Replacement OptoIsolated USB-Uart for Daly Smart BMS

  • Posted 21 April 2021

I found myself with a dead USB-Uart adapter (CH340G based) and subsequently a couple more generic cp2102 adapters for connecting to the Daly Smart BMS.

It seems when the BMS went to sleep and woke up a high voltage may have appeared on the rx/tx lines and fried the chip (did not check/test theory).

Solution: Try an opto-isolated usb-uart

This one is what I got https://www.aliexpress.com/item/4001358913591.html
I changed the original 4-ping connector to a different type for which I had the male/female pair on hand.

After figuring out the pinout from the BMS - I needed 3.3v from the BMS side for the usb-uart dongle - the rest was to add the extra wire to the original cable and try out the dongle.

 

It worked great! No more dead uart-usb dongle, and due to the opto isolation I feel more comfortable connecting the battery pack to my computer.