll get emails when people reply to this thread, or private message you.
Jeff is on the money here. You need a balance charger to make sure that the cells don’t drift too far apart in state of charge.
Here’s an example of one (though it is very manual so maybe not what you are after)
