I've been using 4 NiMh AA cells in series to power my project but would like the ability to charge while in use via micro USB just like a mobile phone. I'd like to use a lithium ion pack that contains 3 cells in parallel providing 3.7 v and with a capacity of 6Ah in conjunction with a micro USB charging module. However, I'm unclear as to how I can charge these cells as the micro USB charging modules I've seen warn that they are without balancing features making it unsafe to charge Li/Ions in parallel.
A little about the project:
I need the high current capabilities of multiple cells mostly because there is a thermal printer involved that draws a lot of current. Since most of the devices in the system are 5v, my plan is to regulate the 3.7 v (to prevent from dropping below converter's min voltage) then boost it to 5v with a converter/power supply module. The battery pack has built in protection circuitry.
Power Supply / Boost Converter: PSM-120 DC-DC Step-up power supply module with voltmeter - 3-35V to 3.5-35V
Has anyone had experience with these micro USB chargers? Your help is appreciated!