I've made a 16 cell battery with Li-ion 18650's salvaged from laptops in a 4s4p configuration at around 16.4V. I'm using it in a Bluetooth speaker I made with a TDA7492 Bluetooth audio board, and am using this 18650 protection circuit.
I was wondering if I needed a 16V power supply and connect the charge port straight to the protection board, or if I need something like a TP4056 micro usb, but made for 16V.
I'm still new to all this and am taking every chance I can get to learn more about DC voltage. So any help would be appreciated, thank you.
Best Answer
A 16V power supply will be insufficient for your build. You need at least 17V supplied under load.
You could use a notebook charger rated at 19.5V. The protection circuit will handle the limitations, but you have to make sure that the charger can supply sufficient current for the whole pack. At 4 parallel cells, you'd need at least 4A supplied current (and use a charging at 1C).
Other than that, para-series charge is not generally recommended because a single bad cell over time will discharge the pair, which will not fully charge, which will end up with a bad pack consisting of 1 bad pair, 2 relatively good ones and 1 very good one.