Bought one of these https://www.aliexpress.us/item/3256804925720341.html (with the 22.5W USB-C board) and filled it wit h these Panasonic/Sanyo NCR18650GA Flat Top 10A 3500mAh 18650 Battery - Genuin – Liion Wholesale Batteries
It seems to me that 10A should be more than enough given that 22.5W should only be able to draw about 2A or so per battery.
But I’m not getting very much out of the charger, about 33Wh which is only about 2250MAh per batter instead of the 3300 MAh minimum. (If I’ve done my math right). I do see very nearly the same amount of power going in as I get out so I think the charger board is fairly efficient.
I’ve checked the cells after draining the pack to “0%” and they’re still at 3.46V without any power draw. My understanding is that they should be at 2.7V or so before they’re considered empty. Looking at the discharge curve graphs the difference between 3.4V and 2.7V does look like nearly a third of the capacity so that fits with the measurements I got.
Is this just bad programming on the charger and I should find a different charger with better firmware (I doubt I can find any instructions on reprogramming this one). Are there battery packs that people here have had more success with? Or some other solution to this issue?
